Physics p2 Essay

Physics 4321 [Paper 2 Section B] (ii)

PAPER 2 SECTION B & C CHAPTER 2 1.

Diagram 9.1 shows the effect of a man falls from a high position to the ground without opening the parachute. Diagram 9.2 shows a man with the same mass falls from the same height when the parachute is open.

Diagram 9.1

What is the meaning of free fall? [ 1 mark]

(ii)

Based on diagram 9.1 and Diagram 9.2, compare the acceleration, the rate of change of momentum and the time of impact. Relate the rate of change of momentum with the time of impact to make deduction on the relationship between the acceleration and the rate of change of momentum. [ 5 marks]

A hovercraft moves on a cushion of air which is trapped underneath it, as shown in Diagram 9.3. The trapped air reduces the friction. The hovercraft starts from rest and as it starts, the propeller produces a forward force until it reaches a constant velocity .

Diagram 9.4 shows a canoe

Diagram 9.4 You are required to give some suggestions to design a canoe which can travel faster and safer . Using the knowledge on motion, forces and the properties of materials, explain the suggestions based on the following aspects: (i) the surface of the canoe (ii) the shape of the canoe (iii) the material of the canoe (iv) the material of the canoe (v) the material of the canoe [ 10 marks ]

Diagram 9.1

(a) (i)

(b)

(c)

Explain why the hovercraft moves with constant velocity in terms of the force acting on it [4 marks]

2.

Diagram 9.1 shows a car and a lorry stopping at a red traffic light. When the traffic light turns green as in diagram 9.2, the car is found to move ahead of the lorry.

Diagram 9.1

Diagram 9.2

(a) What is meant by mass? [ 1 mark ]

(i)

Diagram 9.3 Sketch a velocity-time graph to show the motion of hovercraft.

http://www.ssijbfizikspm.blogspot.com

(b) Based on diagram 9.1 and 9.2, compare the masses of the vehicles and their ability to speed ahead. Relate the mass of the vehicle and the way it can start moving from rest to deduce a concept in physics with regard to the motion of objects. State the physics concept. [ 5 marks ]

Prepared by: En Adnan Shamsudin

Physics 4321 [Paper 2 Section B] (c) Based on the physics concept stated in (b), (i) explain why a driver lurch forwards when a car he is driving comes to a sudden stop, (ii) describe and explain a method which can overcome the situation in (c)(i). [ 4 marks ] Diagram 11.2 (d) Diagram 9.3 shows a water rocket made from an empty 1.5 litre plastic soft drink bottle by adding water and pressurizing it with air for launching.

(a) Name the physics principle involved which makes the ball on the other far end is knocked away from the others. [1 mark] (b)

Diagram 9.3 The objective is to keep the rocket in the air as long as possible. Using the appropriate physics concepts, suggest and explain suitable designs based on the characteristics of (i) the acceleration, (ii) the shape (iii) the structure (iv) the buoyant force (upthrust), (v) the stability of the motion, to improve the water rocket. [ 10 marks ] 3.

Diagram 11.3

Explain, in term of momentum and energy transfer, why the ball on the opposite end is knocked away from the others. [4 marks]

(c) Diagram 11.4 shows five designs of ‘Newton’s Cradle’, P, Q, R, S and T, with different specifications. You are required to determine the most suitable design to make the ball at the end swings up to higher level and at bigger speed. Study all the five designs from the following aspects: (i) The arrangement of the balls (ii) The type of material used to make the balls (iiii) The number of string used to hang the balls (iv) The position of the ball to start the oscillation

Diagram 11.1 shows ‘Newton’s cradle’ which consists of five identical balls suspended in a row from a wooden frame by wires.

Diagram 11.1 When the ball on left end is pulled aside (Diagram 11.2) and allowed to fall, the ball on the far end is knocked away from the others with the same speed as the first ball (Diagram 11.3).



Physics 4321 [Paper 2 Section B] 4.

Diagram 9.1 shows the initial and final position of a student sliding down a slide. Diagram 9.2 shows the initial and final position of the same student sliding down the slide from a different initial position.

(a)

Diagram 11.4 Explain the suitability of the aspects. Justify your choice.. [ 10 marks] (d) In a game, a 50 g white ball of speed 0.8 m s1 hits a 30 g red ball at rest . If the white ball stops after the collision, calculate; (i) the velocity of the red ball after the elastic collision. (ii) the change of the momentum of the white ball. (iii) the impulsive force acting on the white ball during the collision if it is stopped in 0.05 seconds. [5 marks]


(i) What is the meaning of gravitational potential energy of the student? [1 mark] (ii) Observe Diagram 9.1 and Diagram 9.2. Compare the initial position of the student and the speed of the student on reaching the final position. Relate the speed of the student on reaching the final position with the energy gained by the student to make a deduction on the relationship between the initial position and the energy gained. [4 marks] (iii) Name the physics principle that explains the situation in (a)(ii). [1 mark]


Physics 4321 [Paper 2 Section B] (b) Diagram 9.3 shows a baby sleeping in a cradle. The cradle is made to oscillate between position P and Q through the equilibrium position O.

Diagram 11.1 (a) When the paper clip is removed, the balloon propels forward. (i) Name the principle used in the propulsion of the balloon. [ 1 mark ] (ii)

Diagram 9.3 State the changes in energy that occur when the cradle swings from P to O, and then from O to Q. (ii) After some time, the cradle stops oscillating. Explain why. [4 marks] (c) Diagram 9.4 shows an archer getting ready to shoot an arrow towards a target board from a far distance. When he releases the arrow, he observes that the arrow falls short of the target. (i)

Diagram 9.4 Suggest and explain how he would be able to shoot the arrow to hit the centre of the target board, based on the following aspects: (i) The strength of the cord (ii) The force constant of the bow (iii) The material used for the bow (iv) The design of the arrow (iv) The way the arrow is aimed at the target [10 marks] 5.

Diagram 11.1 shows a balloon taped to straw.


Explain what makes the balloon propel forward. [ 4 marks ]

(b) The balloon moves with an initial velocity of -1 4 ms . Then it decelerates for 2 seconds and finally stops. (i) Sketch a velocity-time graph for the motion of the balloon. (ii) Calculate the deceleration of the balloon. (iii) Calculate the distance travelled. [ 5 marks ] Diagram 11.2 shows four racing cars , P , Q , R and S, with different specifications. You are required to determine the most suitable car to complete in the Formula 1 Summer Race.

Diagram 11.2 Study the specifications of all racing cars from the following aspects: (i) The shape of the car (ii) The ridges on the tyres (iii) The engine power (iv) The material for the body of the car. (v) Explain the suitability of aspects. Justify your choices. [ 10 marks ] Prepared by: En Adnan Shamsudin


(a)

7.

Diagram 9.1 (i)

done to enable the machine to lift a car easily in a workshop. You can emphasise on the following aspects in your modification; (i) method so that only small force is applied at piston A (ii) component to control flow of liquid in the hydraulic jack (iii) component in the hydraulic jack to lowered the car (iv) size of pistons (v) type of liquid used [ 10 marks ]

Diagram 9.1 shows two identical feeding bottles floating in liquid P and liquid Q respectively. The feeding bottle floats because the net force acting on the bottle is zero.

Diagram 9.1 shows a hydraulic lift used to raise loads Q and R.

What is the meaning of net force? [ 1 mark]

(ii)

(b)

Using Diagram 9.1 compare the position of the bottles in liquid P and liquid Q. Compare also the weights and the buoyant forces that are acting on the bottles in liquid P and liquid Q. Compare the density of liquid P and liquid Q. Relate the position of the bottle and the density of liquid to deduce a relevant physics concept. [5 marks]

(a)

(ii)

Diagram 9.2

(c)

What is meant by pressure? [1 mark]

Diagram 9.2 shows a simple hydraulic jack.

Explain how load M can be lifted and give a reason why the cross sectional area of piston A is smaller than the cross sectional area of piston B. [4 marks]

(i)

(b)

A force of 100 N is used to push down piston P and able to raise piston Q and piston R. With reference to Diagram 9.1 compare the pressure acted on piston Q and R, the cross sectional area and the force produced at the piston Q and piston R. Relate the cross sectional area of the pistons with the force produced on the pistons. Name a physics principle relating the cross sectional area and the force exerted on pistons Q and R. [5 marks]

Diagram 9.2 shows a cross section of an aeroplane wing. The wing help the aeroplane to be lift up when the plane speeding along the runaway.

The simple hydraulic jack in Diagram 9.2 is not suitable to use to lift a car in a workshop. Using suitable physics concepts, explain the required modification that need to be



Physics 4321 [Paper 2 Section B]

Name the shape in Diagram 9.2 and explain how the aeroplane can be lifted up to the air. [4 marks] (c)

8.

Submarine is used to move underwater. Using suitable physics concepts, explain how you can design a basic structure of a small submarine so that it can be used for an underwater exploration. The design should include the following aspects: (i) the material and thickness of the wall, (ii) shape of the submarine, (iii) able to submerge, (iv) the equipments to detect underwater obstacles and depth [10 marks]

[ 10 marks ] (d)

Diagram 11.2 shows oil drum floats stationary in water. The density of water is -3

1000 kg m .

Diagram 11.1 shows a submarine floating in sea water due to the effect of buoyant force.

Diagram 11.2 Calculate (i) The volume of the oil drum immersed in water. [ 2 marks ]

(a)

Diagram 11.1 What is the meaning of buoyant force? [ 1 mark ]

(b)

Explain how a submarine is able to submerge into deep sea water. [ 4 marks]

(c)

You are asked to investigate the characteristics of four submarines shown in Table 11.1. Explain the suitability of each characteristic of the submarines and determine the submarine which can travel faster, stay l onger in deeper sea water and able to carry more crew. Give reasons for your choice.


(ii)

The buoyant force acting on the oil drum. [ 2 marks ]

(iii)

The mass of the oil drum. [ 1 mark ]



characteristic and suggest the most suitable wing to be installed with the body of the aeroplane. [ 10 marks ]

Diagram 11.1 shows an aeroplane. Diagram 11.2 shows a cross section of the aeroplane’s wing.

10.

Diagram 11.1 (a)

(b)

Name the shape of the cross sectional of the aeroplane wing. [1 mark] The aeroplane can be lifted up when flying due to a difference in pressure of the air between the upper and bottom sides of the wings. (i) Explain how this difference in pressure is produced. [ 3 marks] (ii)

(c)

Diagram 11.2

Diagram 11.1 shows the air balloon which is used as a weather balloon to carry a radiosonde instrument for collecting data about the atmosphere. The weather balloon rises up in the air due to Archimedes’ principle (a) (i)

State Archimedes’ principle. . [1 mark]

(ii)

Explain why a weather balloon that is rising up in the air will stop at certain altitude. . [4 marks]

(b) Diagram 11.2 shows four hot air balloons P,Q,R and S with different features. You are required to determine the most suitable the most hot air balloon which is able to carry three or four people to a higher altitude in a shorter time.

Name the principle involved in your answer in (b)(i). [ 1 mark ]

Table 11 shows characteristic of four designs of the aeroplane wings.

Table 11 You are requested to choose the most suitable wing to be installed to the body of an aeroplane. By referring to the information given in Table 11, explain the suitability of each http://www.ssijbfizikspm.blogspot.com



Diagram 11.3

11.

(i)

By neglecting the mass of the balloon, calculate the mass of helium gas in the balloon. [2 marks]

(ii)

Calculate the buoyant force which acts on the balloon. (Density of air is 1.3 kg m-3) [3 marks]

Diagram 9.1 and Diagram 9.2 show the heating curves obtained when 50 g and 80 g of the solid substance are heated respectively. The melting o point of the substance is 78 C.

Study the characteristics of all the four hot air balloons from the following aspects: The size of the balloon The number of burners The type of the fabric of the balloon The temperature of the air in the balloon Explain the suitability of the aspects. Justify your choice. [10 marks] (c)

Diagram 11.3 shows a balloon which contains helium. The volume of the balloon is 1.2 m3. Density of helium gas is 3

Diagram 9.1

Diagram 9.2 (a) (i)

What is the meaning of melting point? [1 mark]

0.18 kgm- . (ii) Based on the information and the observation on Diagram 9.1 and Diagram 9.2, compare the mass, the time taken to reach the melting point and the time taken by the substance to change into liquid completely. http://www.ssijbfizikspm.blogspot.com


Physics 4321 [Paper 2 Section B] Relate the mass and the time taken by the substance to change into liquid completely to make a deduction on the relationship between the mass and the latent heat of fusion absorbed by the substance. [5 marks]

12.

Diagram 9.1 shows a boy pouring hot coffee into a cup. The hand of the boy is not scalded by the coffee droplets that are spattered from the kettle. Diagram 9.2 shows hot coffee spilling over and getting onto his hand and his hand gets scalded because of the higher heat capacity in it.

(b) Diagram 9.3 shows the phenomenon of sea breeze.

Diagram 9.1

Diagram 9.2

(a) What is meant by heat capacity? [ 1 mark ] (b) (i)

Observe Diagrams 9.1 and 9.2. Compare the temperature of the coffee, the mass of the coffee droplets spatters on his hand and the coffee from the kettle spills on it, and the injury to the hands. State the relationship between the mass of the coffee and the injury that occurs. [ 4 marks ]

(ii)

State the relationship between the heat capacity and the mass. [ 1 marks ]

Diagram 9.3 Using the concept of specific heat capacity, explain how the phenomenon of sea breeze occurs. [4 marks] (c) Diagram 9.4 shows a design of central heating system used in cold country to heat and keep houses warm.

(c) Diagram 9.3 shows a radiator of a car

Diagram 9.4 Suggest and explain how to build a house central heating system which can function effectively based on the following aspects: (i) The specific heat capacity of the liquid (ii) The boiling point of the liquid (iii) The properties of material used for transmission pipe (iv) The size of the fan used to blow the heat from radiator http://www.ssijbfizikspm.blogspot.com

Diagram 9.3 Water is used as a cooling agent in a radiator. Explain how water is used [ 4 marks ]


Physics 4321 [Paper 2 Section B] (c) Table 11 shows the design of five torchlights P, Q, R, S and T.

(d) You are required to give some suggestions to design an efficient thermometer to be used in physics laboratory. Using your knowledge about heat and properties of materials, explain how to built a thermometer which can function effectively based on the following aspects, (i) Strength of the thermometer (ii) Choice of the thermometric liquid (iii) Sensitivity of the thermometer (iv) Design of the thermometer so that the scale can easily be read. (v) Melting point and freezing point of the liquid [ 10 marks ] CHAPTER 5 13.

Diagram 11.1 shows Ali standing at the side of a pond. Ali can see the image of the fish and the image of the dragon-fly in the water as shown by the ray diagram.

(a) (i)

(ii)

(b) (i)

(ii)

Table 11 You are asked to investigate the characteristics of the five torchlights shown in Table 11. Explain the suitability of each characteristics of the torchlight and determine the torchlight which can produce a strong parallel beam of light. Give reasons for your choice. [10 marks]

Diagram 11.1 What is the meaning of virtual image? [1 mark] Explain how Ali can see the image of the fish and the image of the dragonfly. State the phenomenon of light that is involved in each case. [4 marks]

14.

Diagram 11.1 shows two convex lenses, P and Q, used in an astronomical telescope. The focal length of P is 40 cm and for Q is 10 cm

Calculate the angle and . θ α [ Refractive index of water is 1.33 ] [4 marks] State one characteristic of the image of the dragon-fly. [1 mark] Diagram 11.1



Physics 4321 [Paper 2 Section B] (iii) State the characteristics of image formed in the camera [1 marks]

(a) What is the meaning of focal length of lens ? [ 1mark ] (b) By using suitable apparatus, explain how the focal length of both lenses can be estimated. [ 4 marks ] (c) Diagram 11.2 shows an arrangement of lenses to construct a simple astronomical telescope using lens P and lens Q.

15.

Diagram 11.1 and 11.2 show two photographs captured using two lenses with different focal length.

Diagram 11.1 (a) (i)

What is meant by focal length? [ 1 mark ]

(ii)

Using Diagram 11.1 and Diagram 11.2, compare the thickness and the focal length of the lenses. Explain the relationships between the thickness and the power of the lens. [4 marks]

Diagram 11.2 You are asked to investigate the arrangement and characteristics of the lenses used to construct the simple astronomical telescope as shown in Diagram 11.3.

Diagram 11.3 Explain the suitability of the arrangement and each characteristics of the lenses and determine the arrangement which can produce the brightest and sharp image at normal adjustment.

Diagram 11.2

(b) An object is placed 30 cm in front of a lens with a power of + 5 D. (i) An object is placed 30 cm in front of a lens with a power of + 5 D. [ 2 marks ] (ii)

Calculate the distance of the image. [ 2 marks ]

(iii)

Calculate the magnification of the image [ 1 mark ]

(c) Diagram 11.3 shows an astronomical telescope. An astronomical telescope is used to view very large objects like moon.

(d) A camera has a convex lens of focal length 5 cm is used to capture an object of 1 m in height and 4 m from the camera. (i) determine the image distance from the camera [2 marks] (ii)

Calculate the height of image produced in the camera [2 marks]


Table 11.1 shows the characteristics of four different simple astronomical telescopes. Prepared by: En Adnan Shamsudin

Physics 4321 [Paper 2 Section B] Calculate, (i) the refractive index of the water in the pool. (ii) the apparent depth of the image. [5 marks]

(d) Diagram 11.2 shows a glass window which opens outwards at an angle θ. Explain the suitability of each characteristic of the telescope and determine the most suitable telescope to be used to observe very far object. Give reason for your choice. [ 10 marks ] 16.

Total internal reflection occurs when light travels from a denser medium to less dense medium and the angle of incidence is greater than the critical angle. (a) What is the meaning of critical angle? [1 mark] (b) (i)

Write an equation to show the relationship between the critical angle, c, and the refractive index, n, of a medium.

(ii)

Use the equation in (b)(i) to explain why total internal reflection is easier to occur in diamond than in glass. [ Refractive index of glass = 1.5, refractive index of diamond = 2.4 ] [4 marks]

Diagram 11.2

Diagram 11.3

Diagram 11.3 shows the side view of the window. If rays of sunlight incident on the window undergo total internal reflection at points like X, direct sunlight would not be able to enter the room and it would be cooler. Four designs P, Q, R and S of the window are available and are designed such that it can be opened at a maximum angle of θ. Table 11 shows the characteristics of the glass used and the angle θ of each design.

(c) Diagram 11.1 shows a ray of light from an object at point P at the bottom of a swimming pool travelling from water into the air. Table 11 Explain the suitability of each characteristic of the glass and the size of the angle θ and determine the most suitable design to be used so that the room would be kept cool during the day. Give reasons for your choice. [10 marks]

Diagram 11.1 http://www.ssijbfizikspm.blogspot.com



(d)

Diagram 11.1 shows a stamp collector examines a stamp using a magnifying glass.

18.

You are given a convex lens. Describe how the power of the lens can be determined. State the relationship between power and focal length of a lens. [5 marks]

Diagram 9.1 and Diagram 9.2 show the identical objects located at different positions in front of identical concave mirror. Real images with different sizes are produced.

Diagram11.1 Table 11 shows characteristics of four types of magnifying glass

Diagram 9.1

Diagram 9.2

(a) (i) What is the meaning of real image? (ii) Using Diagram 9.1 and Diagram 9.2, compare the object distance, the size of image formed and the image distance. Relate the position of the object distance and the size of the image formed to make a deduction on the relationship between the object distance and the magnification scale. [ 5 marks ] Table 11 (a) What is meant by the focal length? [1 mark] (b) You are requested to choose the magnifying glass to be used by a stamp collector to examines the stamps. By referring to the characteristics given in Table 11, explain the suitability of each characteristic and suggest the most suitable magnifying glass to be used by a stamp collector. [10 marks] (c) A student is using a magnifying glass M to observe a small ant at a distance of 2 cm. (i) Calculate the image distance. [2 marks] (ii)

(b) Diagram 9.3 shows a photograph of a concave mirror producing upright and magnified image.

Diagram 9.3 Draw a ray diagram to show the formation of the image formed as shown in Diagram 9.3. (c) Diagram 9.4 shows a ray diagram of a slide projector.

Determine the linear magnification of the image of the ant. [2 marks]



Physics 4321 [Paper 2 Section B] (b) Diagram 9.3 shows the structure of a simple camera.

Diagram 9.4 The slide projector is needed in your school hall. You are required to modify the slide projector so that it can produce clearer image and can be seen by 800 students. Suggest and explain based on the following aspect: (i) The power of the bulb used. (ii) The position of the bulb from the concave mirror. (iii) The curvature of the concave mirror. (iv) The position of the slide from the projector lens. (v) Position of the screen from the projector. [ 10 marks ] 19.

Diagram 9.1 and Diagram 9.2 show light rays from two identical objects passing through two identical convex lens. Both lenses produce real images. F is the focal point for the lens.

(i) Explain how the camera is able to capture the image of a distant object. [ 3 marks ] (ii)

(c) A student is given two convex lenses , R and S. The focal length of R and S are 20 cm and 5 cm respectively. Suggest and explain how to build a microscope which produces a sharp image and magnified image based on the following aspects: (i) Arrangement of lenses (ii) Position of object (iii) Position of the first image (iv) Distance between two lenses. [ 8 marks ] (d)

(a) (i)

Name the phenomenon involved. [ 1 mark ]

(ii)

Observe Diagram 9.1 and Diagram 9.2. Compare the object distance, the size of the image and the power of the lens. Relate the size of the image with the object distance. [ 1 mark ]


State the range of the object distance where the image formed is sharp. [ 1 mark ]

Suggest two modifications that need to be done to the microscope to produce a bigger final image. [ 2 marks ]



Diagram 9.1 and Diagram 9.2 show the parallel rays of light directed towards the convex lenses J and K. Both the lenses produce real images. F is the focal point for each lens.

(i)

State the function of the eyepiece. [1 mark]

(ii)

State the characteristics of the image formed by a microscope. [3 marks]

(c) You are given two convex lenses S and Q of different focal length. Lens S has a longer focal length than lens Q. (i) Using the two lenses above explain how are you would make a simple astronomical telescope. [4 marks] (ii)

21.

(a) (i)

Suggest modification that need to be done on the telescope to produce clearer and bigger images. [6 marks]

Diagram 9.1 shows a light ray passing through from air into water. Diagram 9.2 shows a light ray passing through from air into glass. [Refractive index: Glass= 1.50 , Water=1.33]

What is meant by focal length? [1 mark]

(ii)

With reference to Diagram 9.1 and Diagram 9.2, compare the thickness of the lenses and the effects it has on the refracted rays to make a deduction regarding the relationship between the thickness of the lenses and their focal length. [5 marks]

(b) Diagram 9.3 shows the ray diagram of a simple microscope.

Diagram 9.1 Diagram 9.2 (a) (i) Name the phenomenon of light as shown in Diagram 9.1 and Diagram 9.2. [ 1 mark ] (ii)

What is the meaning of refractive index? [ 1 mark ]

(b) Observe Diagram 9.1 and Diagram 9.2. Compare the refractive index, the density and the angle of refraction of light ray. Relate the density of medium with the angle of refraction to make a deduction of the relationship between the density of medium and the refractive index. [ 5 marks ] Diagram 9.3 http://www.ssijbfizikspm.blogspot.com


Physics 4321 [Paper 2 Section B] (iii) Observe Figure 10.1 and 10.2. Compare the wave patterns produced by the spherical dippers. State the relationship between the distance of two coherent sources and the separation / distanceof two consecutive nodes or antinodes lines. [ 10 marks ]

(c) With the aid of ray diagram, explain how a man shoots a fish in water so that he hits the target. [ 3 marks ] (d) (i)

You are given two pieces identical o

0

prism with internal angle 45 , 90 and 0

45 and two converging lenses to make a binocular. Using the material stated above, explain how you are going to build a simple binocular. [ 6 marks ] (ii)

(b) Sonar technique can be used to determine the distance between two positions. Ultrasonic wave is used in this technique. (i) What is sonar? [ 1 mark ]

Suggest modifications need to be done on the simple binocular to produce brighter and bigger image. [ 4 marks ]

(ii) Explain why using ultrasonic wave is better than just ordinary sound waves. [ 2 marks ] (iii) A marine researcher wants to use ultrasonic sound to determine the depth of the ocean bed. Explain how he can do so. [ 7 marks ]

CHAPTER 6 22.

Diagram 10.1 and 10.2 show wave pattern produced by the vibration of two spherical dippers on the water surface set to be at different distances. 23.

Diagram 12.1 shows the pattern of sea waves when approaching the beach.

Diagram 10.1

Diagram 12.1 (i) Name the wave phenomenon shown in Diagram 12.1. [1 mark] Diagram 10.2 (a) (i) What is the wave phenomenon shown in diagram 10.1 and 10.2? [ 1 mark ]

(ii) Explain in terms of the wave phenomena in 12 (a)(i), why the water waves follow the shape of the beach as it approaches the shore. [4 marks]

(ii) Explain why the water level in the ripple tank must be at constant depth during the experiment. [ 4 marks ] http://www.ssijbfizikspm.blogspot.com


Physics 4321 [Paper 2 Section B] -

(b) The beach in Diagram 12.1 will be used as a place where fisherman boats are kept.

the location to keep the boat material used for the retaining wall the height of retaining wall size of slit

Explain the suitability of the location and the characteristics of the retaining wall and determine the most suitable design to keep the boat safely. [10 marks] (c) Diagram 12.3 show a pattern of wave formed when the water waves with a speed of 6 cm s propagates from a deeper area to a shallow region in a ripple tank.

Deep area λ = 0.8 cm

(i) (ii)

24.

You are assigned to investigate the design for the location to keep the boats and the characteristics of the retaining wall as shown in Diagram 12.2 based on the following aspects: http://www.ssijbfizikspm.blogspot.com

-1

Shallow area λ = 0.5 cm Diagram 12.3

Calculate: the frequency of water waves at the deeper region the speed of the water waves at shallow region. [5 marks]

A student carries out an experiment to investigate a water wave phenomenon using a ripple tank. Diagram 10.1 and Diagram 10.2 show the pattern obtained on the screen of the ripple tank when two vibrators, S and T, are vibrating simultaneously.

Diagram 10.1 Prepared by: En Adnan Shamsudin


Diagram 10.2 (a) (i) State the reason why the depth of water in the ripple tank must be uniform. [1 mark] (ii) Name the water wave phenomenon that is being investigated. [1 mark] (iii) State the amplitude of the wave along the nodal lines. [1 mark] (iv) Using a suitable diagram, explain how a nodal line is formed. [2 marks]

Diagram 10.3 Suggest and explain improvements to the sound system and transmission of the sound so that spectators all around the stadium can hear the announcement clearly. Your answer should cover the following aspects: (i) The number of loudspeakers (ii) The position of the loudspeakers (iii) The amplification of the sound [6 marks] (d) The loudspeaker used in (c) is as shown in Diagram 10.4

(b) Observe Diagram 10.1 and Diagram 10.2. (i) Compare the distance between vibrators S and T. [1 mark] (ii) Compare the distance between adjacent nodal lines. [1 mark] (iii) Compare the wavelength of the water waves. [1 mark] (iv) State the relationship between a and x. [a = distance between the vibrators, x = distance between adjacent lines] [2 marks]

Diagram 10.4 Explain whether D and L should be big or small so that sound from the loudspeaker can be transmitted over a longer distance. [4 marks]

(c) Diagram 10.3 shows the plan of a football stadium. When an announcement was made using only one loudspeaker, spectators at positions such as P, Q and R could not hear the announcement clearly.




Diagram 10.1 and Diagram 10.2 show the pattern of interference using coherent sources of water waves.

Diagram10.4 Using the appropriate physics concepts, suggest and explain the modifications that have to be done to reduce the noise pollution. The modifications should include the following aspects: (i) Materials used for floor, ceiling and wall. (ii) Finishing for table and countertops. (iii) Solution for large windows (iv) Dining space design [ 10 marks ]

Diagram 10.1 Diagram 10.2 (a) How does constructive interference occur? [ 1 mark ] (b)

(c)

Using Diagram 10.1 and Diagram 10.2, compare the distance between the two coherent sources, wavelength of the propagating water waves and distance between two consecutive antinodes. [ 4 marks ] Relate the distance between the two coherent sources with the distance between two consecutive antinodes. [ 2 marks]

26.

Diagram 10.1 shows a tuning fork vibrating near a microphone. The sound waves detected by the microphone are displayed on the screen of a Cathode -Ray Oscilloscope (CRO). When the tuning fork is struck harder , sound produced is louder and the sound waves produces are shown in Diagram 10.2.

(d) Diagram 10.3 shows tourists at a beach observing the sunset.

Diagram 10.3 Using physics concepts, explain why the tourist can still able to see the sun even though it has already set. (e)

Diagram 10.4 shows a restaurant in the town of Seremban. The restaurant is always packed with customers and always noisy. A student and his parents often visit the restaurant to enjoy a pleasant dinner. The restaurant in Diagram 10.4 is not suitable for a quiet evening and they decided to suggest a few modifications to the restaurant owner.


Diagram 10.1

Diagram 10.2

(a) What is the meaning of longitudinal wave? [ 1 mark ] (b) Using Diagram 10.1 and Diagram 10.2, (i) Compare the amplitude of vibrations of tuning fork. (ii) Compare the peak values a1 and a2of the waves displayed by the oscilloscope. (iii) Relate the amplitude of vibrations of tuning fork to the peak values. Prepared by: En Adnan Shamsudin

Physics 4321 [Paper 2 Section B] (iv) (v)

Relate the peak values to the loudness of the sound produced. Hence, deduce the relationship between the loudness of the sound and the amplitude of the wave. [ 5 marks ]

(c) Explain how the sound wave is used to determine the depth of an ocean. [ 4 marks ] (d) You have been assigned as a consultant to assemble a speaker system to improve the acoustics of a school hall. Using the appropriate concept explain how the installation of the speaker system and the other modifications that can improve audible sound. In your explanation , elaborate on the following aspects: (i) Distance between two stereo speakers. (ii) Wall and floor finishing (iii) Power of the loud speakers (iv) Positioning of speakers and microphones. [ 10 marks ]

(a) What is the meaning of the labeled “6V, 24 W” on the filament lamp? [1 mark] (b) (i) Observe Diagram 10.1and Diagram 10.2. Compare the reading of the ammeter and the brightness of the filament lamp M and N. [2 marks] (ii) Observe Diagram 10.3 and Diagram 10.4. Compare the thickness of coiled wire of the filament lamps. [1 mark] (iii) Relate the brightness of the filament lamp with the thickness of coiled wire to make a deduction on the relationship between thickness of coil wire and the heat produced by the filament lamp [2 marks] (c) Diagram 10.5 shows two types of plug for the electric kettle that can be connected to the electric supply. Diagram 10.5(a) uses two pin plug, while Diagram 10.5(b) uses a three pin plug with an earth wire.

CHAPTER 7 27.

Diagram 10.1 and Diagram 10.2 show two circuits. Each circuit contains an ammeter, 4 cells, rheostat and a filament lamp labeled 6V, 24 W. Diagram 10.3 and Diagram 10.4 show the thickness of coiled wire of the filament lamp M and N, respectively.

Diagram 10.5(a)

Diagram 10.5(b)

Explain why a three pin plug is more suitable compared with a two pins plug. [4 marks]

Diagram 10.1

Diagram 10.2

(d) Diagram 10.6 shows a water heater used to boil water.

Diagram 10.6 Filament lamp M Diagram 10.3


Filament lamp N Diagram 10.4

Using appropriate physics concepts, suggest and explain how to build a water heater which can boil a larger quantity of water faster , Prepared by: En Adnan Shamsudin

Physics 4321 [Paper 2 Section B] more efficient, and more safety based on the following aspects; (i) type of material used for the heating element of the water heater (ii) shape of the heating element of the water heater (iii) melting point of the heating element of the water heater (iv) rate of rusting of the heating element of the water heater (v) additional component used for safety when the water boil [10 marks] 28.

Table 12 Explain the suitability of each characteristic of the four metals and determine the most suitable metal to be used as the fuse wire. Give reasons for your choice. [10 marks]

Diagram 12.1 shows a hair dryer labelled 240 V, 500 W connected to a three pin plug. Diagram 12.2 shows the fuse in the three pin plug.

(c)

The hair dryer is Diagram 12.1 is switched on. (i) Calculate the current flowing through the hair dryer. (ii) State whether the 0.5 A fuse is suitable to be used in the plug. (iii) Calculate the energy used by the hair dryer when it is switched on for 10 minutes. [5 marks]

28.

Diagram 12.1 shows a typical circuit on a household electrical appliance that using a fuse.

Diagram 12.1

Diagram 12.2 (a)

(b)

State two properties of the material of the heating element in the hair dryer. [4 marks] (i) What is the meaning of the label 0.5 A on the fuse? [1 mark] (ii) Table 12 shows the specification of a few metals to be used as a fuse wire.


Diagram 12.1 (a) What is a fuse? [ 1 mark ] (b) Explain the advantages o parallel circuit in a house wiring system. [ 4 marks ] (c) An immersion heater its specifications of 240V , 500 W is used to boil water. The efficiency of that immersion heater is 85. (i) What is meant by 250 V, 500 W? [ 1 mark ]



(iii)

Calculate the electric current that passes through the immersion heater. [ 2 marks ] Calculate the output power of the immersion heater. [ 2 marks ]

(d) Fuse takes some time to melt or blow. A fastblowing fuse is required to protect semiconductor equipments which cannot stand high current surge for too long. When a fuse blows, sparking may occur and produces high temperature. The fuse wire is placed in a sheath or catridge as shown in Diagram 12.2 to prevent its sparks from causing damage.

CHAPTER 8 29.

Diagram 10.1 and Diagram 10.2 show two identical electromagnets, X and Y. The current flow in electromagnet X is 2 A and the current flow in electromagnet Y is 3 A.

Diagram 10.1

Diagram 10.2

(a) What is the meaning of electromagnet ? [1 mark]

Diagram 12.1 Table 12.1 shows the specifications of five fuses tat can be used to protect a semiconductor device.

(b) Using Diagram 10.1 and Diagram 10.2, compare the amount of iron filings attracted, current flow and the magnetic field strength of the two electromagnets. Relate the current flow with the magnetic field strength to make a deduction on the relationship between magnetic field strength and the amount of iron filings attracted in this situation. [5 marks] (c) Diagram 10.3 shows an electromagnet crane.

Table 12.1 Determine the most suitable fuse to protect a 240V, 2000 W semiconductor material device. Study the specifications of all five fuses based on the following aspects: The thickness of wire The rating of fuse The catridge type The melting point Explain the suitability of the aspects and justify your choice. [ 10 marks ]


Explain how the electromagnet crane can be used to lift scrap metal. [4 marks] (d) A man needs an adaptor to charge his handphone as shown in Diagram 10.4. The transformer inside the adaptor is used to reduce the 240 V alternating current (a.c) to 12 V direct current (d.c). Prepared by: En Adnan Shamsudin


Using the knowledge of a transformer and rectifier, suggest and explain how to built an adaptor which can be used to charge the handphone. (i) The type of transformer (ii) The ratio of number of turns in primary coil to the number of turns in secondary coil (iii) The type of core (iv) The electronic component that should be connected to the output of the secondary coil (v) The material of wire used [ 10 marks ]

[10 marks] (d) Diagram 12.3 shows a 12V, 48W bulb lights up with normal brightness when it is connected to a 240V main supply through a transformer.

30. Diagram 12.1 shows a simple transformer.

Diagram 12.1 (a) State the transformations of energy involved in Diagram 12.1. [ 1mark] (b) Explain how the transformer works [ 4 marks] (c) You are asked to investigate the design and the characteristic of four transformers shown in Diagram 12.2.Explain the suitability of each characteristics of the transformer and determine the transformer which can be use as an ideal transformer. Give reasons for your choice.


Calculate: (i) the output voltage of the transformer (ii) the number of turns of the primary coil (iii) the efficiency of the transformer .



a

When a current flows through the solenoid it produces a magnetic field and then becomes electromagnet. (a) What is a meaning of electromagnet ? [ 1 mark ] (b) Diagram 12.1 shows a graph of number of paper clips attached, n against current, I, for solenoid.

Diagram 12.1 (i)

Based on the graph, state the relationships between n and I . What can you conclude about the strength of electromagnet? [ 2marks]

(ii)

State two physical quantities that affect the strength of electromagnet? [ 2marks]

(c) You are asked to investigate the design and the characteristics of four alternating current generators shown in Table 12.1. Explain the suitability of each characteristic of the alternating current generators and determine the alternating current generator which can supply a large direct current to an electrical component S shown in Diagram 12.2.

(d) Diagram 12.3 shows a model for transmission of electrical power. The resistance of the transmission cable in the model is 30Ω.

(i)

Diagram 12.3 Name a type of conductor that is most suitable to be used as transmission cable. [ 1 mark ]

(ii)

Calculate the current that flows through the transmission cable [ 2 marks ]

(iii)

The power loss due to heating effect of the transmission cable [ 2 marks ]

Diagram 12.2 http://www.ssijbfizikspm.blogspot.com



Diagram 12.1 shows a bulb labelled 12 V, 24 W is connected to the output of a transformer. The efficiency of the transformer is 40%.

33.

Diagram 10.1 and Diagram 10.2 show how induced current are produced in solenoids

(a) (i) Name the type of transformer. [1 mark] (ii) Explain the working principle of the transformer. [4 marks] (b) Calculate (i) the current flow in the secondary coil. (ii) power input in the primary coil. [5 marks] (c) You are asked to investigate the design and the characteristics of four transformers shown in Diagram 12.2.

Explain the suitability of each characteristic of the transformers and determine which transformer has the highest efficiency. Give reasons for your choice [10 marks]

(a) What is meant by induced current? (b) Using Diagram 10.1 and 10.2, compare (i) The number of turns of the solenoid. (ii) The deflection of the galvanometer pointer. (iii) The rate of cutting of the magnetic flux. (iv) The magnitude of induced current produced. [ 4 marks ] (c) Using Diagram 10.1 and 10.2 (i) Relate the number of turns of the solenoid and the rate of cutting of the magnetic flux. (ii) Relate the rate of cutting of magnetic flux and the magnitude of the induced current produced and hence. [ 2 marks ] (d)

Name the physics law involved. [ 1 mark]



Physics 4321 [Paper 2 Section B] (e)

Diagram 10.3 shows a simple step-up transformer

(a)

(b)

(i)

Explain why step-up transformers are used in the transmission of electricity? [ 2 marks ]

(ii)

You are required to modify the transformer in Diagram 10.3 so that it can use as an efficient laptop adapter with output of 18.5 V of direct current. Your suggestions and explanation should be based on the following aspects: - Type of the core used. - materials and diameter of the wire used. - Ratio of the number of turns in the primary coil to the secondary coil. - The arrangement of the primary coil and the secondary coil. - The numbers of diodes used. [ 10 marks ]

(c)

Diagram 10.1 shows one insulated conductor which is moved downwards in a magnetic field. Diagram 1.2 shows three insulated conductors which are moved downwards in the magnetic field.

[ 1 mark ] Using Diagram 10.1 and Diagram 10.2 , compare (i) The number of conductor wires. [ 1 mark ] (ii) The deflection of the galvanometer pointer. [ 1 mark ] (iii) Relate the number of conductor and the rate of cutting of magnetic flux. [ 1 mark ] (iv) Relate the rate of cutting of magnetic flux and the induced current [ 1 mark ] (v) Name the physics law involved. [ 1 mark ] Diagram 10.3 shows the structure of a generator. Explain how the generator can e used to produce electricity.

[ 4 marks ] (d)

34.

What is meant by electromagnetic induction?

Diagram 10.4 shows the cross section of a moving coil microphone which converts one form energy into another.

When sound vibrates the diaphragm , the attached voice coil moves and cut the http://www.ssijbfizikspm.blogspot.com


Physics 4321 [Paper 2 Section B] magnetic field and generates a small electric current in coil. Using the appropriate concepts in physics , suggest and explain suitable modification or ways to enable the microphone to detect sound effectively and generate bigger current based on the following aspects: (i) The thickness of diaphragm (ii) The strength of the material for the diaphragm (iii) The number of turns of coil (iv) The diameter of the coil wire (v) The strength of magnet [ 10 marks ] 35.

(a)

Diagram 10.1 and Diagram 10.2 shows two identical electromagnet, X and Y .

Diagram 10.3 Explain how the circuit breaker works. [ 4 marks] Diagram 10.1 Diagram 10.2 (i) What is meant by electromagnet?

(c)

Diagram 10.4 shows an a.c generator

[ 1 mark ] (ii)

Using Diagram 10.1 and Diagram 10.2 compare the current flow, the amount of iron filing and the magnetic field strength of the two electrodes. Relate the current flow and amount of iron filing attracted by the electromagnet and the magnetic field strength.. [ 5 marks ]

(b) Diagram 10.3 shows a circuit breaker. Diagram10.4


(i)

Explain how the generator works to produce alternating current.. [ 4 marks ]

(ii)

Explain the modification that needs to be done on the generator and the external circuit to enable the generator to be a d.c generator and produce more current. [6 marks]


Physics 4321 [Paper 2 Section B] CHAPTER 9 36.

As a research engineer in a factory, you are asked to investigate the characteristics of several substances in order to produce semiconductors with better conductivity. (a) What is meant by semiconductor? [1 mark] (b)

Name two types of semiconductors. Explain the differences between this two types of semiconductors [5 marks]

(c)

Table 12 shows the characteristics of five substances P, Q, R, S and T.

37.

A semiconductor diode is an electronic device made by joining pieces of p-type and n-type semiconductors. n-type and p- type semiconductors are produced through the doping process

Diagram 10.1 (a)

Diagram 10.2

What is the meaning of doping? [1 mark]

(b)

Using Diagram 10.1 and Diagram 10.2 , compare the connection of diode to the dry cell, the lighting of bulbs and the reading of ammeter. Relate the lighting of bulbs with the connection of diode to the dry cell to make a deduction regarding the relation between the current flowing in the circuits and the connection of diode to the dry cell.. [5 marks]

(c)

Box Y contains four identical electronics component for full wave rectification.

Table 12 Explain the suitability of the characteristics of the substances to be used in the production of a semiconductor with better conductivity and determine the most suitable substance to be used Give reasons for your choice [10 marks] (d)

An extra high voltage (EHT) supply gives 4 kV across the anode and the cathode of a vacuum tube. (i) Name the process that occurs. [1 mark] (ii)

Calculate the velocity of the electron when it reaches the anode tube. [ mass

Diagram 10.3

-31

of electron , m = 9.1 x 10 kg, charge -19 of electron, e = 1.6 x 10 [3 marks]

On Diagram 10.3 draw the electronic components in the circles provided. (ii)


A capacitor is placed across the output to smooth the current. In Diagram 10.3, draw the wave form produced . Prepared by: En Adnan Shamsudin

Physics 4321 [Paper 2 Section B] Explain how a capacitor is used to smooth the current. [4 marks] (d)

38.

Diagram 10.1 shows a transistor circuit. Diagram 10.2 and Diagram 10.3 show the transistor circuit with different microammeter reading and milliammeter reading.

Diagram 10.4 shows a circuit with a transistor that acts as an automatic switch. LED will light up when it is dark.

Diagram 10.1 Diagram 10.4 A technician wants three fans labelled 240 V, 100 W in a room to be automatically switched on when the room is hot. Suggest modifications that can be made to the circuit in Diagram 10.4 so that the three fans can be automatically switched on when the room is hot based on the following aspect: State and explain the modifications based on the following aspects: The electric component to replace light dependent resistor in the circuit. The position of electric component. he used of relay switch in the circuit.. the arrangement of the three fan. electric component to protect the transistor [10 marks]

Diagram 10.2

Diaragm 10.3 (a)


What is the meaning of transistor circuit? [1 mark]


Physics 4321 [Paper 2 Section B] (b)

(i)

(ii)

(iii)

(iv)

Using Diagram 10.1, compare the microammeter reading and the milliammeter reading. Using Diagram 10.2, compare the microammeter reading and the milliammeter reading. Using Diagram 10.2 and Diagram 10.3, compare the change in microammeter reading and the change in milliammeter reading. Relate the microammeter reading, milliammeter\ reading and deduce a physics concept for base current , Ib

39.

(a)

What is meant by a semiconductor? [ 1 mark]

(b)

Diagram 12.1 shows a full wave rectifier circuit.

and collector current, I in a transistor c

circuit.

Diagram 12.1 [5 marks] (i)

(c)

Diagram 10.5 shows a transistor circuit is used to light up a bulb at night. (ii)

(iii)

Draw the waveform of a full wave rectification. [ 1 mark ] What modification can do on the circuit in Diagram 12.1 to smooth the current? [ 1 mark ] Draw on Diagram 12.1 the modification you suggest in (a)(ii). [ 1 mark ]

(iv) Draw the smoothen current. [ 1 mark ] (d)

Diagram 10.5 Explain why the bulb light up at night. [4 marks] (d)

Suggest the modifications need to be done to the circuit in Diagram 10.5 so that it can function as automatically fire alarm switch that needs high voltage. Explain your suggestions base on the following aspects: (i) The electrical components that are needed to replace any components in the circuit (ii) The position of these components in the circuit (iii) The electrical components that is connected to the output transistor

The door of the lift is fitted with a light transmitter and a detector which is a light dependent resistor (LDR). If the LDR detects light, the relay switch is activated and the lift door will close.You are asked to investigate the circuit of the lift, and design suitable circuit to close the door of the lift, if there is no people in front of the lift as shown in Table 12.

[10 marks]



Physics 4321 [Paper 2 Section B] (iii)

(e)

Calculate the frequency of the current. [ 2 marks ]

Sketch the trace of CRO screen of the same current if the time-base is off

[ 1 mark ]

CHAPTER 10 40.

Radioisotopes can be used as tracers to detect leaks from pipes underground. Diagram 12.1 shows a leak that occurred in an underground water pipe.

Table 12 Explain the suitability of the characteristics in Table 12 and than determine the most suitable circuit for the door of the lift. Give a reason for your choice. [ 10 marks ] (d)

Diagram 12.2 shows trace of CRO screen when a potential different connected on it. The Y- gain setting is 2 V / div and timebase is set to 0.1s / div.

(i)

(ii)

(a)

Diagram 12.1 What is meant by radioisotopes? [ 1 mark ]

(b)

With the aid of diagram, explain how radioisotopes can be used to detect the location of the leakage as shown in Diagram 12.1. [ 3 marks ]

Diagram 12.2 What type of current that is connected to the CRO? [ 1 mark ] What is the peak-voltage of the c urrent? [ 1 mark ]



Physics 4321 [Paper 2 Section B] (c)

four hours and the results are shown in Table 12.2.

Table 12.1 shows the characteristics of five radioisotopes.

Table 12.2 Table 12.1 Explain the suitability of each characteristic of the radioisotope and determine the most suitable radioisotope to be used in detecting the leak from pipes underground. Give reasons for your choice [ 8 marks ] (d)

Diagram 12.2 shows the decay chain of Radon-222.

41.

(i)

Name the source that has the shortest half-life? [ 1 mark ]

(ii)

The experiment continues until the time is 6 hours. Calculate the number of particles emitted per minute from source K. [ 2 marks]

Diagram 12.1 shows a Geiger Muller tube (GM tube) an a rate meter which are used to detect radioactive radiation.

(a)

Diagram 12.1 What is meant by radioactivity? [ 1 mark ]

(e)

(i)

What is the number of neutrons in Rn222? [ 1 mark ]

(ii)

Write an equation to show the decay of Rn-222 to Po-218. [ 2 marks ]

(iii)

Determine the number of alpha particles and beta particles produced in the decay. [ 2 marks ]

(b)

Explain how the GM tube is able to detect the radioactive radiation. [ 4 marks ]

(c)

Radioactive material is also used in smoke detectors. You are assigned to study the characteristics of some radioactive materials and the type of logic gates used in the smoke detector shown in Table 12.1.

A lab assistant measures the number of particles emitted per minute from two different radioactive sources K and L. The measurements are repeated each hour for




(a)

(a)

(b)

Diagram 12.1 shows a system used in a factory to ensure the volume of guava juice in a bottle is uniform.

The radioactive source, radiation detector and counter are used to detect the volume of guava juice. The radioactive source contains a radioisotope. What is meant by a radioisotope? [1 mark] Table 12.2 shows the characteristics of five radioisotopes P, Q, R, S and T.

Table 12.1 [ 10 marks ] (d)

(i)

Copy and complete the equation for the radioactive decay shows below by writing the appropriate numbers in box provided.

As a factory engineer, you are required to determine the most suitable radioisotope that can be used by the system to ensure the volume of guava juice is uniform. Study the characteristics of all 5 radioisotopes and explain the suitability of the aspects. Determine the most suitable radioisotope and give the reason for your choice. [10 marks] (c)

(ii)

Calculate the mass defect in kg. [ 2 marks ]

(iii)

Calculate the energy released. [ 2 marks ]


Table 12.3 shows the reading of the rate meter for 6 bottles through detector and radioactive source .

(i)

State one detector that is suitable to be used purpose. [ 1 mark]



(d)

Based on table 12.3, which bottle shows the least volume of juice and state the reason for your answer. [3 marks] In a radioactive decay series, Uranium-238 decays to become Radium-226 by emitting alfa and beta. Determine the values of X and Y? [5 marks]

-END-



CHAPTER 2 (d)

Question No. 1 (a)(i) The object falling under the force of gravity only (a)(ii) The acceleration Diagram 9.1 larger than Diagram 9.2 The rate change Diagram 9.1 more than Diagram 9.2 The time impact Diagram 9.1 more than Diagram 9.2 When the time impact is smaller, the rate change of momentum When the acceleration is large, the rate change of momentum is large is large

Design or way

Explanation/reason

Acceleration

Smaller mass

Shape

Nose cone // Bullet shape on top of the body The bottle filled with mixture of water and air Equipped with parachute

The smaller the mass the smaller its inertia. Therefore the rocket will accelerate faster. To improve the aerodynamics of the rocket.

Structure

Buoyant force (upthrust)

Stability of the motion

(b) (i) (ii)

The force forward = friction The resultant force is zero The object move with constant velocity

(c)

The parachute increases the surface area of an object so it has more contact with the wind, which decreases the speed of the object (due to air resistant) Helps to stabilize the water rocket by lowering the centre of pressure (gravity)

Question No. 3 modification The surface is smooth Aerodynamic Low density Big peddle strong

reason Reduce water resistance Reduce friction Lighter Increases the force Not easy to broke down

Question No. 2 (a) Mass is the amount of matter in an object. (b) Mass Ability to speed ahead Stopping (from rest)

(c)

Fitted with fins spaced equally around the rocket body.

Serves as the propulsion of the water rocket//The air pressure propels the rocket skyward (upward)

(i) (ii)

Lorry Mass of the lorry is bigger. Takes longer time to speed ahead. Harder//slower to stop moving. Takes longer time to stop moving.

Car Mass of the car is smaller. Easier//faster to speed ahead. Easier//faster to stop moving. Takes shorter time to stop moving.

The inertia of the driver maintains the forward motion when the car stops suddenly. Wearing a seat belt: Restrains the body of the driver from being thrown forward//inside or outside the car. It slows down the forward movement of the driver when the car stops suddenly

(a) The Principle of Conservation of Momentum / Energy (b) When the ball on one end is pulled up and let to fall, it strikes the second ball which is at rest and comes to a dead stop. The momentum of the ball becomes zero as its velocity is zero. The Principle of Conservation of Momentum states that in a collision between two objects the total momentum of the objects in the system remains unchanged. The energy and momentum from the first ball is transferred to the second ball and then transmitted through the balls at rest to the ball on the other end. Because the momentum and energy is maintained in this system, the ball on the opposite side will move at the same velocity as the ball that were in initial motion (c) The balls touch each This will reduce losses of energy which other will reduce the speed of the balls Steel balls are hard and produce highly The type of material elastic collision. Energy can easily used to make the balls is propagates through the intermediate steel balls. Two strings used to This string arrangement restricts the hang each ball balls’ movements to the same plane. High position of the ball, high potential the position of the ball energy and will change to high kinetic to start the oscillation energy. The last end ball will swing at bigger speed. The most suitable design is Q because the ball s touch each other, made from steel, use two strings attached to each ball and the initial position of the ball is high. (d) (i) m1u1+ m2u2= m1v1 + m2v2 (5)(0.8) + (3)(0) = 0 + (3) v2 v2 = 1.33 ms-1 (ii) m1v1 - m2u2 = 0 – (0.05)(0.8) = -0.04 kgms-1 (iii) Impulsive force = -0.04 / 0.05 = 0.8 N

Question No. 4 (a) (i) Energy due to height (ii) Initial position of the student in Diagram 9.1 is higher The speed of the student on reaching the final position in Diagram 9.1 is higher The higher the speed of the student, the higher the energy The higher the position , the higher the energy gained (iii) Principle of Conservation of Energy (b) (i) elastic potential energy to kinetic energy and gravitational potential energy elastic potential energy and kinetic energy to gravitational potential energy (ii) due to damping work done against air resistance // loss of energy due to the extension and compression of the molecules in the system (c) strong // high strength it won’t break easily high force constant store higher elastic potential energy strong // high strength // any suitable material it won’t break easily thin // aerodynamic // streamline less air resistance slightly above the target the path is parabolic / curved/downward // due to free fall motion Question No. 5 (a)

(b)

(i) (ii)

CHAPTER 3 Question No. 6 (a)

(i) Sum of two or more forces to produce one resultant force. (ii) 1. Bottle in liquid Q floats lower 2. Weight and the buoyant force are equal and the same in both cases. 3. Density of liquid P is higher. 4. As the density of liquid decreases, the lower the bottle floats. 5. When density of liquid decreases the volume of liquid displaced increases to produce the same buoyant force.

(b) 1. 2. 3. 4.

When force is applied to piston A Pressure is produced and transmitted uniformly throughout the liquid towards piston B // Pascal’s Principle Pressure multiply by the surface area of piston B will produce the output force that lift load M. Cross-sectional area of piston A is smaller than piston B to produce large output force.

(c) Suggestion Fix a long handle on piston A Equip the hydraulic jack with valves

Priciple of conservation of momentum Air expels at high velocity Produces momentum backwards / to the left Causes thrust of momentum forward/ to the right With same magnitude of force but in opposite direction

(i)

(ii)

a=v–u t =0–4 2 = 2 ms-2 (iii) s = 1 2 2

(4) (2)

= 16 m (c) Characteristics Shape – Inverted aerofoil Ridges on tyres -none Engine power -high Material light and stiff

Reasons High pressure at top // greater downward force//high stability Less friction during motion Greater forward thrust Does not break easily on impact

I choose S Because shape – inverted aerofoil , ridges on tyres –none, engine power –high and material light and stiff

Use released valves Piston A is made smaller // piston B bigger. Oil as liquid

Reasons Small force can produce bigger force /torque to press piston A Liquid can flow in one direction and does not back flow Liquid flows back to the storage reservoir To produce large output force. Does not evaporate easily // does not flow out easily// prevent from rust.

Question No. 7 (a) (i) Force per unit area (ii) Pressure on piston Q = pressure on piston R Cross sectional area of piston Q < Cross sectional area of piston R Force acted on piston Q < force acted on piston R The greater the area, the greater the force Pascal’s principle (b) aerofoil shape The air speed on the upper surface > the air speed on the lower surface. The pressure on the lower surface > pressure on the upper surface. Different in pressure produce lift force. (c) Design Thick wall High density material Strong material Aerodynamic shape Ballast tank Sonar transmitter and receiver

Reasons Water pressure increase with depth Increase mass / can submerge easily Does not break easily Reduce water resistance To increase or reduce weight To estimate distance and depth

Question No. 8 (a) Upwards force cause by weight of fluid displaced by an object when the object is immerse in the fluid. (b) Valve release air from ballast tank. Sea water flooded ballast tank The weight of water displaced is smaller. Buoyant force < Weight of the submarine (c) Choices Reasons The volume of ballast To produce bigger buoyant force tank is higher / easy to rise up / can carry greater weight inside More number of air Can stay longer time under the tanks cylinder carried water / Can rise and submerge many times / more air supply for respiration of crews Can withstand higher Safe when the submarine maximum water submerge very deep in the sea / pressure The body will not break due to high water pressure The suitable shape of Less water resistance in the submarine is motion / can move faster aerodynamic Submarine X Because the volume of ballast tank is higher, more number of air tanks cylinder carried, can withstand higher maximum water pressure and the suitable shape of submarine is aerodynamic. (d) (i) V = 0.2 x 0.8 = 0.16 m3 (ii) B = Vρg = 0.16 x 1000 x 10 = 1600N (iii) mass = 1600 ÷ 10 = 160 kg Question No. 9 (a) Aerofoil (b) (i) The shape of cross section of the wing causes the speed of airflow above the wings to be higher than the speed of airflow below. When the speed of moving air is higher the pressure is lower. Hence air pressure below the wings is higher compare to above the wings. (ii) Bernoulli’s Principle (c)

= 11000 N Direction of force : upwards Question No. 10 (a) (i) Buoyant force equal to weight of fluid displaced (ii) Volume of air displaced equal to volume of a balloon Density of air decreased as a altitude increase Weight of displaced air become smaller At certain height weight of displaced air equal to weight of the balloon (iii) Large balloon To produce bigger buoyant / up thrust // Increase the volume of the air displaced Low density of gas filled in the balloon Lighter Synthetic nylon Light-weight, strong and air-proof material Low mass of radiosonde instrument To produce a bigger upward resultan force R is choosen Large ballon/low density of gas /synthetic nylon / low mass of radiosonde instrument (b)

(i) (ii)

mass = density x volume m=0.216kg V= 1.2m3 m= 1.56kg = 15.6N

Question No. 11 (a) (i) Buoyant force equal to weight of fluid displaced (ii) Volume of air displaced equal to volume of a balloon Density of air decreased as a altitude increase Weight of displaced air become smaller At certain height weight of displaced air equal to weight of the balloon (iii) Characteristics Large ballon

Use 2 burners // Many burners Synthetic nylon High temperature of the air in the balloon Hot air balloon Q is chosen

(d)

The most suitable wing is Y. Because it has a shape of cross section which is upper side is longer than the bottom, large the area of the wing, the low density of the wing materials and the high the difference in speed of air. (i) P=F/A F = 400 x 50 F = 20000 N (ii) Resultant Force = 20 000 – 900(10)

(b)

(i) (ii)

mass = density x volume m=0.216kg V= 1.2m3 m= 1.56kg = 15.6N

Explaination To produce bigger buoyant / upthrust // Increase the volume of the air displaced To produce bigger flame // heat up the gas in the balloon faster Light-weight/ strong /airproof material Reduce the density /weight of the air in the balloon Large balloon, use 2 burners / many burners, use synthetic nylon and has high temperature of the air in the balloon.

CHAPTER 4

CHAPTER 5

Question No. 12 (a) (i) The temperature in which a solid substance change to liquid at atmospheric pressure (ii) The mass of substance in Diagram 9.1 < in Diagram 9.2 Time taken to reach the melting point in Diagram 9.1 < in Diagram 9.2 Time taken by the substance to change into liquid completely in Diagram 9.1 < in Diagram 9.2 The greater the mass the longer the time taken by the substance to change into liquid completely. The greater the mass the greater the latent heat of fusion absorbed (b) In daytime the sun warms the land to higher temperature than the sea. The land has a lower specific heat capacity than sea-water. The air above the land is heated and rises The cooler air above the sea moving to land. (c)

Question No. 14 (a) (i) Cannot be shown on screen (ii) Incident ray from the fish refracted / change direction at B. Refraction Incident ray from the dragon-fly reflected by water surface at A. (b) (i) Reflection θ = 90o – 30o = 60o

Aspect High specific heat capacity of liquid High boiling point of liquid Low rate of rusting material Strong material The size of the fan is big

1.33 =

α = 58.75o (ii)

Question No. 13 (a) The total amount of heat needed to increase the temperature of an object by 1oC (b) (i) 1. the temperature of water droplet = the temperature of water poured on the hand 2. The mass of water droplets is smaller than water poured 3. Hand in diagram 9.1 less injured than that in 9.2 4. the bigger the mass , the more injury to the skin (ii) The bigger the mass of an object, the bigger the heat capacity of the object (c) Water has high specific heat capacity When water in tube pass through the engine it can absorb large amount of heat energy Once water reach the radiator, the heat of the water absorbed by the fin blade of the radiator . The same time the fan in the radiator push the heat out of the car. (d) Thermometer is made from- transparent glass that is strong so that it is not easily broken The thermometric liquid- chosen is mercury uniformly / opaque because it easily expands The capillary tube is made- narrow and thin so that it is more sensitive the shape of the thermometer- is round effect so that it has a magnifying high boiling point and low freezing point so that it can measure very high and low temperature

Virtual / same size / same distance / laterally inverted

(c) Characteristics Concave mirror Bulb at principal focus

Explanation Becomes hot faster Not easily change into vapour Long lasting // not easily rust Not easily breaks To blow large amount of heat

sin α sin 40o

Batteries connected in series Copper connecting wire

Explanation Reflected ray is converging Reflected ray form a parallel beam Produces larger current Low resistance / large current

Torchlight Q is chosen because it has concave mirror, bulb at principal focus, batteries connected in series and copper connecting wire

Question No. 15 (a) Distance between focal pint and the optical centre of a lens (b) 1. The convex lens is aimed/focused to a distant object (infinity) 2. The screen is adjusted until a sharp image is formed on the screen 3. The distance between the screen and the lens is measured 4. Focal length = distance between the screen and the lens (c)

Aspect Longer focal length High magnification Distance = fo + fe Bigger diameter J is chosen

(d)

(i)

1 =1 + 1 f u v 1 = 1 – 1 v 5 400 v = 5.063 cm

(ii)

h2 = v2 h1 v1

Explanation To produce real, inverted and smaller image Produce bigger image Produce image at normal adjustment // image at infinity More light can enter objective lens // more brighter Longer focal length, higher magnification, Distance between two lenses = fo + fe and bigger diameter

h2 = 5.063 100 400 h2 = 1.27 cm (iii) Real , inverted and diminished.

Question No. 16 (a) (i) Distance between optical centre and focal point (ii) Lens in Diagram 11.1 is thinner Focal length in Diagram 11.1 is longer The thinner the lens the longer the focal length The thinner the lens the higher the power of lens

(b)

(i)

1 5

(ii)

20 × 30 30 − 20

600 10

60 1

= 60 cm (iii)

60 30

2

(c) - Convex lens - Image is real and inverted - Convex lens - Image is virtual and magnified - Longer - must have a lower power - have the larger diameter - produce the brighter image S and Convex lens of objective lens, Convex lens of Eyepiece lens, longer fo and larger diameter Question No. 17 (a) angle of incidence when the angle of refraction is 90o (b) (i)

n= (ii)

(c)

1 sin c 41.8o // refractive index for glass is smaller 24.6o // critical angle for diamond is smaller The smaller the critical angle, the easier total internal reflection can occur

(i)

n=

sin 42 o sin 30 o

n = 1.34 (ii)

1.34 = (d)

1 apparent depth

0.75 m high refractive index total internal reflection easier to occur // smaller critical angle thick keep cool / cut off more light low cut off more heat // reduce transmission of heat small critical angle can be easily exceeded // total internal reflection easier to occur Q High refractive index, thick, low thermal conductivity and small angle θ

Question No. 18 (a) The distance from the primary focus to the optical center type of lens is convex, percentage of light is high , focal length is short and size is bigger (b) It should be convex The magnified image can be obtained Percentage of light of the lenses should be high The image would be brighter and clearer Its focal length should be short The power of lens will be high and can be focused at a short distance diameter of lens should be large it is gives a bigger display the most suitable brand is J type of lens is convex, percentage of light is high , focal length is short and size is bigger (c) (i) 1/f = 1/v + 1/u 1/5 = ½ + 1/v v = - 3.33cm (ii) magnification = v/u 3.33/2 1.67 times (d) The lens is directed to a distant object such as tree The screen was adjusted behind the lens until a sharp image Formed the distance between the lens and the screen measured The power of the lens are determined using 1/f The shorter the focal length the more the power of lens.

Question No. 19 (a) (i) Real image is an image which can be formed / projected on a screen. (ii) object distance in 9.1 is shorter than 9.2 Size of image formed in 9.1 is bigger than in 9.2 Image distance in 9.1 is smaller /shorter The shorter the object distance, the bigger the size of the image formed When the object distance is shorter, the magnification scale is bigger. (b)

Question No. 20 (a) (i) Refraction (ii) Object distance in Diagram 9.1 < 9.2 Image distance in Diagram 9.1 > 9.2 Size of image in Diagram 9.1 > 9.2 Power of lens is same The shorter the object distance ,the greater the size of image. (b) (i)

(ii) (c)

(i) Modification f ≤ u ≤ 2f Distance = f0 + fe

Reason Image magnified and real Eyes are not strained// to get normal adjustment microscope 25 cm fo = 10 cm and fe= 20 cm First image is magnified Position of the first Final image is magnified many image < fe times (ii) use less power// longer focal length of eye piece lens Move the object nearer to the focal point (still in between (1F and 2F) Question No. 21 (a) (i) Distance from the optical centre to a focal point. (ii)

(b)

(i) (ii)

(c) (c) Use higher power bulb The filament of the bulb is at the focus point of the concave mirror More curvature lens between f and 2f Increase the distance / further away the screen

(i)

Higher intensity of light / more light produced. The light ray focuses to one point.

Increase the intensity. To produce real and enlarge / bigger images. Larger image produced

Range greater than two focal length ( u ≥2f)

Lens K is thicker than lens J Light ray is refracted more in lens K than lens J. Focal length of lens K is shorter than lens J. Therefore the thicker the lens, the greater the refraction of light and with that the shorter the focal length of a lens will be As a magnifying glass. Enlarge/magnified Inverted/upside down Virtual Choose lens S as objective lens Choose lens Q as eyepiece Lens S is placed in front of lens Q The two lenses are adjusted so that they are in normal adjustment where distance between the two lenses is equal to (fo + fe)

(ii) Modification 1. Use low power convex lens as the objective lens.

2. Use high power convex lens as the eye lens 3.Use bigger diameter of objective lens

Explanation - Magnification of telescope =

fo fe

,

∴ Low power lens has a longer focal length, fo ↑, magnification ↑ High power lens has a shorter focal length, fe ↓, magnification More light permitted to enter the telescope and a clearer image is seen

Question No. 22 (a) (i) Refraction (ii) Ratio of sin i / sin r // The ratio of speed of light in vacuum relative to that speed through a medium (b) Refractive index of the glass is higher. The density of glass is higher The angle of refraction of light ray in glass is shorter The higher the density of medium, the smaller the angle of refraction of light. The higher the density of medium, the higher the refractive index. (c)

(b)

(iii) wavelength produce by the two spherical dipper in diagram 10.1 is the same as in diagram 10.2 the distance between the two consecutive antinodes is greater in diagram 10.1 than 10.2 the distance between the two consecutive nodes is greater in diagram 10.1 than 10.2 increase in the distance between the two coherent source will decrease the distance between the two consecutive nodes or antinodes (i) sonar is a reflection from an ultrasonic waves. (ultrasonic echoes) ultrasonic wave has a higher frequency waves , it has more energy so it can move further it do not produce noise (iii) attach ultrasonic transmitter to a ship use a microphone receiver to detect ultrasonic pulses direct the ultrasonic pulses from the transmitter to the seabed use microphone receiver to pick up the reflected pulses from the seabed measure the time taken by the pulses to travel to the seabed and return calculate the depth of the water using the formula

d= (d)

v x t 2

Question No. 24 (a) (i) Refraction (ii) wave move from deeper to shallow area the wavelength decrease the speed decrease the direction of wave bends towards normal (b)

(i)

Characteristics Bay Concrete retaining wall High wall Smaller opening/ aperture / slit of retaining wall P

(ii) Modifications Objective lens with larger diameter. Eyepiece lens with higher power // Thicker eyepiece lens

Reasons More light passes through the lens Act as a strong magnifying glass

WAVES Question No. 23 (a) (i) Interference of waves (ii) wavelength depend on depth of water increasing/decreasing of depth will cause the wave to refract refraction will increase/decrease the length of wavelength the nodal/antinodal line will be affected

(ii)

Reason Wave is calmer Stronger/ / lasting Prevent high wave Diffraction obvious // low wave energy At bay, concrete retaining wall , high wall and smaller slit

(c)

(i) λ = 6

f = v

0.8 = 7.5 Hz V= λ f = 0.5 x 7.5 = 3.75 cm

Question No. 25 (a) (i) To ensure constant velocity of water wave / ripple. (ii) Interference (iii) Zero or minimum (iv) zero // minimum // smaller than the original amplitude (b) (i) The distance in Diagram 10.1 is higher (ii) The distance in Diagram 10.1 is smaller (iii) Same (iv) The higher the a, the smaller the x // a inversely Proportional (c) (i) Increase the number of loudspeakers // use more Loudspeakers

To produce louder sound // Sound transmitted covers a bigger (ii) Placed at all corners // different locations Cover a bigger area // the spectators around the area can hear clearly (iii) High amplification to produce louder sound // sound can travel further Large/big Less diffraction // spreading // sound travels straight Large/big Vibrates more air // produces louder sound Question No. 26 (a) When two crests or two troughs meet each other to form maximum amplitude (b) (i) Distance between two coherent sources in Diagram 10.2 is bigger than diagram 10.1 (ii) The wavelength are the same (iii) The distance between two adjacent antinodal lines in diagram 10.2 is smaller than diagram 10.1 (c) As the distance between two coherent sources increases, the distance between two adjacent antinodal lines decreases. (d) Refraction of light ray Light travels from less dense to a denser medium towards the normal / bending closer. In the observer eyes, the sun is still not setting as they can still see the image from refraction.

Suggestions Loudspeakers are positioned at quite a distance away.

The two main loudspeakers are not positioned opposite to each other Fix soft boards/ wooden/ materials which are sound absorbers Use thick carpet/ Wooden floor/ Rubber floor Assemble a high power speaker system Assemble the speaker at a high place

Reason So that the distance between consecutive constructive / destructive interference is smaller. To prevent multiple reflections

Reflection effects can be reduced

To prevent echo

To produce a high amplitude of sound wave

Wide coverage // the wave is not blocked

CHAPTER 7 Question No. 28 (a) Distance between focal pint and the optical centre of a lens (b) 1. The convex lens is aimed/focused to a distant object (infinity) 2. The screen is adjusted until a sharp image is formed on the screen 3. The distance between the screen and the lens is measured 4. Focal length = distance between the screen and the lens (c)

Aspect Longer focal length High magnification Distance = fo + fe

(e) Question No. 27 (a) A wave in which the vibration of particles in the medium is parallel to the direction of propagation of the wave (b)

(i)

(c)

(ii) The peak value, a2 in Diagram 10.2 is higher (iii) The higher the amplitude of vibration of tuning forks, the higher the peak value (iv) The higher the peak value, the louder the sound (v) The higher the amplitude, the louder the sound - Use ultrasound - Ultrasound is transmitted to the sea bed - a receiver will then detect the reflected the reflected pulses - the time taken by the pulse to travel to the seabed and return to the receiver being recorded, t - the depth of the sea can be calculated using the formula, d=

(d)

Bigger diameter J is chosen

The amplitude in Diagram 10.2 is higher

vt 2

(d) (i) 1 =1 + 1 f u v 1 = 1 – 1 v 5 400 v = 5.063 cm

Explanation To produce real, inverted and smaller image Produce bigger image Produce image at normal adjustment // image at infinity More light can enter objective lens // more brighter Longer focal length, higher magnification, Distance between two lenses = fo + fe and bigger diameter

(ii) h2 = v2 v1 h1 h2 = 5.063 100 400 h2 = 1.27 cm (iii) Real , inverted and diminished.

Question No. 29 (a) High melting point Can withstand high temperature / heat // does not melt easily Not easily oxidized Can last longer (b) (i) Maximum current flowing through the fuse is 0.5 A (ii) 1 Low melting point 2 Can melt easily 3 Low specific heat capacity 4 Can heat up easily 5 Small 6 High resistance // more heat released // easy to break 7 High 8 High resistance // more heat released 9 Z 10 Low melting point, low specific heat capacity, small diameter and high resistivity (c) (i) (ii) (iii)

500 240 = 2.08 A Not suitable 500 x (10x60) 300 000 J

Question No. 30 (a) A fuse is a very thin wire, which either melts or vaporizes when too much current flows through it (b) - A parallel circuit can run several devices using the full voltage of the supply. - If one device fails, the others will continue running normally - If the device shorts, the other devices will receive no voltage, preventing overload damage. - A failure of one component does not lead to the failure of the other components. - More components may be added in parallel without the need for more voltage. - Each electrical appliance in the circuit has it own switch. (c) (i) The electrical appliance use 240 V of voltage to generates 500 W of power. (ii) Current = Power/Voltage Current = 500/240 = 2.08 A (iii) Efficiency = Output Power x 100 % Input Power Output Power = 85 x 500 100 Output power = 425 W (d) Characteristics Explanation Thin fuse wire Less space needed/ to carry a limited electrical current/ less mass hence low heat capacity/ shorter time to heat up to melting point and blow. Ceramic cartridge

Fuse rating is 13 A Low melting point

R is chosen because

Can withstand higher temperature because sparks created by high voltage, 240V can be huge/ Maximum rating must be higher than normal current. For fast blow/ Melting faster when excessive current flow/ Easy to cut the current flow. Because it has thin fuse wire, ceramic cartridge, fuse rating is 13 A and low melting point.

CHAPTER 8 Question No. 31 (a) An electromagnet is a coil wrapped around a soft iron core which will be magnetized when a current flows through the coil and demagnetized when the current is switched off (b) Amount of iron filings attracted in Diagram 10.1 is smaller / less// amount of iron filings attracted in Diagram 10.2 is higher / more Current flow in Diagram 10.1 is smaller / less // current flow in Diagram 10.2 is higher / more Magnetic field strength in Diagram 10.1 is weaker // Magnetic field strength in Diagram 10.2 is stronger When the current is higher, the magnetic field strength is stronger, or vice versa When the magnetic field strength is stronger, the amount of iron filings attracted is more, or vice versa (c) When current flow through the solenoid, a magnetic field is produced The (soft) iron core will be magnetized The scrap metal attracted to the iron core When the current is switched off, the soft iron core will be demagnetised and the scrap metal falls down (d) Transformer step down To reduce the voltage from 240 V to 12 V The ratio of number of turns in primary coil to the number of turns in secondary coil is 240 : 12 // 20 : 1 To reduce the voltage from 240 V to 12 V Type of core is soft iron core // laminated iron core Soft iron core is easy to magnetized and demagnetized // Laminated iron core to reduce eddy current Diode is connected to the output To convert alternating current output to direct current Use copper wire Good electrical conductor // has low resistance // produce low heat Question No. 32 (a) Electrical energy light energy (b) (i) 1. When an a.c. voltage is supplied to the primary coil, the soft - iron core is magnetized 2. The magnet produced varies in magnitude and direction 3. This causes a changing magnetic flux to pass through the secondary coil 4. Induced e.m.f across the secondary coil is produced. (c) Aspect Explanation Soft iron core Easy to magnetized and demagnetised Laminated Less eddy current/ reduce energy lost Thick wire Reduce the resistance/more current Copper wire Low resistance/ reduce the lost of heat Q Soft iron core, Laminated , thick wire, Copper wire (d) (ii)

(i) 12 V Np = 240 x 200 = 4000 12 (iii) Efficiency = Po x 100 Pi = 240 x 0.2 x 100 = 100% 48

Question No. 33 (a) Magnet produce by current (b) (i) Current, I directly proportional to the number of paper clips attached, n The strength of electromagnet increases (ii) The magnitude of the current / number of batteries (dry cells) The use of soft iron core (c) High strength magnets Larger force acting on the coil High number of turns of coil Larger force acting on the coil / higher electromagnetic field strength Low density material Coil has smaller mass / lighter Using 4 diodes and a capacitor 4 diodes to produce full-wave rectification and capacitor as a smoother Y and high number of turns of coil, low density, high strength of magnets and 4 diodes and a capacitor. (d) (i) Aluminium (ii)

Question No. 35 (a) (i) Current produced when the magnetic flux is cut by conductor. (b) (i) No. of turns of the solenoid in Diagram 10.2 is greater. (ii) the deflection of the galvanometer pointer in Diagram 10.2 is bigger / larger. (iii) the rate of cutting of the magnetic flux in Diagram 10.2 is greater. (iv) Magnitude of induced current in Diagram10.2 is greater. (c) (i) No of turns increases, rate of cutting of magnetic flux increases. (ii) Rate of cutting increases, magnitude of induced current increases. (d) Faraday’s Law (e) (i) The greater the transmission voltage, the smaller the current in the power lines. Power loss during transmission due to resistance will be smaller. / P=I2R (ii) 1. laminated soft iron core 3. thick copper wire

240 30 =8Ω

(iii) 240 30

= 1920 W

Question No. 34 (a) (i) Step-down (ii) An alternating current flows through primary coil The soft -iron core is magnetized. The magnet produced varies in magnitude and direction. This causes a changing magnetic flux to pass through the secondary coil. An induced e.m.f across the secondary coil is produced. (b) I = 24/12 = 2A (with unit) Efficiency = Output power x 100 % Input power = 24 x 100 40 = 60W (c) Characteristics Thick

Reasons Reduce the resistance of the coil

Soft iron

Reduce the hysteresis loss// can be magnetized and demagnetized easily// Little energy used to be magnetized and demagnetized .

Laminated

Make the iron core as insulation. Eddy current are not able to flow through the layers of insulation// reduce eddy current

Low// Reduce leakage of magnetic flux near//shorter Choose P because copper wire thick, soft iron core, laminated core and distance is low.

5. the ratio of turns in primary coil to the number of turns in secondary coil is < 1 7. Wind the secondary coil on top of the primary coil 9. 2/4 diodes

2. to reduce the effect of eddy current 4. reduce heat loss due to resistance 6. to reduce output voltage to 18.5 V

8. to reduce the leakage of magnetic flux 10. to produce full-wave rectification

field lines Induced current flow in the coil. The current maximum when the coil cut the magnetic field at right angle // current decreased (become zero) when the coil move in parallel with magnetic field lines The direction of current flow determine by using Fleming’s right hand rule After 90o the direction of current in the external circuit reversed/ diagram

Question No. 36

(ii) Modification Change slip rings with commutator

Explanation To reverse contact with brushes so that the current flow in same direction in external circuit To increase the magnetic field strength Increase the rate of change of magnetic field/increase the induced current

Use stronger magnet Use more number of turn for the coil/ Increase the speed of rotation

TOPIC 9 Question No. 38 (a) Semiconductors are a group of materials that can be conduct electricity better than insulators but not as good as metal conductors (b) n- type semiconductor p-type semiconductor For n-type, majority charge-carries are electrons / minority charge-carries are positive holes but for p-type, majority charge-carries are positive holes / majority charge-carries are electrons For n-type, the doping substance is pentavalance but for p-type, the doping substance is trivalance (c) Characteristics The resistivity at 00C is low

Question No. 37 (a) (i) Electromagnet is a device in which magnetism is produced by an electric current // temporary magnet made by winding a coil round a soft iron core and magnetic field produce when current flow. (ii) Current flow in diagram 10.2 is more than 10.1 // vice versa. The amount of iron filing attracted by iron core in Diagram 10.2 is more than 10.1 // vice versa. The magnetic strength in diagram 10.2 is more than 10.1 // vice versa. Amount of iron filing attracted increase when current increase The magnetic field strength increase when current increase (b) When too high current flow, magnetic field strength become very strong / wire expand electromagnet pull the soft iron armature / pulled to the right by spring P. release the catch, contact separate and current does not flow When reset button is pressed, spring Q pulls the soft iron armature back to its original position (c) (i) When the coil rotates the coil cut across the magnetic

High melting point The valency of the doping substance are 3 and 5 Size of the atom of the doping substance is almost the same as the size of the substance

(d)

Explanation A current can flow through it more easily// Increasing the conductivity of the substance Not melting at high temperature Valency of 3 is used to make ptype semiconductor and valency of 5 is used to make n-type semiconductor Can maintain the crystal-line structure of the substance// Give good effect in the doping process

Substance Q is chosen Because Q has low resistivity at 00C, high melting point, valency of the doping substance is 3 and the size of the doping substance is almost the same as the size of the substance (i) Thermionic emission (ii)

Velocity of the electron,

v =

eV

=

1 2 mv 2

2 x 1.6 x 10 −19 x 4000 9.1 x 10 −31

= 3.75 x 107 m s-1

(b)

Question No. 39 (a) Doping is a process of adding a certain amount of specific impurities to semiconductors to increase their conductivity (b) Diagram 10.1, the p end of diode is connected to negative terminal of dry cell // Diagram 10.2 the p end of diode is connected to positive terminal of dry cell Bulb in Diagram 10.1 does not lights up No current flow in Diagram 10.1 // Current flow in Diagram 10.2 The bulb will lights up when the p end of diode is connected to the positive terminal of dry cell // vice versa Current only flow in the circuit when p end of diode is connected to positive terminal of dry cell or in forward bias (c)

(i) (ii)

(d)

1 2 3 4 5 6 7 8 9 10

Draw correct symbol and correct direction Draw smooth waveform Capasitors store charge when current flow Capasitor discharge when current does not flow LDR is replace by termistor / diagram resistance decrease when temperature increase Termistor is place at R1 and R1 replace LDR / diagram So that V across R1 increase when the room is hot Relay switch replace LED To switch on secondary circuit /to switch on the fan Fans are arranged parallel All fans received 240 V power supply / other fans still functioning even though one fan did not function Resistor connected to the base of transistor limit the current to the transistor

Question No. 40 (a) (i) Circuit consists transistor, resistor and cell (ii) 10.1 : Microammeter no reading // 0 A, milliammeter no reading // 0 A (iii) 10.2 : Microammeter has a reading // 1 x 10-6 A , milliammeter has a reading // 1 x 10-3 A (iv) Change in microammeter reading small, change in milliammeter reading is bigger Ib Increase, Ic increase // Ic depends on Ib A small change in Ib caused a big change in Ic (b) At night resistance LDR increases VBE increases Ib increases and switch on transistor Ic increases and lights up bulb (c) Modification Replace LDR with termistor Replace bulb with siren / bell

(i)

(ii) connect a capacitor in parallel to the output (iii)

(iv)

(c)

(d)

(i) current a.c (ii) 4V (iii) T = 4 x 0.1 =0.4s Frequency, f = 1/T = 1/0.4 = 2.5 Hz (iv)

Explaination To detect heat when temperature is high To produce sound

Connect relay switch to output transistor Interchange the position of resistor R and termistor

To switch on the siren

Use 240 V power supply

Siren is function at high voltage

To increase base voltage / / voltage across R // base current

Question No. 41 (a) Semiconductor is a material with electrical conductivity better than an insulator but weaker than a conductor.

Question No. 42 (a) Unstable isotopes which decay and emit radioactive particles / ray (b) Radioisotope is injected into the pipe G-M tube as detector is used to find the leakage Reading on detector increases when near a leakage (c) 1. type of ray is 2. high penetration power gamma can penetrate through the pipes 3. short half life 4. Decay faster and detection can be done faster 5. in liquid state 6. Easy to flow/ dissolve

(d)

(i)

136

(ii)

Question No. 44 (a) Radioisotopes are isotopes which have unstable nuclei. (b) Characteristics Has a long half-life

(iii)

(e)

(i) (ii)

3 alpha 2 beta Source L

Emits beta

Solid form Low ionising power 20 min-1

Radioisotope T

Question No. 43

(c)

(i) (ii)

(d)

Explanation Can be used for a long time hence save cost Can penetrate box and liquid and is less dangerous than gamma Easy to handle and contain. Does not change the state and taste of juice. It has long half life, emits beta, in solid form and has low ionising power.

Geiger Muller Tube Bottle E Rate meter reading is the highest Most radiation can reach the detector without being block by juice Correctly stated that α as

4 2

Correctly stated that β as

0 −1

Working is shown X=3 Y=2

He e

Physics p2 Essay

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