2015 PSPM Kedah Fizik2 w Ans

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MODUL PENINGKATAN PRESTASI TINGKATAN 5 TAHUN 2015 MAJLIS PENGETUA SEKOLAH MALAYSIA (KEDAH)

MODUL 2

FIZIK Kertas 2 Peraturan Pemarkahan

1

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BAHAGIAN A Soalan 1(a) (b) (c) (i) (ii) 2(a) (b) (c) (d)

3(a) (b)

(i) (ii) (i) (ii) (i)

Cadangan Jawapan longitudinal wave reflection No change Decreases Latent heat Does work to break the bonds between the molecules // Weaken the forces of attraction between molecules does not change Q1 is smaller than Q2 Work is done to increase the distance between the molecules

Markah 1 1 1 1 4 1 1

Correct shape 2 complete cycles

1 1 1 5 1 1 1 1

4 complete cycles peak value doubled

1 1

direct current 

(ii)

4(a) (b)

(i)

(ii) (iii) (c)

5(a) (b)

(c)

6(a) (b)

(i) (ii) (i) (ii) (iii) (i) (ii)

(i) (ii) (iii) (iv)

(c) (d)

(i) (ii)

Ratio of the potential difference to the current 1.4 1.2 1.17 Ω Increases filament lamp 1.25 × 1.5 1.875 W Decreases The number of unstable atoms is decreasing // The graph has a negative gradient 20 hours 2 hours Y The shorter the half-life, the faster the rate of decay. X Longer half-life / slower rate of decay gives enough time to locate the leakage Degree of hotness of an object The initial temperature of the water in Cup X > cup Y Cup X : Temperature decreases with time Cup Y : Temperature increases with time Cup X : Heat is is released to the surroundings surroundings Cup Y: Heat is absorbed from the surroundings When the temperature of an object decreases, heat heat is transfered from the object to the surroundings // When the temperature of an object increases, heat is transfered from the surroundings to the object Thermal equilibrium Shorter time Cooking oil has a smaller specific heat capacity

2

6 1 1 1 1 1 1 1 7 1 1 1 1 1 1 1 1 8 1 1 1 1 1

1 1 1 8

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Soalan 7(a) (b)

(c)

(i) (ii) (iii)

8(a) (b) (c)

(i) (ii)

(d)

(e)

(i)

(ii)

(iii)

Cadangan Jawapan The exhaust gases move downwards with a large momentum The rocket gains an equal momentum upwards 1 2 2 0 = 15  + 2(-10) h // m × 10 × h =  × m × 15 2 h = 11.25 m Aerodynamic // Streamline Reduce air resistance High Larger upward thrust / force // Higher water speed Fins near the tail of the rocket Prevent the rocket from spinning Interference Increases Oscillates up and down with a large amplitude Constructive interference occurs at P Distance increases Speed of the waves increase Wavelength is longer In front of the microphone Avoid disturbance // to prevent the sound from speakers being amplified again by the microphones Further distance between the speakers So that positions of constructive and destructive interference are closer together until they are hardly noticeable. S

3

Markah 1 1 1 1 1 1 1 1 1 1 10 1 1 1 1 1 1 1 1 1 1 1 1 12

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BAHAGIAN B Soalan 9(a) (b) (i)

(ii) (iii) (iv) (c)

Cadangan Jawapan Depth // density // acceleration due to gravity Size : P < Q Depth : P > Q Pressure : P > Q The bigger the depth, the smaller the size of the air bubble The bigger the depth, the higher the pressure on the air bubble The higher the pressure, the smaller the volume When the volume of a gas is decreased, the same number of molecules move in a smaller space. The molecules collide more frequently with the walls of the bubble. A larger force acts on the walls of the bubble. Therefore pressure increases.

Markah 1 1 1 1 1 1 1 1 1 1

(d) Aspect Attire

Extra equipment Gas tank

Suggestion Water proof // Tight fitting

Explanation Does not become wet // Does not absorb water // Less water resistance Help the diver to swim under water Smaller weight // Smaller load for the diver to carry

Flippers Light material

Smaller size

1+1 1+1 1+1 1+1

Reduces the weight of the tank 1+1

Contains oxygen rich air at high pressure

Diver can stay longer under water

Note : Extra equipment includes mask, pressure gauge, dive watch, dive light, buoyancy control device, signalling device etc 20

4

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Soalan 10(a) (b)

(c)

(i) (ii)

Cadangan Jawapan A substance that has a conductivity between the conductivity of an insulator and a conductor / metal To increase the conductivity // To reduce the resistivity Doping with boron produces a p-type semiconductor Majority charge carriers are holes Doping with phosphorus produces a n-type semiconductor Majority charge carriers are electrons During the first half cycle : the resistance of the diode is low a current flows in the circuit // the diode is forward biased During the next half cycle : the resistance of the diode is very high no current flows in the circuit // the diode is reverse biased

Markah 1 1 1 1 1 1 1 1

1 1

(d) thermistor replaces the resistor resistor replaces the LDR bell replaces the bulb complete circuit

When the surrounding is hot : the resistance of the thermistor decreases the potential difference across the thermistor decreases the potential difference across the resistor increases the base current increases the transistor is switched on the collector current flows

1 1 1 1

1 1 1 1 1 1 20

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BAHAGIAN C Soalan 11(a) (i) (ii)

Cadangan Jawapan Image that cannot be formed on a screen Object between lens and F Rays parallel to principal axis passing through F Ray passing through optical centre Image F

Markah 1 1 1 1 1

F O

I

(b) Aspect Cooling fan

Suggestion Larger diameter

Power of lamp

Higher power

Orientation of coloured glass Distance between the coloured glass picture and the projector lens

(c)

(i)

Inverted Between f  and  and 2 f

1+1

1+1 1+1 1+1

X is the most suitable - cooling fan with large diameter - high power lamp - inverted coloured glass picture - coloured glass picture at a distance between f  and  and 2 f

1

v = 36

1

1  f 

=

1 12

+

1

1 1

36

 f  =  = 9 cm

(ii)

Explanation Bigger volume of air to cool the lamp More light energy to produce a brighter image To produce an upright image on the screen To produre a real and magnified image

1 1

36 12 3

1 20

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Soalan 12(a) 12(a) (i)

(b)

(ii)

Cadangan Jawapan The production of an electromotive force / current in a conductor when it cuts magnetic flux The alternating current in the primary primary coil produces a changing changing magnetic magnetic field The magnetic field cuts the secondary coil The secondary coil has less turns than the primary coil A smaller voltage is induced across the secondary coil

(i)

V S V P

=

V S

240

Markah 1 1 1 1 1

 N S  N P

=

80

1

3200

V S = 6 V The output voltage of the transformer is less than the operating voltage of the bulb (ii)  I P V P = I S V S  I P × 240 = 0.75 × 12  I P = 0.0375 A

1 1 1 1

(c) Aspect Resistivity Core

Suitability Low 8-shape

Winding of coils

Primary and secondary coil over HK More thin layers

Lamination of core

S is the most suitable - low resistivity - 8-shape core - Primary and secondary coil over HK - More thin layers of soft iron lamination

Explanation Lower the rate of heat loss Magnetic field produced by the primary passes completely through the secondary Less leakage of magnetic flux Reduces eddy currents

1+1 1+1

1+1 1+1 1

1 20

7