Cent Centre re Numb Number er
Candidate Numb Number er
Candidate Name
UNIVERSITY OF CAMBRIDGE LOCAL EXAMINATIONS SYNDICATE General Certificate of Education Ordinary Level
5054/2
PHYSICS PAPER 2 Theory Tuesday
8 JUNE 1999
Afternoon
1 hour 45 minutes
Candidates answer on the question paper. Additional materials: Answer paper Electronic calculator and/or Mathematical tables Graph paper Ruler 300 mm
TIME
1 hour 45 minutes
INSTRUCTIONS TO CANDIDATES Write your name, Centre number and candidate number in the spaces at the top of this page and on any separate answer paper used. Section A Answer all questions. Write your answers in the spaces provided on the question paper. pap er. Section B Answer any two questions. Write your answers on the lined pages provided and, if necessary, continue on the separate answer paper provided. At the end of the examination, 1.
fasten fasten any separate separate answer answer paper paper used securely securely to the question question paper paper,,
2.
enter the numbers numbers of the Section Section B question questions s you have have answered answered in the the grid below below..
INFORMATION FOR CANDIDATES The number of marks is given in in brackets [ ] at the end of each question or part question. Candidates are reminded that all quantitative answers should include appropriate units. Candidates are advised to show all their working in a clear and orderly manner, as more marks are awarded for sound use of physics than for correct answers.
FOR EXAMINER’S USE Section A Section B
TOTAL
This question paper consists of 15 printed pages and 5 lined pages. MML LOC 926 5/98 QF92358 © UCLES 1999
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Section A Answer all the questions in this section.
1
Fig. 1.1 shows the variation variation with time t of the speed of a stone that is thrown vertically downwards. In this question, air resistance re sistance may be ignored. 6 speed m/s
5 4 3 2 1 0
0
0.05 0.05 0.10 0.10 0.15 0.15 0.20 0.20 0.25 0.25 0.30 0.30 0.35 0.35 t /s Fig. Fig. 1.1
The stone has mass 0.23 kg and leaves the thrower’s thrower’s hand at t = 0. It hits the ground at t = t = 0.325 s and rebounds with 50% of the speed with which it hit the ground. (a) State the maximum speed of the stone. maximum speed = ..................................... [1] (b) Show, using data from Fig. 1.1, that the acceleration of free fall is 10 m/s2.
[2]
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(c) Determine the speed of the stone just after it rebounds.
speed = ..................................... [1] (d) Calculate the loss of kinetic energy of the stone as it hits the ground and rebounds.
loss of kinetic energy = ...................................... [3]
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2
A person standing at point A in Fig. 2.1 sees the reflection in a shop window of a person standing at point B. B
wall
A
shop window
Y
wall
Fig. Fig. 2.1 (a) On Fig. 2.1, draw a ray of light to show how, how, by reflection, the person pe rson at A sees the person at B. [1] (b) On Fig. 2.1, mark, with with a letter I, the position of the image of B formed by reflection in the shop window. [2] (c)
(i) The person at A moves further away from B towards Y in the direction of the arrow shown in Fig. 2.1. Mark with a letter X the furthest position along AY AY to which the person can move so that the two people will still be able to see each other by reflection in the shop window. (ii) Explain how you decided on the position of X. .................................................................................................................................. .................................................................................................................................. .................................................................................................................................. [2]
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3
The chart in Fig. 3.1 shows the main parts of the electromagnetic spectrum. visible
gamma rays
10–12 m
X-rays
ultra-violet
10–9 m
infra-red
10–6 m
radio
10–3 m
1m
1000 m wavelength
Fig. Fig. 3.1 (a) All of the different types of electromagnetic waves in the chart may be reflected. State three other properties common to all electromagnetic waves. 1. ...................................................................................................................................... 2. ...................................................................................................................................... 3. ..................................... ......................................................................... ......................................................................... ....................................................... .................. [3] (b) Microwav Microwaves es travel travel at a speed of 3.0 x 108 m/s in a vacuum and have a frequency of 1.5x1010 Hz. (i) Calculate the wavelength of these microwaves.
wavelength = ..................................................... .................................. ................... (ii) On the chart in Fig. 3.1, mark a line to represent the position of these mi microwav crowaves es in the electromagnetic spectrum. [3]
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4
Fig. 4.1 shows three combinations of resistors, connected between points X and Y. Y. All the resistors have resistance 6.0 . X
X 6.0
X 6.0
6.0
6.0 6.0
6.0
6.0
6.0
6.0 Y
Y
combination A
Y
combination B
combination C
Fig. Fig. 4.1 (a) Calculate the total resistance between the points X and Y of each combination. (i) combination A
total resistance of combination A = ...................................................... (ii) combination B
total resistance of combination B = ...................................................... (iii) combination C
total resistance of combination C = ...................................................... [4]
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(b) Points X and Y in combination B are connected to a battery that provides a potential difference of 1.35 V across XY, XY, as shown in Fig. 4.2. Calculate the currents I 1, I 2 and I 3 in each resistor of the combination. X I 1
6.0 I 2
I 3
1.35 V 6.0
6.0
Y Fig. Fig. 4.2
I 1
=...................
I 2
=...................
I 3
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=...................
[3]
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5
Two vertical metal plates are connected to a high voltage power supply, as shown in Fig. 5.1. An electric field exists in the space between the plates.
plate
plate
+
–
power supply Fig. Fig. 5.1 (a)
(i) State what is meant by the electric field between field between the plates. .................................................................................................................................. .................................................................................................................................. (ii) On Fig. 5.1, draw lines of force force to show the electric field between the two plates. [3]
(b) An uncharged metal ball is hung by an insulating thread between the two plates, as shown in in Fig. 5.2.
+
–
power supply Fig. Fig. 5.2 On Fig. Fig. 5.2, (i) draw the distribution of charge that will be found on the metal ball, (ii) draw lines of force to show the new electric field between the plates. [2] 5054/2/S99
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6
Fig. 6.1 is a diagram of a d.c. motor. motor. pivot coil
magnet pole
N
B
S C
magnet pole
A D
current
carbon brush
carbon brush
split-ring commutator
Fig. Fig. 6.1 (a )
(i) State the direction of movement of side AB and of side CD when the current is in the direction direction shown in Fig. 6.1. side AB .............. ...................... ............... .............. .............. .......... ...
side CD .............. ..................... .............. ............... ............... ........... ....
(ii) Explain the reason for your choices of direction. .................................................................................................................................. .................................................................................................................................. .................................................................................................................................. [3] (b) When the coil ABCD is vertical, the brushes line up with the gaps in the split-ring commutator. The coil rotates past the vertical position. Explain what happens (i) to the current in the coil, .................................................................................................................................. .................................................................................................................................. (ii) to the forces on the sides AB and CD of the coil. .................................................................................................................................. .................................................................................................................................. [2] 5054/2/S99
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7
Explain, by writing about molecules, (a) how the air inside a car tyre exerts a pressure on the walls of the tyre, .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... ........................................................................ ................................... .......................................................................... ............................................................ ....................... [2] (b) why the pressure in the car tyre increases as the tyre becomes hotter, .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... ........................................................................ ................................... .......................................................................... ............................................................ ....................... [2] (c) why the pressure in the tyre increases as more air is pumped into the tyre. .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... ........................................................................ ................................... .......................................................................... ............................................................ ....................... [1]
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8
Fig. 8.1 shows a car moving along a horizontal road. air resistance forward driving force
friction
Fig. Fig. 8.1 The car has mass 800 kg. At one point in its motion, when the combined forces of air resistance and friction acting backwards are 400 N, its acceleration acceleration is 1.4 m/s2. (a) Calculate the forward driving force required to accelerate the car.
forward driving force force = ....................................... ................................. ...... [3] (b) With the engine working at constant full power, the car’s acceleration decreases as it goes faster. faster. Explain why this is so. .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... ....................................................................... .................................. .......................................................................... ............................................................. ........................ [2]
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12 Section B Answer two questions from this section. Use the lined pages provided and, if necessary, continue on the separate sheets she ets available from the Supervisor.
9
Fig. 9.1 shows the apparatus used used by a student to measure the specific latent latent heat of vaporisation of water. A heater is placed into a beaker of water which stands on top of electronic weighing scales so that the mass of the beaker and water may be measured. power supply
insulation beaker water
heater
electronic weighing scales
g Fig. Fig. 9.1 In this question, you may assume that there is no heat lost to the atmosphere. (a) Define what is meant by the specific latent heat of vaporisation o vaporisation of water.
Question 9 is continued on page 13.
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[3]
13 (b) As soon as the water is boiling, the student notes down the reading on the scales and starts a timer. Every 100 seconds the student notes down the reading on the scales. The results obtained are shown in the table.
time/s
0
reading reading on on scale scale / g
203.22
100
200
300
400
201.62
199.79
198.26
196.50
(i) Draw up a table table to show the total total mass of water water evaporat evaporated ed after 100 s, 200 s, 300 s and 400 s. That is, from from 0 to 100 100 s, 0 to 200 200 s and so on. on. (ii) The heater supplies energy at the rate of 38 J/s. Add to your table table values showing the energy provide provided d by the heater heater in 100 100 s, 200 s, 300 s and 400 s. That is, from from 0 to 100 s, 0 to 200 s and so on. on. [2] (c) Plot a graph of energy supplied (y (y -axis) -axis) against mass of water evaporated (x (x -axis). -axis). Star t your axes at (0,0).
[4]
(d) Determine the gradient of your graph. How is the specific latent heat of vaporisation of water related to this gradient? [3] (e) The voltage of the power supply connected to the heater is doubled. Describe and explain the effect this has on the readings obtained, and on the final result. [3]
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14 10 Fig. 10.1 illustrates nuclear fission of Uranium-235 Uranium-235 in a nuclear reactor. reactor.
neutron U-235 nucleus
before fission
after fission Fig. Fig. 10. 10.1 1
(a)
(i) Describe the process illustrated in Fig. 10.1. (ii) Describe how the process of nuclear fusion differs from the process of nuclear fission as illustrated above. [5]
(b) The waste products from a nuclear reactor contain isotopes such as Iodine-131 and Caesium-137. These waste products are highly radioactive and dangerous. They are stored in sealed metal cans which wh ich are placed under water for a few months. (i) Explain how these isotopes were produced. (ii) Explain what is meant by the term radioactive . (iii) Give a reason why metal cans are used and a reason why they are placed under water. [5] (c) Radioactive isotopes are used in medicine and in industry. Describe and explain one use that is made of a radioactive isotope. In your account, indicate whether the isotope should have a long or a shor t half-life. [5]
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15 11 (a) Fig. 11.1 shows the maximum daytime daytime and minimum night-time surface temperatures of a region of land and sea during a 24 hour period.
30 C °
sea
5 C °
land
18 C °
sea daytime
land
17 C °
night-time Fig. 11. 11.1 1
(i) The temperatures shown cause the air above the land and sea to move. Describe the movement of the air during the daytime and during the night-time. Explain in detail why the air moves in the way that you describe. Include a diagram of the air movements in your account. (ii) Explain why the surface temperatures of the land and sea both drop during the nighttime, and why the surface temperature of the land falls more than the surface temperature of the sea during the night. [9] (b) Black surfaces emit and absorb more infra-red radiation than white surfaces when both are at the same temperature. Describe how you would demonstrate that (i) black surfaces absorb more radiation than white surfaces, (ii) black surfaces emit more radiation than white surfaces at the same temperature. [6]
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Copyright Acknowledgements: Acknowledgements: Question Question 6. Fig.6.1.
© To follow. follow. 5054/2/S99
