paper 2 nov 1999 physics
TRANSCRIPT
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 onany separate answer paper used.
Section A
Answer all questions.
Write your answers in the spaces provided on the question paper.
Section B
Answer any two questions.
Write your answers on the lined pages provided and, if necessary, continue on the separate answerpaper provided.
At the end of the examination,
1. fasten any separate answer paper used securely to the question paper,
2. enter the numbers of the Section B questions you have answered in the grid below.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets [ ] at the end of each questionor part question.
Candidates are reminded that all quantitative answers should includeappropriate units.
Candidates are advised to show all their working in a clear and orderlymanner, as more marks are awarded for sound use of physics than forcorrect answers.
This question paper consists of 15 printed pages and 5 lined pages.MML LOC 926 5/98 QK94122© UCLES 1999 [Turn over
CandidateCentre Number Number
Candidate Name
UNIVERSITY OF CAMBRIDGE LOCAL EXAMINATIONS SYNDICATEJoint Examination for the School Certificateand General Certificate of Education Ordinary Level
PHYSICS 5054/2PAPER 2 Theory
Thursday 11 NOVEMBER 1999 1 hour 45 minutes
Candidates answer on the question paper.Additional materials:
Answer paperElectronic calculator and/or Mathematical tablesGraph paperProtractorRuler 300 mm
FOR EXAMINER’S USE
Section A
Section B
TOTAL
Section A
Answer all the questions in this section.
1 A toy car is given a brief initial push which sends it along a horizontal section of runway.The force of gravity then accelerates the car down the ramp which is shown in Fig. 1.1. In this question the only force due to friction that acts on the car is air resistance.
Fig. 1.1
(a) On Fig. 1.1, where the car is moving down the ramp at A, draw labelled arrows to show
(i) the direction of the force due to gravity on the car,
(ii) the direction of the force due to friction on the car.[1]
(b) State the effect that friction has on the motion of the car
(i) while the car is moving along the horizontal section,
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(ii) while the car is accelerating down the ramp.
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0.90 mhorizontal section
A
ramp
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(c) The length of the ramp is 0.90 m and the average force of friction is 0.11 N.
(i) Calculate the work done by the car against friction as it moves down the ramp.
work done = ......................................
(ii) The car has 0.30 J of kinetic energy at the top of the ramp and loses 0.50 J ofpotential energy as it moves from the top to the bottom of the ramp.
Calculate the kinetic energy of the car at the bottom of the ramp.
kinetic energy = ......................................[4]
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2 Fig. 2.1 illustrates the arrangement of molecules of a substance in different states of matter.
Fig. 2.1
(a) State which arrangement A, B or C represents the structure of
the solid, ..........................................
the liquid, ..........................................
the gas. .......................................... [1]
(b) Explain why the density of the gas is lower than that of the solid.
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(c) Describe the movement of the molecules in
(i) the solid, ...................................................................................................................
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(ii) the liquid, ..................................................................................................................
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(iii) the gas. .....................................................................................................................
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CBA
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3 Fig. 3.1 shows a light aluminium rod resting between the poles of a magnet. A current ispassed through the rod from two brass strips connected to a power supply.
Fig. 3.1
(a) On Fig. 3.1, draw the direction of the current in the rod when the switch is closed. [1]
(b) State which way the rod moves when the switch is closed. Give a reason for your answer.
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(c) State the effect on the movement of the rod when
(i) the current is increased,
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(ii) the current is reversed.
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N
Sbrass strip
brass strip
switch (open)
aluminium rod magnet
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4 Answer EITHER (a) OR (b). Do NOT answer both (a) and (b).
EITHER
(a) The circuit shown in Fig. 4.1 acts as a light sensitive switch.
Fig. 4.1
The component X is a light dependent resistor (LDR). The connections to the buzzerand to the switch Y inside the relay have not been drawn. Switch Y is shown open inFig. 4.1.
(i) On Fig. 4.1, draw the connections to the buzzer, the switch Y and the cell that willallow the buzzer to sound when the switch Y inside the relay closes.
(ii) Complete the table below stating
1. whether the resistance of the LDR is high or low in the light and in the dark,
2. whether the current through the relay coil is high or low in the light and in thedark.
[4]
relay buzzer
X
Y
coil
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light
resistance of LDR current through relay coil relay switch Y
closed
open
buzzer
ON
OFFdark
OR
(b) (i) State the names of the logic gates shown in Fig. 4.2.
Fig. 4.2
logic gate A ....................................... logic gate B ........................................
(ii) Describe the difference in the action of the two logic gates when HIGH (1) andLOW (0) signals are applied to their inputs.
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inputsoutput
A
inputsoutput
B
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5 Some electrical components are easily damaged if electric charge is placed on them. Theyare often stored by placing them in contact with a conductor.
(a) When the component shown in Fig. 5.1 is rubbed with a cloth, the metal legs becomenegatively charged. Explain how this happens.
Fig. 5.1
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.................................................................................................................................... [2]
(b) Fig. 5.2 shows the negatively charged metal legs placed near a piece of aluminium foilwhich rests on an insulator.
Fig. 5.2
(i) On Fig. 5.2, draw the induced charges that form on the aluminium foil.
(ii) The metal legs are placed in contact with the aluminium foil. Describe whathappens to the charges on the foil and on the legs.
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––
––
––
––
plastic
metal leg
aluminium foil
insulator
plastic
metal legs
electrical component
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6 Fig. 6.1 shows part of the lighting circuit of a house.
Fig. 6.1
(a) (i) Explain why a fuse is included in the circuit.
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(ii) Explain why the fuse is placed in the live wire rather than in the neutral wire.
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(b) Each lamp has a power of 60 W. Calculate the current through one lamp when it isswitched on.
current = ...................................... [2]
(c) The fuse has a rating of 5 A. Calculate the maximum number of lamps that can beconnected and switched on without the fuse blowing. Each lamp is in parallel with thepower supply.
maximum number of lamps = ...................................... [2]
live
neutral
230 V
fuse 5 A
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7 A radioactive source and a detector are used to check the level of fruit juice in a carton.Cartons of fruit juice pass between the detector and the radioactive source, as shown inFig. 7.1. The radioactive source emits �-particles.
Fig. 7.1
(a) State the name of a suitable detector of the �-particles.
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(b) What is a �-particle?
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(c) Explain why the level of detected radiation falls when a full carton of juice goes pastthe detector.
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(d) Explain
(i) why a source emitting �-particles is not used,
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(ii) why a source emitting �-rays is not used.
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fruit juicecarton
radioactive source
radiationdetector
conveyorbelt
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8 A small quantity of solid wax in a test-tube is heated slowly. Fig. 8.1 shows the variationwith time of the temperature of the wax.
Fig. 8.1
(a) (i) State what is meant by the melting point of a substance.
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(ii) Determine the melting point of the wax in the experiment.
melting point = ......................................[3]
(b) In a second experiment, twice the amount of wax is used, and exactly the sameamount of heat energy every second is passed into the wax as in the first experiment.The initial temperature of the wax is also 30 °C.
On Fig. 8.1, draw the variation with time of the temperature of the wax in this secondexperiment. You may assume that the heat needed to warm up the test-tube itself isnegligible. [2]
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20
30
40
50
60
70
80
90
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
temperature°C
time/min
Section B
Answer two questions from this section.
Use the lined pages provided, and, if necessary, continue on the separate sheets available from the Supervisor.
9 A student performs an experiment to demonstrate the refraction of light by a rectangular glassblock. Fig. 9.1 shows, to scale, the outline of the glass block and the paths of the incident andemergent rays that the student draws on a piece of paper.
Fig. 9.1
(a) Describe the apparatus needed and also a method by which the paths of the incident andemergent rays may be drawn on a piece of paper. [3]
(b) Take measurements from Fig. 9.1 to find the refractive index of the glass block. Show clearlyyour working, state the equation that you use and give your answer to an appropriatenumber of significant figures. [3]
emergentray
incidentray
glass block
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(c) The student repeats the experiment with the incident ray at different angles. The valuesobtained for the angles x and y shown in Fig. 9.2 are given in the table.
Fig. 9.2
Plot a graph of y / ° (y-axis) against x / ° (x-axis). Your axes should end at y / ° = 50 and x / ° = 90.
Draw the best curved line through your points. [4]
(d) (i) Use your graph to estimate the critical angle for glass and explain how you obtainedyour result.
(ii) Explain why it is impossible to obtain a value of y = 50° in this experiment.[3]
(e) The glass block used in the experiment is replaced by one having a larger refractive index.The experiment is repeated and a second graph is plotted. State one similarity and onedifference between this second graph and the graph obtained in (c). [2]
y
x normal
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x / °
y / °
0
0
10
7
20
13
30
20
40
26
50
31
60
36
70
39
80
42
10 An engineer wishes to check the volume of air inside a pipe and to check that the pipe is notleaking. He connects a syringe to one end of the pipe and a manometer to the other end, asshown in Fig. 10.1.
Fig. 10.1
The syringe initially contains 60 cm3 of air, and the pipe contains 5000 cm3 of air. The volume ofthe narrow tubes may be neglected. All the air is initially at atmospheric pressure, 1.000 x 105 Pa.
The piston is pushed fully down and held steady so that the total volume of air decreases.
(a) Explain, in terms of molecules, why the pressure of the air inside the pipe increases whenthe piston in the syringe is pushed down. [3]
(b) In this section, assume the pipe does not leak and that the temperature of the air insideremains constant.
When the piston is pushed fully down, calculate
(i) the new pressure of the air in the pipe,
(ii) the difference in pressure between the air inside and the air outside the pipe,
(iii) the depth of water which exerts the same pressure as your value in (ii).[density of water = 1000 kg/m3; g = 10 N/kg]
[7]
(c) (i) If the pipe leaks very slowly, state what happens to the levels of water on each side ofthe manometer when the piston is pushed down and left down. Draw a diagram of themanometer to illustrate your answer.
(ii) State how the manometer could be altered to give larger differences in liquid level forthe same pressure in the pipe.
[5]
0
60
cm3
air volume 5000 cm3
syringe
pipe
manometer
narrow tubenarrow tube
water
air
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11 Ultrasound and X-rays are both used to provide information about structures inside the humanbody. Ultrasound is sound having a frequency above the highest audible frequency that humanscan hear. X-rays are a region of the electromagnetic spectrum with a higher frequency thanvisible light.
Fig. 11.1
(a) (i) Name three regions of the electromagnetic spectrum other than X-rays and visible light.
(ii) Copy Fig. 11.1 and on it show the position of the three regions of the electromagneticspectrum that you have chosen in (i).
(iii) Write one or two sentences about each region of the spectrum that you have chosen,describing how the electromagnetic waves are used or how they affect people.
(iv) State one property that all parts of the electromagnetic spectrum have in common.[8]
(b) Fig. 11.2 shows ultrasound being used to study an unborn baby.
Fig. 11.2
(i) Explain how the vibrations of the source produce waves of ultrasound and suggest howthese waves are transmitted through the body tissue to the receiver.
(ii) Ultrasound used in medicine has a frequency which is about 100 times higher than themaximum frequency that can be heard by humans.
Estimate the frequency that might be used for ultrasound in medicine, and calculate itswavelength in the human body. The speed of ultrasound in the human body is 1500 m/s.
[7]
ultrasoundreceiver
ultrasoundsource
ultrasoundbeam
increasing frequency
X-raysvisiblelight
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