Paper 4 Nov 1999 Physics

Centre Number

Candidate Number

I

Candidate Name

UNIVERSITY OF CAMBRIDGE LOCAL EXAMINATIONS SYNDICATE Joint Examination for the School Certificate and General Certificate of Education Ordinary Level

5054/4

PHYSICS PAPER 4 Alternative to Practical Thursday

4 NOVEMBER 1999

1 hour

Candidates answer on the question paper. Additional materials: Electronic calculator and/or Mathematical tables Protractor Ruler (300 mm)

TIME

1 hour

INSTRUCTlONS TO CANDIDATES Write your name, Centre number and candidate number in the spaces at the top of this page. Answer all questions. Write your answers in the spaces provided on the question paper.

INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question.

I

FOR EXAMINER’S USE

This question paper consists of 11 printed pages and 1 blank page. SB (SLC/JB) OK94127/3 0 UCLES 1999

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For 'xammer's Use

2 1

Fig. 1.1 represents a ray-tracing experiment which uses a transparent prism.

(a) (i) The path of an incident ray, which meets the face of the prism at I, is marked by the points 0 and P. On Fig. 1.1, draw the line that represents the incident ray and continue this line to meet the right hand edge of the page. Label this line 'incident ray'. PI (ii) The path of the emergent ray, which emerges from the prism surface, is marked by the points Q and R. On Fig. 1.1, draw the line which represents the emergent ray. Produce this line backwards and draw it to meet the top of the page. Label this line 'emergent ray'. [11

(iii) Label the point of intersection of your two lines with the letter D. The smaller angle between the two lines is know as the angle of deviation d. Measure both of the small angles and so obtain a value for the angle of deviation d.

d = .....................................

[31

(b) Suggest a reason why you were asked to draw long lines after the intersection at D.

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P' I

.R

Fig. 1.1

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2

The Physics class is experimenting with diodes using the circuit shown in Fig. 2.1

Fig. 2.1 (a) The potential difference across the cell is 2 V and the variable resistor VR is used so as to act as a potential divider.

(i) In Fig. 2.1, switch S , is shown open. This switch is now closed and the potential divider (VR) is set with the sliding contact at position X. What is the reading Von the voltmeter V,? reading on V, is V=

.....................................

PI

(ii) The teacher said that it is a good procedure to put the sliding contact at position Y before closing the switch S,. Explain why this is a good procedure.

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(b) (i) Switch S, and switch S, are now closed. Although the position of the slider on VR

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is changed, the reading on V, is always 0. Why is this?

...................................................................................................................................

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PI

(ii) Using the value for V, which you gave in your answer to (a)(i), determine the maximum ammeter reading.

maximum ammeter reading = ......................................

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3

Two pieces of window glass are arranged so as to form an air gap between their flat surfaces, as shown in Fig. 3.1.

f

Use

back

clip

Fig. 3.1 The pieces of glass are of the same size and their sides measure 150 mm x 150mm. The air gap is produced by a straight piece of thin wire. This keeps the two pieces of glass apart by separating the two edges on the right-hand side, as shown in Fig. 3.1 and Fig. 3.2. The two opposite edges, on the left-hand side, are held together by a strong clip. The cross-section of the air gap is a narrow triangle, as shown in Fig. 3.2.

,

air gap

I glass

wire

10.70mm

- -

I

I

60

0

I

I

150mm

75

positions along the side of the glass

Fig. 3.2 (a) The diameter of the wire is 0.70mm. By making suitable calculations, complete the table below to give the thickness of the air gap at the positions marked on Fig. 3.2. Show your working.

position / mm

0

thickness of the air gap/mm

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60

75

150 0.70

7

(b) A piece of 2mm graph paper is attached to the back surface of one piece of the glass

For Examiner 3’ Use

shown in Fig. 3.1. The apparatus, in the position shown in Fig. 3.1, is then arranged so that the bottom edge just touches some water. It is observed that the water rises up in

, wire

Pm Fig. 3.3 (i)

Describe how the height that the water rises depends upon the thickness of the air gap. Your answer should refer to the rise of the water and the thickness of the gap at the points labelled X, Y and Z on Fig. 3.3.

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............................................................................................................................... [31 (ii) How do you know that Fig. 3.3 is not a full-scale diagram?

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(iii) The water has risen in between the glass surfaces. There is another example in Fig. 3.3 where water has risen. On Fig. 3.3, label with the letter R one place where [I1 this occurs. 505414 W99 [Turn over

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Examiner's

Some textbooks claim that, in the same interval of time, black surfaces emit more radiation than white surfaces. To test this claim, the Physics class is performing the following experiment. Two small cans, having similar dimensions, are thoroughly cleaned. One is painted black and the second one is painted white. The surface of each can is dull (not shiny). The cans are filled with hot water and allowed to cool. Both cans are shielded from any draught. During the cooling, temperature-time observations are taken. The apparatus is shown in Fig. 4.1.

recording room temperature

white

black Fig. 4.1

In the space below, draw a table in which you could record all the observations would take.

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Why is it necessary to shield both cans from any draught?

................................................................................................................................... ................................................................................................................................... In addition to temperature-time observations, the temperature of the room is taken at regular intervals. Why is this necessary?

................................................................................................................................... How would you avoid making parallax errors when reading the thermometers? You may draw a diagram if you wish.

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The series circuit shown in Fig. 5.1 contains a d.c. power supply of potential difference = 4.0 V, a 0-1 A ammeter, a limiting resistor of resistance = 5.0 R , a length of resistance wire, the length 1 of which may power supply4.0v _____o 0 +

changed using a jockey.

limiting resistor 5.052 ammeter

Fig. 5.1 The circuit is used to discover how the current Z in the circuit varies with the length 1 of resistance wire used. The jockey is placed on the resistance wire at point C such that the length of wire used is I . The value of 1 is recorded as well as the corresponding value for I. The experiment is repeated for different values of I. The values are shown in the table.

Zl A

0.72

0.53

0.37

0.28

0.21

0.16

I f cm

0

10

26

40

50

70

(a) Using the grid on page 1 1 , plot the graph of I t A (y-axis) against 1 tcm (x-axis). The graph line is a curve. Draw this line. [51 (b) When 1 = 0, Z = 0.72A. What is the resistance in the circuit for this value of current?

R = V t I = ......................................

(c) Explain why Z is not inversely proportional to 1.

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