Paper 3 May 2001 Physics

UNIVERSITY OF CAMBRIDGE LOCAL EXAMINATIONS SYNDICATE General Certificate of Education Ordinary Level

PHYSICS PAPER 3 Practical Test MAY/JUNE SESSION 2001

5054/3 2 hours

Candidates answer on the enclosed answer booklet. Additional materials: As listed in Instructions to Supervisors Electronic calculator and/or Mathematical tables Graph paper

TIME

2 hours

INSTRUCTIONS TO CANDIDATES Write your name, Centre number and candidate number in the spaces provided on the answer booklet. Answer all questions. Write your answers in the spaces provided in the answer booklet. For each of the questions in Section A, you will be allowed to work with the apparatus for a maximum of 20 minutes. For the question in Section B, you will be allowed to work with the apparatus for a maximum of 1 hour. You are expected to record all your observations as soon as these observations are made. All of your answers should be written in the answer booklet; scrap paper should not be used. An account of the method of carrying out the experiments is not required. At the end of the examination, hand in only the answer booklet. INFORMATION FOR CANDIDATES Graph paper is provided in the enclosed answer booklet. Additional sheets of graph paper should be used only if it is necessary to do so. Any additional sheets should be attached firmly to the answer booklet.

This question paper consists of 5 printed pages, 3 blank pages and an inserted answer booklet. ND/PW QF10454/2 © UCLES 2001

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2 Section A Answer all the questions in this section. 1

In this experiment, you will determine the density of the solution. Record your answers on page 2 of your answer booklet. You are to use the apparatus provided to determine the density of the solution which is provided in the beaker. You do not have to use the whole sample. You will use the relationship density =

mass . volume

(a) In your answer booklet you should describe carefully the method used to find both the mass and the volume of the part of the solution which you used. You may include diagrams if you wish. (b)

(i) Record all your measurements. (ii) Calculate the density of the solution.

(c) Return the solution to the beaker after completing your measurements.

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3 2

In this experiment, you will determine the focal length of a lens by observing two images formed by the lens. Record your answers on page 3 of your answer booklet. (a) Set up the apparatus as shown in Fig. 2.1 with the object 20 cm from the lens. Adjust the position of the screen until a clearly focused image of the cross-wire object is formed on the screen. Ensure that the light source is in line with the cross-wire object so that the image formed on the screen is as bright as possible.

Fig. 2.1 (b) Describe fully the image which is formed on the screen. (c) Measure and record the distance D between the object and the screen. (d) Without adjusting the position of the screen or the object, move the lens until a second clear image is formed on the screen. (e) Describe fully the image which is formed on the screen in this case. (f)

Measure and record the distance d through which the lens was moved.

(g) Calculate the focal length f of the lens given that f=

D2 – d2 . 4D

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4 3

In this experiment, you will determine the period of oscillation of a system when masses of 200 g and 400 g are suspended from a spring. Record your answers on page 4 of your answer booklet. (a) Suspend the spring from the clamp as shown in Fig. 3.1.

Fig. 3.1

Fig. 3.2

(b) Suspend a mass m1 of 200 g from the end of the spring. (c) Clamp the optics pin in the cork horizontally, level with the base of the mass and to its side as shown in Fig. 3.2. Pull the mass down approximately 2 cm and release it. The mass will perform vertical oscillations. One complete oscillation of the mass is shown in Fig. 3.2. Take and record measurements to determine the period T1 of the oscillation of m1. (d) Replace the 200 g mass with a mass m 2 of 400 g and repeat step (c) to find the period T2 of the oscillation of m2. 2 2 (e) Calculate T1 and T2 . m2 m1

(f)

Use the results from your answer to (e) to suggest a relationship between mass and period.

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5 Section B 4

In this experiment, you will investigate how the resistance of a length of wire depends on its length. Use pages 5, 6 and 7 of your answer booklet for your answers. (a) Draw a circuit diagram of the electrical circuit which has been set up for you. (b) Close the switch and adjust the current I in the circuit to a value of approximately 0.15 A. Measure and record I. (c) Using the sliding contact, connect the voltmeter across a length l of 0.500 m of wire. Record the voltmeter reading V. (d) Calculate the resistance R of the wire of this length, given that R=

V .

I

(e) Keeping the current constant, measure and record V for a range of values of l. After completing your readings, open the switch. Tabulate your values of l, V and R. (f)

Plot a graph of R/Ω (y-axis) against l /m (x-axis).

(g) Find the gradient G of your graph. (h) Write down a conclusion about the relationship between resistance and length. State the meaning of the gradient of your graph.

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