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Ocep college

Mock examination 2015

Physics 9702

Paper 3

Time : 2 hours

Read these instructions first

Write your name on all the work you hand in.

Write in dark blue or black pen.

You may use pencil for any diagrams or graphs

Do not use staples, paper clips, highlighters, glue or correction fluid.

Attempt all questions

The total marks for this paper is 40.

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1 In this experiment, you will investigate how the current in a circuit varies as the resistance

of the circuit is changed.

(a) Measure and record the length L of wire between the crocodile clips on the wire labelled F.

(b) Set up the circuit as shown in Fig. 1.1.

+

A crocodile clip

metre rule

wire crocodile clip

Fig. 1.1

(c) (i) Attach wire F to the wire on the metre rule as shown in Fig. 1.2.

+

A x

F

Fig. 1.2 The distance x between the crocodile clips should be approximately 50 cm.

(ii) Measure and record x.

(d) (i) Close the switch.

(ii) Record the ammeter reading I. (iii) Open the switch.

(e) Change x and repeat (c)(ii) and (d) until you have six sets of readings of x and I.

Include values of 2

(+) and

1

in your table.

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(f)

(i) Plot a graph of 1

on the y-axis and

2

(+) on the x-axis.

(ii) Draw the straight line of best fit.

(iii) Determine the gradient and y-intercept of this line.

(g) The quantities I, x and L are related by the equation

1

=

2

( + )+

where P and Q are constants

Using your answers in (f)(iii), determine values for P and Q. Give appropriate units.

2) In this experiment you will investigate the height to which a ball rises when it has been

released from a stretched piece of rubber.

a. (i) Suspend the piece of rubber from a clamp and stand using the two small

blocks of wood. Attach the ball to the lower end of the rubber. The arrangement

should be as shown in Fig. 2.1.

blocks of wood

piece of rubber

ball

Fig. 2.1

(ii) Clamp the rule vertically. Position the rule near to the suspended ball.

(iii) Record the position of the centre of mass of the ball when it is in equilibrium.

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b) (i) Pull the ball vertically downwards. Record the new position of the centre of mass of

the ball and determine its vertical displacement x.

(ii) Release the ball and note the position of its centre of mass when the ball reaches

maximum height. (iii) Calculate the maximum height h of the ball above the equilibrium position.

c) Estimate the percentage uncertainty in h, showing your working.

d) Change the value of x and repeat (b). Record the new values of x and h.

e) It is suggested that h is directly proportional to 2. Do the results of your experiment support this idea? You should explain your reasoning clearly.

f) (i) State four sources of error or limitations of the procedure in this experiment.

(ii) Suggest four improvements that could be made to this experiment. You may suggest

the use of other apparatus or different procedures.