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Physics · Paper 2B · 2020

2 questions

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Questions (2)

Section A

1. 25 marks

You are provided with a retort stand with its accessories, two pieces of wood, a thread, pendulum bob, stop watch and a meter rule. (a) Hang the pendulum bob on one end of a 90 cm length of thread and clamp the other end firmly between two small pieces of wood as shown in Figure 1. (b) Displace a pendulum bob to a small distance and release it such that, It begins to swing to and fro motion. Determine the time t for twenty (20) complete oscillations and hence the corresponding periodic time, T. (c) Repeat the procedures in 1 (b) for the values of L=70 cm, 50 cm, 30 cm and 10 cm.

Diagram for question 1
(i) Construct a table of results that includes the values of T 1 mk
(ii) Plot a graph of L (cm) against $T^2$ (sec$^2$) 1 mk
(iii) From the graph determine the slope G 1 mk
(iv) Find the value of the acceleration due to gravity, g. 1 mk
((c)(i) Find the value of the acceleration due to gravity, g. 4 mk
((c)(v) Give two importance of the value obtained in 1(iv) in daily life activities. 4 mk
(v) Give two importance of the value obtained in 1(iv) in daily life activities. 1 mk

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Section B

2. 25 marks

You are provided with a resistance box R, a dry cell E, a switch S, a jockey J and a centre- zero galvanometer. Determine the value of the unknown resistance X by means of a metre bridge as follows: (a) Set up the circuit as shown in Figure 2. (b) Set R =1Ω, close the switch, slide the jockey over the metre bridge wire until the galvanometer reads zero. Read and record the length $L_1$. Also read and record the corresponding length $L_2$. (c) Repeat the procedures in 2 (b) for values of R = 2Ω, 3Ω, 5Ω and 7Ω and record the values for $L_1$ and $L_2$ in each case.

Diagram for question 2
(i) Tabulate your results including the values of $\frac{L}{L}$ 1 2 1 mk
(ii) Plot a graph of R against $\frac{L}{L}$ 1 2 1 mk
(iii) Find the slope S of the graph 1 mk
(iv) Determine the value of the unknown resistance X by showing clearly how you arrive at your answer. 1 mk
((c)(i) Determine the value of the unknown resistance X by showing clearly how you arrive at your answer. 8 mk

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