KNEC KCSE Physics Paper 3 Question Paper / 2016 KCSE 4MCK Joint Exam

Q1. PART A
You are provided with the following
• A voltmeter
• An Ammeter
• Six connecting wires
• A cell holder
• A torch bulb
• Two new dry cells
• A switch
Proceed as follows
a) i) Connect the apparatus provided as shown in figure below.

ii) Close the switch and record the ammeter and voltmeter readings.
I = _____________________________________________________ (1mark)
V = _____________________________________________________ (1 mark)
iii) Using the relation KI = V, calculate K for the bulb stating its units. (2 marks)

PART B
You are provided with the following
• Two dry cells
• A voltmeter
• An ammeter
• A wire mounted on a mm scale (1m long)
• A switch
a)i) Connect the circuit as shown in figure below

N.B- The switch should be open when no readings are being taken.
ii) Adjust the length of the nichrome wire PQ to PC = 75cm, using the crocodile clip at C. Close
the switch and record the voltmeter and ammeter readings in table below.
iii) Repeat (a)(ii) for length PC equal to 65cm,55cm,45cm,35cm, and 25cm. (4 marks)

b)i) On the grid provided, plot a graph of I against V. (5 marks)

ii) Determine the slope of your graph. (3 marks)

iii) If the equation relating I and V is

Use your graph to determine the value of
R = ________________________________________________ (2 marks)
P = ________________________________________________ (2 marks)

Q2. PART A
You are provided with the following
• A rectangular glass block
• Four optical pins
• A soft board
• A plane paper A4
Proceed as follows
a) Place the glass block on the plane paper with one of the largest faces upper most. Trace
round the glass block using a sharp pencil as shown below

b) Remove the glass block and construct a normal at B. Construct an incident ray AB of
angle of incident equal to 20°.
c) Replace the glass block and trace the ray ABCD using optical pin P3 and P4.
d) Remove the glass block and draw the path of ray ABDC using a pencil, measure the
length L = BC and record its value in the table below.
e) Repeat the procedure above for the angles of incident given in the table below and fill the
rest of the table as required.
(6 marks)
f) Plot a graph of sin²(i) (y-axis) against 1/L₂ (5 marks)

g) Calculate the gradient, m, of the graph (3 marks)
h) i) Measure the width, b, of the glass
b = ____________________________________ (1 mark)
ii) Calculate the value of 𝑀𝑀
𝑏𝑏 (1 mark)
PART B
a) You are provided with the following:
• Meter rule
• White screen
• A candle
• Lens and lens holder
Proceed as follows
i) Set up the experiment as shown

ii) Starting with L₁ = 30cm, adjust the position of the candle in order to obtain a sharp image or
screen and record the value of L₂‍
L₂ = _____________cm (1 mark)
iii) Repeat the procedure for L₁ = 60cm
iv) Fill and complete for the values of 𝐿𝐿L₁/L₂ below (2 marks)

v) Given that , where m – magnification, determine the value of focal length, F.
(2marks)