# Physics Paper 3 Questions and Answers - Asumbi Girls Pre Mock Examinations 2023

INSTRUCTIONS TO CANDIDATES

1. This paper consists of two questions 1 and 2.
2. Answer all questions in the spaces provided.
3. Non-programmable calculators and mathematical tables may be used.
 QUESTION 1 a(ii) a(iii) a(iv) a(v) a(vi) b(vii) TOTAL Maximum score 6 5 3 1 2 3 Candidates score
 QUESTION 2 a(i) a(ii) a(iii) b(vii) b(viii) b(ix) b(xi) b(xii) b(xii)I b(xii)II b(xiii) Maximum score 1 1 1 6 2 1 1 1 1 2 3 Candidates score

## QUESTIONS

Question 1
You are provided with the following:

• Two dry cell
• Cell holder
• A piece of resistance wire labeled W
• Voltmeter (0 - 3V or 0 - 5V)
• Ammeter (0 - 1A)
• A nichrome wire mounted on a millimeter scale labelled PQ
• Seven connecting wires in which four are with crocodile clips on both ends and three are with crocodile clips on one end
• Jockey attached to a connecting wire
• Micrometer screw gauge (can be shared)

Proceed as follows:

1.
1. Set up the circuit as shown in the figure below.
2. With the Jockey at Q i.e. L= 0.0 cm, take the voltmeter reading and ammeter reading. Record V and I. Repeat to get the readings for L=20.0cm, 40.0cm, 60.0cm, 60.0cm, 80.0cm and 100.0cm respectively and complete the table below.
 Length L (cm) 0.0 20.0 40.0 60.0 80.0 100.0 Voltage V (v) Current I (A)
(6marks)
3. Plot a graph of voltmeter readings (y-axis) against ammeter readings. (5marks)
4. Determine the slope of the graph (3marks)
5. What physical quantity is represented by the slope of the graph at any given point (1mark)
6. Using a micrometer screw gauge, measure the diameter, d of the wire W.
d = ..............................................mm (1mark)
= ..............................................m (1mark)
7. Calculate the quantity P = sd2π  and give its units. (3marks)
0.8

Question 2
PART A

You are provided with the following apparatus

• A meter rule
• A concave lens with holder
• A candle stick
• A white screen
• A stop watch
• Marble
• Watch glass
• Plasticine
• Micrometer screw gauge

Proceed as follows:

1. Find the approximate focal length by focusing a sharp image of a distant object onto a screen. The object (preferably window frame) must be at least 4m away. Turn lens such that side A faces the screen

1. f1=…………………………… (1mark)
2. f2=…………………….. (1mark)
3. Find the Average of f1 and f2 (1mark)
2.
1. Now Set up the apparatus as shown in figure below such that S=55cm.Adjust the position of the lens to obtain a sharp enlarged image of the candle flame. (Ensure that the candle flame, the lens and white screen same horizontal level)
2. Measure the distance u1 between the candle and the lens
3. Without changing the position of the candle and the screen, move the lens to obtain a sharp diminished image of the candle flame
4. Measure the distance u2 between the candle and the lens
5. Record the values of u1 and u2 in the table below.
6. Repeat the procedure in (i) above for S=45cm.
7. Complete the table (6marks)
 S(cm) U1(cm) U2(cm ) d=U1-U2 K = S2 - d2           4S 55 45
8. Determine the average value of K (2marks)
9. What does physical quantity K represent (1mark)
PART B
Procedure:
10. Arrange the apparatus as shown in the figure below:
11. Release the marble from the edge of the watch glass to freely oscillate. Measure the time taken, t, for 5 oscillations.
t = …………………… (1 mark)
12. Calculate the periodic time, T
T = ……………………… (1 mark)
1. Measure the diameter, D of the marble using the micrometer screw-gauge.
D = ……………………m (1 mark)
2. Determine the volume, V of the marble. (2 marks)
13. The period, T, of oscillation of the marble and radius, r of the marble are related by the equation:

Where g = 10 m/s2 and b is a constant of the watch glass. Determine the value of b (3 marks)

## MARKING SCHEME

Question 1
You are provided with the following:

• Two dry cell
• Cell holder
• A piece of resistance wire labeled W
• Voltmeter (0 - 3V or 0 - 5V)
• Ammeter (0 - 1A)
• A nichrome wire mounted on a millimeter scale labelled PQ
• Seven connecting wires in which four are with crocodile clips on both ends and three are with crocodile clips on one end
• Jockey attached to a connecting wire
• Micrometer screw gauge (can be shared)

Proceed as follows:

1.
1. Set up the circuit as shown in the figure below.
2. With the Jockey at Q i.e. L= 0.0 cm, take the voltmeter reading and ammeter reading. Record V and I. Repeat to get the readings for L=20.0cm, 40.0cm, 60.0cm, 60.0cm, 80.0cm and 100.0cm respectively and complete the table below.
 Length L (cm) 0 20 40 60 80 100 Current I (A) 0.46 0.26 0.18 0.14 0.12 0.1 @1/2 mk 2d.p must Voltage V (v) 1.8 1 0.7 0.55 0.45 0.4 @1/2 mk atleast 1d.p
(6marks)
3. Plot a graph of voltmeter readings (y-axis) against ammeter readings. (5marks)
4. Determine the slope of the graph (3marks)
S = 1.7 - 0.4
0.44 - 0.10
= 1.3/0.34
= 3.824 Ω
5. What physical quantity is represented by the slope of the graph at any given point (1mark)

Resistance of wire W

6. Using a micrometer screw gauge, measure the diameter, d of the wire W.
d = ...0.29 ± 0.02....mm (1mark)
= ...0.00029 ± 0.00002..m (1mark)
7. Calculate the quantity P = sd2π  and give its units. (3marks)
0.8
P = 3.824 x 0.000292 x π
0.8
= 1.263 x 10-6 Ωm

Question 2
PART A

You are provided with the following apparatus

• A meter rule
• A concave lens with holder
• A candle stick
• A white screen
• A stop watch
• Marble
• Watch glass
• Plasticine
• Micrometer screw gauge

Proceed as follows:

1. Find the approximate focal length by focusing a sharp image of a distant object onto a screen. The object (preferably window frame) must be at least 4m away. Turn lens such that side A faces the screen

1. f1=…10.00 cm… (1mark)
2. f2=…10.00 cm.. (1mark)
3. Find the Average of f1 and f2 (1mark)
• principal of averaging mk
• correct evaluation to 4s.f or exact with units cm mk mk
2.
1. Now Set up the apparatus as shown in figure below such that S=55cm.Adjust the position of the lens to obtain a sharp enlarged image of the candle flame. (Ensure that the candle flame, the lens and white screen same horizontal level)
2. Measure the distance u1 between the candle and the lens
3. Without changing the position of the candle and the screen, move the lens to obtain a sharp diminished image of the candle flame
4. Measure the distance u2 between the candle and the lens
5. Record the values of u1 and u2 in the table below.
6. Repeat the procedure in (i) above for S=45cm.
7. Complete the table (6marks)
 S(cm) U1(cm) U2(cm ) d=U1-U2 K = S2 - d2           4S 55 14.0     1mk 41.0       1mk 27.0 10.44 45 15.0     1mk 30.0     1mk 15.0 10.00
8. Determine the average value of K (2marks)
• principal of averaging 1mk
• correct evaluation to 4s.f or exact with units cm 1mk
9. What does physical quantity K represent (1mark)
• focal length
PART B
Procedure:
10. Arrange the apparatus as shown in the figure below:
11. Release the marble from the edge of the watch glass to freely oscillate. Measure the time taken, t, for 5 oscillations.
t = 4.02cm 1mk 2d.p
12. Calculate the periodic time, T
T = Correct evaluation to 4sf or exact with correct unit 1mk
1. Measure the diameter, D of the marble using the micrometer screw-gauge.
D = 0.01746 m
2. Determine the volume, V of the marble. (2 marks)

correct substitution 1mk
Correct evaluation to 4sf or exact with correct unit  m31mk

13. The period, T, of oscillation of the marble and radius, r of the marble are related by the equation:

Where g = 10 m/s2 and b is a constant of the watch glass. Determine the value of b (3 marks)

correct substitution 1mk
Correct evaluation to 4sf or exact with correct unit 2mks

## CONFIDENTIAL

INSTRUCTIONS

1. The information contained in this paper is to enable the head of school and the teacher in charge of Physics to make adequate preparation for this Physics practical examination.  NO ONE ELSE should have access to this paper or acquire knowledge of its contents.  Great care MUST be taken to ensure that the information herein does not reach the candidates either directly or indirectly.
2. The apparatus required by each candidate for the Physics Practical examination are set out on below.  It is expected that the ordinary apparatus of a Physics laboratory will be available.
3. The Physics teacher should note that it is his/her responsibility to ensure that each apparatus acquired for this examination agrees with the specifications as indicated on the list of apparatus below.
4. The question paper will not be opened in advance.
5. The Physics teacher is not expected to perform the experiments.

NB: Any use of apparatus other than the ones specified may lead to candidates being penalized.

QUESTION ONE
Every student should be provided with the following:

• Two new dry cell size D
• Cell holder for 2 cell
• A piece of resistance wire( Nichrome wire SWG 30) 20cm long labeled W
• Voltmeter (0 - 3V or 0 - 5V)
• Ammeter (0 - 1A)
• A nichrome wire(SWG 30)  mounted on a millimeter scale labelled PQ
• Seven connecting wires in which four are with crocodile clips on both ends and three are with crocodile clips on one end
• Jockey attached to a connecting wire
• Micrometer screw gauge (can be shared)

QUESTION TWO

• A meter rule
• A concave lens focal length 10cm
• A lens holder
• A candle stick
• A white screen
• A stop watch
• A marble
• A watch glass of diameter 10cm
• Some Plasticine

• ✔ To read offline at any time.
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