# Physics Paper 3 Questions and Answers - Achievers Joint Mock Exams 2023

INSTRUCTIONS:

• You are supposed to spend the first 15 minutes of the 2□(1/2) hours allowed for this paper reading the whole paper carefully before commencing your work.
• Marks are given for a clear record of the observations made, their suitability, accuracy and use.Candidates are advised to record their observations as soon as they are made.
• Candidates should answer the questions in English.

## QUESTIONS

Question 1.

You are provided with the following apparatus

• One boiling tube.
• One 100ml measuring cylinder.
• A piece of string 100cm long.
• A half metre rule.
• One retort stand.
• One boss and a clamp.
• A marble.
• Water source.
• Weighing balance

Procedure.

1. Weigh and record the mass mo of the marble.
mο =………………g (1/2 mark)
1. Clamp the boiling tube vertically with its base resting on the bench. Pour 5cm3 of water from the measuring cylinder into the boiling tube.
2. Using the half meter rule, measure the height, h, of the water column in the boiling tube and record in table 1 below.
3. Repeat the experiment with values of V = 10, 15, 20, 25, 30, 35, 40, 45 and 50cm3 and complete the table below. (5mks)
1. Plot a graph of volume V against height h of water column (5mks)
2. Determine the slope of the graph and state its units. (3mks)
3. Measure the length of the boiling tube H
H = ……………………cm (1/2 mark)
4. Wrap the cotton thread round the boiling tube ten times. Measure the length L of the thread. (Ensure that the windings are very close together)
L……………………………….m (1mk)
5. Calculate the volume Vb of the glass material of the boiling tube using the formula
Vb = H (2L2 – 5/2500) (2mks)
6. Empty the boiling tube and pour 50cm3 of water from the measuring cylinder. Measure and record the height h1 .
h1= ………………………………..cm (1/2 mark)
7. Carefully slide the marble into the boiling tube and record the new height h2
h2 = ……………………………….cm (1/2 mark)
8. From the graph determine the volume V1 and V2 corresponding to h1 and h2 hence determine the density ℓ of the material of the marble given that

(2marks)

QUESTION TWO.

1. You are provided with the following apparatus.
• convex lens
• Candle
• White screen
• Lens holder
• Meter rule.
• Procedure
1. Set up the apparatus as shown in figure below.
2. Place the lit candle at an object distance U=30cm. Move the screen towards or away from the lens until a sharp image of the candle flame is obtained on the screen.
3. Measure the distance V and record it in table 2.
4. Repeat the experiment for other values of U and record in the table.
5. Complete the table. (6 marks)
6. Determine the average value of f. (2marks)
7. Determine the power of the lens used in the experiment. (2 marks)
2. You are provided with the following apparatus
• A New dry cell
• An ammeter
• A voltmeter
• A mounted wire labeled AB
• Cell holder
• Switch
• Connecting wires
You are required to design a circuit that you will use the above apparatus to determine the resistance of the wire AB.
1. Draw the circuit diagram (2mks)
2. Connect the circuit you have drawn and record the measurement required. (2mks)
3. Showing the workings to determine the resistance of the wire. (2mks)
4. You are further provided with a meter rule and a micrometer screw gauge,
1. Measure the diameter of the wire. (1/2 mk)
2. Measure the length of the wire. ( 1/2 mk)
3. Determine the cross sectional area of the wire. (1mk)
4. Determine the resistivity of the material of the wire. (2marks)

## MARKING SCHEME

QUESTION I

1. Mass = ±5.4g

1.  Graph
• Axis ,both labelled or with correct units-1mk
• Scale, simple and uniform -1mk
• Plotting, all points correctly plotted- 2mk
• line, pass through at least 6 correctly plotted points -1mk
2. Slope = 25 – 10/6.6 – 3
= 4.1667cm2
3. H = 15.0 cm, ±0.2cm, 1d.p
4. L = 86.5cm ±1.0cm, 1d.p
5. V = 15(2 x 0.8152 – 5/2500)
= 22.42cm3,
6. h1 = 12.5cm ±0.5cm, 1d.p
7. h2 = 13.0cm ±0.5cm, 1d.p
8. V1 = 49cm3 V2 = 51cm3
5.4/51 – 49
= 2.7g/cm3

QUESTION 2

1.  use students values for the average
• Principle of averaging- 1 mark
• Correct evaluation to 4sf or exact with units-1mark
2. power of lens=1/f (m)
=1/ value in (d) above units Dioptres, D

2 (ii) (a)

b) A graph V against I is drawn
V= 3.0V
I= 0.3A

(c) R=v/I

(d) (i) Diameter = 0.28mm±0.2mm,2d.p
(ii) Length 60.0cm±2.0cm, 1d.p
(iii) calculation of area in m2

(iv) ρ=RA/L

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