MARANDA HIGH SCHOOL
The Kenya Certificate of Secondary Education
MOCK EXAMINATION
232/3 Physics (Practical) Paper 3
Time: 2 Hours 15 Mins
Name: ………………………………………….…….…… Adm No: ………………
Stream: ……………………….. Signature: …………….
Instructions to Candidates
- Write your name and index number in the spaces provided above.
- Sign and write the date of examination in the spaces provided
- Answer ALL the questions in the spaces provided in the question paper
- You are supposed to spend the first 15 minutes of the 2 ½ hours allowed for this paper reading the whole paper carefully before commencing your work.
- Marks are given for a clear record of the observations actually made.
- Non-programmable silent electronic calculators and KNEC Mathematical tables may be used except where stated otherwise.
FOR EXAMINERS USE ONLY
QUESTION 1
| TOTAL | |
| Maximum Score | 20 |
| Candidate’s Score |
QUESTION 2
| TOTAL | |
| Maximum score | 20 |
| Candidate’s score |
TOTAL SCORE
QUESTION 1
You are provided with the following: –
- 2 new size D dry cells in a cell holder
- A torch bulb in a bulb holder
- A switch
- An Ammeter
- Seven connecting wires at least two with crocodile clips
- A resistance wire PQ mounted on a mm scale
- A micrometer screw gauge (to be shared)
- A Voltmeter
Proceed as follows:
- Set up the circuit as shown in the figure 1 .
Figure 1
- With the crocodile clip at P, take the voltmeter reading and ammeter reading. Record V and I. Repeat the readings for L= 80, 60, 40, 20 and 0 cm respectively and complete table 1. (5 marks)
Table 1
| Length, L (cm) | 80 | 60 | 40 | 20 | 0 |
| Voltage, V (V) | |||||
| Current, I (A) |
- What changes do you observe on the bulb as L decreases from P? (1 mark)
………………………………………………………………………………………………………………………………………………………………………………………………
- Plot a graph of Ammeter reading (y-axis) against Voltmeter readings. (4 marks)
- Determine the slope of the graph at . (3 marks)
…………………………………………………………………………………………………………………………………………………………………………………………………….…………………………………………………………………………………………
- What physical quantity is represented by the slope of the graph at any given point?
(1mark)
………………………………………………………………………………………………
- Given the apparatus above, draw a diagram of the circuit you would use to determine the current through the resistant wire and the potential difference across. (2 marks)
- Set up the circuit you have drawn. Record the ammeter reading and the voltmeter reading when
V = …………………………………….…….. (mark)
I = ……………………………………….. (mark)
- Using a micrometer screw gauge, measure the diameter of the wire. (1 mark)
d = ……………………………………………m
- Calculate the quantity and give its units, where . (2 marks)
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
QUESTION 2
PART A
You are provided with the following apparatus:
- Metre rule
- Thread
- A complete retort stand
- Two masses, a 50g and 20g mass
- Water in a beaker
- Liquid X in a beaker
- Suspend the metre rule so that it balances at its centre of gravity G. Read and record the value of G.
…………………………………………………………………… (1 mark)
- Suspend the 50g mass at a distance , then suspend the 20g mass and adjust its position such that the metre rule is balanced as shown in the figure 2
Figure 2
- Record the distance distance
…………………………………………………. cm (1 mark)
- While maintaining the distance , immerse the the 50g mass completely in water, as shown in the figure 3.
Figure 3
- Adjust the position of the 20g mass to balance the metre rule again. Record the new distance
………………………………………………………….. cm (1 mark)
- Using the results obtained above, calculate the value of , weight of the 50g mass in water.
(2 marks)
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
- Determine the upthruston the 50g mass in water. (2 marks)
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
- Repeat steps (d), (e) and (f) but now the 50g is totally immersed in liquid X as shown in the figure 4.
Figure 4
- Using the results obtained above, calculate the value of , weight of the 50g mass in liquid X. (2 marks)
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….
- Determine the upthruston the 50g mass in liquid X. (2 marks)
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
- Given that where . Calculate (2 marks)
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
QUESTION 2
PART B
You are provided with the following apparatus:-
- A metre rule.
- Stop watch.
- Stand, clamp and boss.
- Two pieces of wood.
- A beam balance or electronic balance (to be shared)
- Mass labelled M.
Proceed as follows:
- Hang the spring vertically by clamping one end as shown in figure 5.
Figure 5
- Measure the length, of the unloaded spring, and record below.
= ……………………………………………… cm (1 mark)
- Hang the mass M given from the lower end of the spring. Measure the length, of the loaded spring.
= ………………………………….. cm (1 mark)
- Find the value of
= ……………………………………..cm (1 mark)
- Using the beam balance, determine the mass, M of the object.
M = …………………………………………kg (1 mark)
- Hang the mass M from the lower end of the spring. Displace it by a small vertical distance and release so that the spring makes vertical oscillations. Measure and record, time for the number of oscillations given in the table 2.
- Complete table 2. (3 marks)
| Oscillations, N | 10 |
| Time in seconds, t (s) |
|
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