# Physics P3 Questions, Answers and Confidential - Mangu High School Trial Mock Exams 2021/2022

INSTRUCTIONS TO CANDIDATES

1. Write your Name and Index Number in the spaces provided above.
2. Sign and write the date of Examination in the spaces provided above.
3. Answer all questions in the spaces provided.
4. You are supposed to spend the first 15 minutes of the 2½ hours allowed for this paper reading the whole paper carefully before commencing your work.
5. Marks will be given for clear records of observations actually made, their suitability, accuracy and the use made of them.
6. Candidates are advised to record their observations as soon as they are made.
7. All working must be clearly shown where necessary.
8. Mathematical tables and silent electronic calculators may be used.

FOR EXAMINER’S USE ONLY

 Question 1 b c d e f g h TOTAL Max. Score 3 2 6 5 1 1 2 20 Candidate’s Score
 Question 2 e f g h i j k l m TOTAL Max. Score 8 5 1 1 1 1 1 2 1 20 Candidate’s Score

GRAND TOTAL _________ ## Question

1. Question one
This question has two parts A and B. Answer both parts.
PART A
You are provided with the following:-
• A retort stand, clamp and boss.
• A spiral spring.
• A stop watch.
• Three 100g masses.
Proceed as follows:
1. Suspend a 100g mass at the end of the spring as shown in figure 1. Fig. 1
Now give the mass a small vertical displacement and release so that it performs vertical oscillations. Time ten oscillations and determine the period T. Enter your results in table 1.
2. Repeat the experiment for the other values of mass and complete the table.
Table 1
 Mass m (g) 100 200 300 Time for 10 oscillations (s) Periodic time T(s)
(3mks)
3. Given that where k is the spring constant, find the average value k for the spring. K (2mks)

PART B
You are provided with the following:-

• A 250ml glass beaker
• A Bunsen burner
• A Thermometer
• A Stop watch
• A Tripod stand and a Wire gauze
• A measuring cylinder 100ml
• Water
Set the apparatus as shown in figure 2 below. Fig. 2

(d) Measure 100cm3 of water and pour it into the beaker. Take the initial temperature of the water.
T0 = …………………………………………….0C (1mk)
Now heat the water to a temperature of 80ºC. switch off the gas tap and place a thermometer into the beaker and start the stop watch when the temperature is 65ºC. Take the temperature TºC of water ever two minutes. Record your results in the table 2 below.

Table 2

 Time, t(min) 2 4 6 8 10 12 14 Temperature (T)  0C (T - T0) Log (T - T0)

(5mks)
(e) Plot a graph of Log (T - T0) against Time (t). (5mks) (f) Find the value of P of log (T - T0) when t = 0. (1mk)
(g) Determine N, where N is the antilog of P. (1mk)
(h) Calculate the temperature of the surrounding TR using the expression N = 65–TR (2mks)

2. Question 2
Part A

You are provided with the following:-

• A lens and a lens holder.
• A candle.
• A white screen.

Proceed as follows:

1. Set the apparatus as shown below. 2. Place the white screen at a distance X = 100cm from the candle. Let the lens be at position P, adjacent to the lit candle.
3. Move the lens towards the screen until an enlarged image of the candle is formed on the screen. Measure and record the distance u1.
4. Move the lens to a second position Q where the image of the candle is sharp but diminished on the screen.
Measure and record the distance u2.
Hence determine the value of d = u2 - u1.
5. Repeat the procedure in (c) and (d) for either values of x = 95, 90, 85, 80cm. Complete table 2 shown below.
Table 2
 x (cm) 100 95 90 85 80 u1(cm) U2(cm) d = u2 - u1(cm) y = d2/x(cm) (2d.p)
(8mks)
6. On the grid provided, plot a graph of y against x. (5mks) 7. Determine the value of x = x0, when y = 0. (1mk)
x0 = …………………………………………… cm
8. Given that k = xo, determine the value of k. (1mk)
4

PART B
You are provided with the following:-

• A voltmeter
•  A resistance wire labelled R mounted on a metre rule.
•  A metre rule.
•  A resistance wire labelled T mounted on a small piece of carton.
• Two dry cells and a cell holder.
• Six connecting wires, each with a crocodile clip at one end.
•  A switch.

Proceed as follows;

i). Measure and record the e.m.f. E0 of the cells connected in series, E0 = ____ v.(1mk)
j). Connect the circuit as shown below. Point O on resistance wire P is at 50cm mark of the metre rule. A and B are points on resistance wire P such that AO = OB = X = 30cm. (k) Close the switch. Read and record the potential difference V across AO
V = …………………………………………. Volts. (1mk)
(l) The relationship between V and x is given by:
I = 35 + 1
V   x      y
Determine the value of y. (2mks)
(m) Use the e.m.f. E0 to determine the constant k, given that:
k    =    8     (1mk)
35E0 ## MARKING SCHEME

Question one

1.
Table 1
 Mass m (g) 100 200 300 Time for 10 oscillations (s) 4.75 6.74 8.02 Periodic time T(s) 0.475 0.674 0.0802
(3mks)
Award 2 marks 3 correct values for 10 oscillations to 2d.c
1 mark for two correct values
Award 1 mk for correct evaluation of T
2.
3. T = π√(m)
k
{K1 = 4.375, k2 = 4.346, k3 = 4.605} award 1 mk
K = 4.442 kg/m  or  44.42 N/m  award 1 mk
4. To = 23.0ºC (1 mark)

Table 2

 Time, t(min) 2 4 6 8 10 12 14 Temperature (T)  0C 61 57 53 51 49 47 45 (T - T0) 38 34 30 28 26 24 22 Log (T - T0) 1.58 1.531 1.477 1.477 1.415 1.38 1.342

(5mks)
award half a mark for correct value of T up to max. of 6 positions
award 1 mk for correct evaluation of (T-To)
award 1 mk for correct evaluation of log(T-To)

5. on the grid paper
plotting P = 2 marks
scales S = 1 mk
labelling axes A = 1 mk
line L = 1 makr with -ve gradient
6. P = y-intercept
=1.61 1 mk
evidence from the graph
7. N = the antilog of P
=antilog of 1.61
=40.74*c 1 mk
8. N = 65 - TR
40.74 = 65 - TR
T= 24.26ºC
9. 2.

Table 2

 x(cm) 100 95 90 85 80 u1(cm) 25 27 29 30 32 +1.0cm u2(cm) 71 64 61 52 48 +1.0cm d=u2-u1(cm) 46 37 32 22 16 y = d2 (cm)      x (2dp) 21.16 14.41 11.38 5.69 3.2 (8mks)

(8mks)
u1 and u2 values each ½ mk
d value a maximum of 1 mark 4 – 5 = 1mk
3 values = ½ mark
y value a maximum of 2 marks correct to 2d.p
4 – 5 = 2 marks
3 = 1 mark
(f) Axes with units = 1 mark (each axis = ½ mark)
Simple and uniform scale = 1 mark (vertical axis only)
Plotting within 1 small square = 2 marks (4 – 5 = 2 marks)
(3 = 1 mark)
Straight line drawn with a ruler = 1mark
(Line should have positive gradient and passes at least 3 plotted points)
(g) Xo = 80cm ± 1cm
(h) k = Xo = 80 = 20cm ± 0.5cm
4       4
(i) Bo = 3.0v ± 0.1v
(k) v = 0.40 volts ± 0.05v
(l) 1 = 35 + 1
v      x     y
=   1    = 35 + 1
0.40     30    y
y = 0.75v
(m) k =    8    =     8     = 0.07619 or 0.0762 v-1
35Eo      35x3
A GRAPH OF y(cm) AGAINST x(cm)  ## CONFIDENTIAL

QUESTION 1
Each candidate should have:-

• A retort stand, clamp and boss
• A spiral spring
• A stop watch
• Three 100g masses
• A 250ml glass beaker
• A Bunsen burner
• A thermometer (-10 to 110ºC)
• A tripod stand and wire gauze
• A measuring cylinder 100mll
• A source of heat
• Some water in a container about 500ml

QUESTION 2
Each candidate is required to have the following apparatus:

• A voltmeter (0 – 5V)
• A candle
• A white screen
• Two new dry cells
• Six connecting wires, each with a crocodile clip at one end.
• A switch.
• A lens and a lens holder. NB: Focal length = 20cm.
• A metre rule.
• A resistance wire labelled R mounted on a metre rule.
The physics teacher is required to mount a nichrome wire SWG 28 on a metre rule and label the wire R. The diameter of the wire is 0.36mm.
• A resistance wire labelled T.
The Physics teacher is required to mount a nichrome wire SWG 28 on a small piece of carbon box and label it T.
The diameter of the wire is 0.36mm and its length is 60cm. • ✔ To read offline at any time.
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