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KAKAMEGA CENTRAL DISTRICT PHYSICS PRACTICAL QUESTIONS
Question 1
You are provided with the following apparatus;
- A wooden plank of length 1m or a meter rule
- A meter rule
- A half- meter (can be shared)
- Two complete retort stands
- Some thread
- A stop watch/ clock
Proceed as follows:-
1 a) Set up the apparatus as shown. Ensure the loops on the wooden plank and meter rule are
loose to enable easy sliding of the threads.
The separation between the meter rule and the plank must remain 20cm throughout
the experiment.
b) i) Adjust the positions of the thread such that one is at the 10cm mark and the other at the 90cm
mark so that the distance marked d is 80cm. Maintain the threads vertical
by moving the
loops on the plank.
ii) Now displace one end of the meter rule slightly on a horizontal plane so that when released
it oscillates about a vertical axis as in the figure below.
iii) Measure the timer for 10 oscillations and record the value in the table provided below
c) i) Repeat the procedure in (b) above for the values of d shown in the table (set the values of
d by adjusting the positions of the loops in steps of 5cm on both sides)
ii) Complete the table
D (cm) | D (m) | 1/d2 (M-2) | Time for 10 oscillations | Period T (s) | T2 (S2) |
80 | |||||
70 | |||||
60 | |||||
50 | |||||
40 | |||||
30 | |||||
20 |
d) i) On the grid provided, plot a graph of T2 (y – axis) against 1/d2 (M-2) ii) Determine the slope of your graph
iii) Given that T2 = 16K2
where K is a constant. Use the graph to determine the value of K
5d2
QUESTION 2
This question has two parts A and B. Answer both parts.
You are provided with the following:
- A lens and a lens holder
- A candle
- Object consisting of a hole 2cm in diameter and parallel wires 1.5cm apart in a stiff card. (See diagram below)
- A screen
- A meter rule
Proceed as follows:-
a) Illuminate the object with the candle flame.
b) Arrange the object, lens and screen in line as shown in figure 3 below
c) Measure the distance, d, between the two parallel wire that acts as the object
d = ………………… cm
d) Adjust the lens, u to 80cm
e) Move the screen until a clear image is formed on it.
f) Measure the distance, X, of the image, making sure that what you measure is an image corresponding
to the previous reading, d.
Record these values in the table below:-
g) Repeat your readings of x with u = 70, 60, 50, 40 and 30cm and complete the table
U (cm) | 80 | 70 | 60 | 50 | 40 | 30 |
X(cm) | ||||||
d/ x |
h) i) On the grid provided plot a graph of u (y – axis) against d/x
ii) I . Determine the slope, S of the graph
II. Find the intercept on the u – axis
PART B
You are provided with the following:-
- A jockey J
- An ammeter
- A voltmeter
- A switch
- 6 connecting wires, Z with crocodile clips on one end
- A resistor wire labeled XY mounted on a piece of wood having a millimeter scale
- 2 new dry cells
Proceed as follow:
I) i) Connect the circuit as shown below:
ii) Close the switch and note the voltmeter and ammeter readings when XJ = 10cm
iii) Repeat procedure (i) and (ii) above with XJ = 20 cm and enter in the table 3 as below: *KKC*
Table 3:-
Length XJ (cm) | P.d.V . (v) | Current, I (A) |
10 | ||
20 |
J) Given that log I = n log V + log k, where k and n are constants, determine the values of k and n
KAKAMEGA CENTRAL DISTRICT PHYSICS PRACTICAL ANSWERS
1. c)i) Repeat the procedure in (b) above for the values of d shown in the table (set the values of d by
adjusting the positions of the loops in steps of 5cm on both sides)
ii) Complete the table
D (cm) | D (m) | 1 (M-2) d2 | Time for 10 oscillations
| Period T (s) | T2 (S2) |
80 | 0.80 | 1.5625 | 5.91 | 0.591 | 0.3493 |
70 | 0.70 | 2.04082 | 7.66 | 0.766 | 0.5868 |
60 | 0.60 | 2.778 | 8.65 | 0.865 | 0.7482 |
50 | 0.50 | 4.000 | 10.44 | 1.044 | 1.0899 |
40 | 0.40 | 6.2500 | 12.88 | 1.288 | 1.6589 |
30 | 0.30 | 11.1111 | 16.94 | 1.694 | 2.8696 |
20 | 0.20 | 25.000 | 25.41 | 2.541 | 6.4567 |
d ) i) On the grid provided, plot a graph of T2 (y – axis) against 1/d2 (M-2)
ii) Determine the slope of your graph
Slope = (250 -0) X 10
-2 S2 S = 2.5 X 10 -1 M2 S2
(100 -0) X 10 -1 M -2 S= 0.25 M2S2
iii) Given that T2 = 16K2 where K is a constant. Use the graph to determine the value of
5d2
16K2 = slope K =
0.25 X 5 M2S2
5 16
K2 = S X5 K = 0.2795
16
QUESTION 2
c) Measure the distance, d, between the two parallel wire that acts as the object d =1.50 cm
Record this value in the table below.
g) Repeat your readings of x with u = 70, 60, 50, 40 and 30cm and complete the table (5 marks)
U (cm) | 80 | 70 | 60 | 50 | 40 | 30 |
X(cm) | 0.5 | 0.7 | 0.9 | 1.2 | 1.8 | 3.2 |
d/ x | 3 | 2.143 | 1.667 | 1.250 | 0.833 | 0.469 |
i) On the grid provided plot a graph of u (y – axis) against d/x
ii) I . Determine the slope, S of the graph
S = 85 -40 S = 45
275 -80 X 10-2 195 X10-2
= 23.076 cm
II. Find the intercept on the u – axis
U – intercept = 20.0 cm
PART B
iii) Repeat procedure (i) and (ii) above with XJ = 20 cm and enter in the table 3as below
Table 3
Length XJ (cm) | P.d.V . (v) | Current, I (A) |
10 | 1.1 | 0.45 |
20 | 1.5 | 0.25 |
J) Given that log I = n log V + log K, where k and n are constants, determine the values of k and n
log(0.45) = n log (1.1) + logk -0.03468 = 0.0414n
log(0.25) = n log (1.5) + logk -0.6021 = 0.1761n
0.2553 = -0.13469n
n= 1.8955
T. 6532 0.414 n = 0.2553
– T.3979 = 0.1761 n -0.1347
0.2553 T.8653 n = -1.8955
log(0.45) = -1.8955 log(1.1) + log k
log k = log (0.45) + 1.8955 log (1.1)
= T .6532 + 1.8955X0.0414
= T.6532
+ 0.0785 log = T.7317
T .7317
K = 0.53913.