## MUMIAS DISTRICT PHYSICS PRACTICAL QUESTIONS

1.  You are provided with the following apparatus:

• Ammeter (0-2.5A)
• A voltmeter (0 –5 V)
• A straight wire AB 1.0m long mounted on a millimeter scale
• Two jockeys
• Connecting wires
• Micrometer screw gauge (to be shared)
• Two dry cells (size D) a cell holder and a switch
• A cell holder
• Switch

Procedure:

(a) Using the micrometer screw gauge, determine the diameter d of the wire

Set up the apparatus as shown in fig. 1

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Fig. 1

With both jockeys set at L=10cm from A, measure the current I through the wire and voltage (V) across. Repeat these corresponding values of current I and voltage (V) in the table below:

 Length (cm) 10 20 30 40 50 60 70 80 90 100 Length (m) Current I(A) Voltage V(V) R = V/I ()

(i) Using the values in table I plot a graph of Resistance R() against length L(m)

(i) Determine the slope of the graph

(ii) Determine the resistivity of the material of the wire given that;

R = 4ρh

d2

2. You are provided with the following apparatus:

• A spring balance, (0-2.5N)
• A retort stand, a boss and a clamp
• A wooden block
• One 50g mass
• A beaker and some water
• Five pieces of strings
• A vernier calipers (to be shared)

Procedure

(a) Measure the length of the wooden block using a vernier calipers L =

(b) From the lower end of the wooden block, mark levels on the wood at intervals of 1cm for 5cm   as shown. Mark these levels using pieces of thread

(c) Set-up apparatus as shown below in fig 2.

Fig. 2

(d) Lower the mass into the empty beaker provided. The mass should be as low as possible by not

touching the base of the beaker.

Record the reading W1 of the spring balance

(i) Slowly pour water into the beaker until the mass is completely immersed. Continue adding

Water into the beaker until when the level reaches mark (thread) indicating 1cm on the wooden  block. Read and record the value W2
of the spring balance (Don’t disturb the wood and mass  when pouring water into the beaker)

(e) Repeat procedures in d(ii) above by adding water up to the line indicating 2cm, 3cm,

4cm and 5cm. Denote these lines by values h. Complete the table for different values of h

 h(cm) 1 2 3 4 5 W2 (N) F= (W1 – W2) (N)

f. (i) Plot a graph of F against h

(ii) Determine the gradient of the graph

(iii) Given that F =Dgh + C Whereby D and C are constants, g = 10N/kg

100

use the graph to determine the values of D and C   d

(iv) Determine the constant W for the wooden block given that W = DL

## MUMIAS DISTRICT PHYSICS PRACTICAL ANSWERS

1. diameter d = 0.28mm + 0.02

 Length (cm) 10 20 30 40 50 60 70 80 90 100 Length (m) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.1 Current I (A) 0.7 0.54 0.44 0.32 0.28 0.26 0.22 0.2 0.18 0.16 Voltage V (V) 1.2 1.8 1.8 2.2 2.4 2.5 2.5 2.6 2.7 2.74 R= v/I (x) 1.71 3.33 4.09 6.88 8.57 9.62 11.36 11.36 13 17.13

b) GRAPH

i) Axes- labeled with correct units

Scale – simple, uniform, and consistent and accommodate all values

Points – 4 correctly plotted points within an error of one small square

Line- straight line passing through at least 3 correctly plotted points

ii) Gradient = R/L = 16.4 – 0/1.04 = 15.7692nm-1

iii) R = 4p2/d2

M= 4p/d2

P = md2/4

= 15.7692 X (0.28 X 10-4)2

4  = 9.7265 X 10-8 RM

2.  a) L = 8.0 cm

1. i) 0.80 + 0.2
 H(cm) 1 2 3 4 5 W2(N) 0.8 0.7 0.6 0.5 0.4 F = (W1 – W2)N 0.2 0.3 0.4 0.5 0.6

f) i) Labelling

Appropriate scale

Plotting

Straight/ smooth line

ii) M = DF/DH

= 0.6 – 0.2/5-1

= 0.4/4

= 0.1/cm

iii) Dg/100 = m

D X 10/100 = 0.1/0.01

= 100Kg/m

iv) W= 100Kg/m X 0.075m  = 7.5 Kg

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