Experiment 3
In this experiment you will determine the ratio of internal resistance of a dry cell to the resistance
per meter of the wire provided
Apparatus:
1dry cell, Voltmeter (0-3V), Constantine wire SWG 28, Q, 5 pieces of connecting wires, 1
switch, 1 meter ruler, cell holder, 2 pieces of cello tape and a cell holder.
Procedure
(a) Connect the dry cell, the switch, K, and a voltmeter, V, across a length L of a Constantine
wire as shown in figure 3 below.
Switch K
V
Crocodile clip
L
Fig. 3
(b) Starting with L = 0.200m, close switch, K. Read and record the value of V on the
voltimeter.
(c) Repeat procedures (b) for values of L = 0.300, 0.400, 0.500, 0.600, 0.700 and 0.800m.
(d) Tabulate your results including values of
1
1
(e) Plot a graph of 𝑉 against 𝐿
1
(f) Determine intercept C on the 𝑉 axis.
1
𝑉
1
and 𝐿
(g) Determine slope S of your graph
(h) Find the value of
100𝐶
𝑆