The diagram illustrates an electrical circuit used to investigate a science experiment. The rheostat is adjusted to vary the current and voltage in the circuit. Fig 2 (a) and Fig 2 (b) below illustrate ammeter readings I=I1, I2, I3, I4, I5 and voltmeter readings v=v1, v2, v3, v4, and v5, in table 1 below respectively when the key is closed.

Step 1: Read and record the ammeter readings from Fig. 2(a).

The meter scales show the following values for the needle positions:

Step 2: Read and record the voltmeter readings from Fig. 2(b).

The meter scales show the following values for the needle positions (in volts):

Step 3: Verify Ohm's law using $V = IR$.

For low setting:
$R = \frac{V_L}{I_L} = \frac{1.0}{0.20} = 5.0~\Omega$

For medium setting:
$R = \frac{V_M}{I_M} = \frac{2.0}{0.40} = 5.0~\Omega$

For high setting:
$R = \frac{V_R}{I_R} = \frac{3.0}{0.60} = 5.0~\Omega$

Average resistance $R = 5.0~\Omega$.

Step 4: Plot the graph with $I$ (vertical axis, in A) vs $V$ (horizontal axis, in V).

Plot the points: $(1.0, 0.20)$, $(2.0, 0.40)$, $(3.0, 0.60)$.

The graph is a straight line through origin with slope $\frac{1}{R} = 0.20~\mathrm{A/V}$.

R = 5.0 \Omega