Question

The values of current (I) flowing through a given resistor of resistance (R), for the corresponding values of potential difference (V) across the resistor are as given below:
V (volts)
0.5
1.0
1.5
2.0
2.5
3.0
4.0
5.0
I (amperes)
0.1
0.2
0.3
0.4
0.5
0.6
0.8
1.0
Plot a graph between current (I) and potential difference (V) and determine the resistance (R) of the resistor.

Answer 1

The graph for current (I) and potential difference (V) is given in the image below.

The slope of the line gives the resistance:

Resistance (R) = Slope of line (m)

$\bold{m=\frac{1-0.5}{0.2-0.1}}$

$\bold{m=\frac{0.5}{0.1}=5 \ \Omega}$

So, the resistance is 5 ohms.

The resistance is given by the formula:

$\bold{R=\frac{V}{I}}$

When the V = 0.5 volts and I = 0.1 A, we get,

$\bold{R=\frac{0.5}{0.1}=5 \ \Omega}$

When the V = 4.0 volts and I = 0.8 A, we get,

$\bold{R=\frac{4.0}{0.8}=5 \ \Omega}$

The slope line is a straight line in the graph.

Thus, the circuit obeys ohms law and the maintained resistance is 5 ohms.