Question

A 10 m long wire of resistance $20O$ is connected in series with a battery ofemf3V and a resistance of $10O$ The potential gradient along the wire in V /m is

• A. 0.02
• B. 0.1
• C. 0.2
• D. 1.2

Answer 1

Answer: (C)

0.2

Answer 2

As resistances are in series $R_{total} = R_1 + R_2$ $= 20 + 10 = 30 O$ $i = \frac{4}{R_{total}} = \frac{3}{30} = \frac{1}{10} A$ So, $V_{wire} = i R_{wire}$ $\Rightarrow V_{wire} = \frac{1}{10} \times 20 = 2V$ Hence, potential gradient is $\frac{V_{wire}}{l} = \frac{2}{10} = 0.2 V/m$