Question

A 10 m long wire of resistance 20 Ω is connected in series with a battery of emf 3V (negligible internal resistance) and a resistance of 10 Ω. Find the potential gradient along the wire–

• A. 3 V/m
• B. 0.2 V/m
• C. 0.1 V/m
• D. 0.3 V/m

Answer 1

Answer: (B)

0.2 V/m

Answer 2

= (R_wire) × $\frac{I}{\mathcal{l}}$

I = $\frac{\varepsilon}{(R_{wire} + R_{external})}$ = $\frac{3}{(20 + 10)}$ = $\frac{3}{30}$ = 0.1A

φ = $\frac{20 \times 0.1}{10}$ = 0.2 V/m