Question

The potentiometer consists of wire of length $4m$ and resistance $10$ . It is connected to a cell of e.m.f $2V$. The potential difference per unit length of the wire will be

• A. $10V/m$
  
• B. $5V/m$
  
• C. $2V/m$
  
• D. $0.5V/m$
  

Answer 1

The correct option is D $0.5V/m$

Length of the wire $L=4m$

Emf of the cell $E=2V$

Potential difference across the wire is same as the emf of cell i.e. $2V$.

Thus potential difference per unit length $\frac{E}{L}=\frac{2}{4}=0.5V/m$