In an experiment with a potentiometer, the null point is
obtained at a distance of `60 cm` along the wire from the
common terminal with a leclanche cell. When a shunt
resistance of `1 Omega` is connected across the cell, the null
point shifts to a distance of `30 cm` from the common
terminal. what is the internal resistance of the cell?

Explanation

To find the internal resistance of the cell in the given potentiometer experiment, we can follow these steps:

### Step 1: Understand the Problem
We have a potentiometer setup where the null point is initially at a distance of 60 cm from the common terminal with a Leclanché cell. When a shunt resistance of 1 ohm is connected across the cell, the null point shifts to 30 cm.

### Step 2: Identify the Variables
- Let \( L_1 = 60 \, \text{cm} \) (the initial null point distance)
- Let \( L_2 = 30 \, \text{cm} \) (the null point distance after connecting the shunt)
...