In the secondary circuit of a potentiometer , a cell of internal resistance `1.5 Omega` gives a balancing length of 52 cm. To get a balancing length of 40 cm , how much resistance is to be connected across the cell ?

Explanation

To solve the problem step by step, we will follow the given information and apply the relevant formulas.

### Step 1: Identify the given values
- Internal resistance of the cell, \( r = 1.5 \, \Omega \)
- Balancing length for the first condition, \( l_1 = 52 \, \text{cm} \)
- Balancing length for the second condition, \( l_2 = 40 \, \text{cm} \)

### Step 2: Understand the relationship between resistance and balancing lengths
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