A potentiometer wire of length 1 m has a resistance of `10Omega`. It is connected to a 6V battery in series with a resistance of `5Omega`. Determine the emf of the primary cell which gives a balance point at 40cm.

Explanation

To solve the problem step by step, we will follow these calculations:

### Step 1: Understand the Circuit Configuration
We have a potentiometer wire of length 1 meter (100 cm) with a resistance of 10 Ω. It is connected to a 6V battery in series with a 5Ω resistor. We need to find the EMF of a primary cell that gives a balance point at 40 cm on the potentiometer.

### Step 2: Calculate the Total Resistance in the Circuit
The total resistance \( R_{total} \) in the circuit is the sum of the resistance of the potentiometer wire \( R_0 \) and the series resistor \( R \):
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