Question

In a potentiometer of $10$ wires, the balance point is obtained on the $7^{th}$ wire. To shift the balance point to $9^{th}$ wire, we should.

• A. Decrease resistance in the main circuit
• B. Increase resistance in the main circuit
• C. Decrease resistance in series with the cell whose emf is to be measured
• D. Increase resistance in series with the cell whose emf is to be determined

Answer 1

The correct option is B Increase resistance in the main circuit

In order to shift the balance point to the $9^{th}$ wire , the potential gradient of the wire should be decreased so that the balance point shifts further. This can happen when the current in the main circuit is decreased.

The current in the circuit can be decreased by increasing the resistance of the main circuit.

Therefore, option $B$ is correct.