Question

In a potentiometer arrangement, a cell of 1.5 V gives a balance point at 45.0 cm length of the wire. If the cell is replaced by another cell and the balance point shifts to 75.0 cm, what is the emf of the second cell?

• A. 2.5 V
• B. 1.0 V
• C. 3.1 V
• D. 1.5 V

Hint:

In a potentiometer, the emf of a cell is proportional to the length of the wire at the balance point.

Answer 1

The Correct Option is B

In a potentiometer, the emf is directly proportional to the length of the wire at the balance point. Let the emf of the second cell be \(E_2\). From the given information: \[ \frac{1.5 \, \text{V}}{45.0 \, \text{cm}} = \frac{E_2}{75.0 \, \text{cm}} \] Solving for \(E_2\): \[ E_2 = \frac{1.5 \times 75.0}{45.0} = 1.0 \, \text{V} \]