Question

In potentiometer experiment, for a given current, the balancing length for a cell is obtained at \( L \) cm. If the current through potentiometer wire is decreased, then the balancing length will

• A. be increased.
• B. not be changed.
• C. become half.
• D. be decreased.

Hint:

In a potentiometer experiment, decreasing the current results in an increase in the balancing length, since the potential difference across the wire is reduced.

Answer 1

The Correct Option is A

Step 1: Understanding the potentiometer principle.
In a potentiometer experiment, the balancing length \( L \) is directly proportional to the potential across the wire, which in turn is proportional to the current flowing through the wire. Step 2: Effect of changing the current.
If the current is decreased, the potential difference across the wire also decreases, but the potential difference per unit length decreases. Therefore, the balancing length \( L \) must increase to balance the potential of the cell. Step 3: Conclusion.
Thus, if the current through the potentiometer wire is decreased, the balancing length will increase, which corresponds to option (A).