Question

Two students X and Y perform potentiometer experiment separately and null point was obtained as shown in diagram. During the experiment, ______.

1. X increases the value of R (resistance)
2. Y decreases the value of S (resistance)

The position of null point obtained by students X and Y respectively.

Options

• would shift towards point B, would shift towards A

• would shift towards B by both X and Y

• would shift towards point A, would shift towards B

• would shift towards A by both X and Y

Answer 1

Two students X and Y perform potentiometer experiment separately and null point was obtained as shown in diagram. During the experiment, would shift towards point B, would shift towards A.

Explanation:

1. With R increase, the current I will decrease, so potential gradient will increase. So larger length will be required for a null point.
2. When S is decreased the current drawn from E₁ increases. So V = E₁ - Ir, the potential difference across E₁ will decrease. This new potential difference will be balanced by a smaller length of potentiometer wire.