Question

In the meter bridge experiment, the null point is obtained at a distance of ℓ from the left end. The resistance in the left and right gaps are halved and then interchanged. The new position of the null point is at ______

Options

• (100 - ℓ) from left end

• (100 - 2ℓ) from left end

• `(100 - ℓ/2)` from the left end

• (100 - 4ℓ) from the left end.

Answer 1

In the meter bridge experiment, the null point is obtained at a distance of ℓ from the left end. The resistance in the left and right gaps are halved and then interchanged. The new position of the null point is at (100 - ℓ) from the left end.

Explanation:

When the resistance is interchanged the lengths are also interchanged. Halving of the length does not matter because the ratio remains the same. Therefore the new position of the null point will be at (100 - ℓ) from the left end.