Question

The metre bridge shown is in balance position with
Р/Q=l1/l2. If we now interchange the positions of
galvanometer and cell, will the bridge work? If
yes, what will be balance condition?
[NEET-2019 (Odisha)]

1) yes, Р/Q=l1/l2

2) yes, Р/Q=l2-l1/l2+l1


3) no, no null point

4) yes, Р/Q=l2/l1​

Answer 1

Given:

The metre bridge shown is in balance position with  Р/Q=l1/l2.

To find:

If we now interchange the positions of  galvanometer and cell, will the bridge work? If yes, what will be balance condition?

Solution:

From given, we have,

The metre bridge is in a balanced position with Р/Q = l1/l2.

When we interchange the positions of  galvanometer and cell, the metre bridge will remain in a balanced position with the current drawn from the battery being zero.

So, the meter bridge will work.

As, P ∝ I1 and Q ∝ I2, the condition will remain the same as Р/Q = l1/l2 after interchanging the positions of galvanometer and cell.

Option 1) yes, Р/Q = l1/l2 is correct.