Question

Two coils are wound on a non-conducting cylindrical rod as shown in the figure. Initially, the key is open. Now, if the key is closed and later set as open,

Options

• the deflection in the galvanometer will remain zero.

• there will be a momentary deflection in the galvanometer, but it dies out shortly and there is no effect when the key is set open.

• there are momentary galvanometer deflections that die out shortly; the deflections are in the same direction.

• there are momentary galvanometer deflections that die out shortly; the deflections are in opposite directions.

Answer 1

There are momentary galvanometer deflections that die out shortly; the deflections are in opposite directions.

Explanation:

Closing the key causes a sudden increase in current (inducing current in one direction), while opening it causes a sudden decrease (inducing current in the opposite direction).