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Question
Consider the situation shown in figure. If the closed loop is completely enclosed in the circuit containing the switch, the closed loop will show _______________ .
Options
an anticlockwise current-pulse
a clockwise current-pulse
an anticlockwise current-pulse and then a clockwise current-pulse
a clockwise current-pulse and then an anticlockwise current-pulse
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Solution
an anticlockwise current-pulse and then a clockwise current-pulse
According to Lenz's law, the induced current in the loop will be such that it opposes the increase in the magnetic field due to current flow in the circuit. Therefore, the direction of the induced current when the switch is closed is anti-clockwise.
Similarly, when the switch is open, there is a sudden fall in the current, leading to decrease in the magnetic field at the centre of the loop. According to Lenz's law, the induced current in the loop is such that it opposes the decrease in the magnetic field. Therefore, the direction of the induced current when the switch is open is clockwise.
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