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As shown in the figure, a bar magnet is moving towards a stationary coil with constant speed v. The direction of the induced current in the coil, as seen by the observer on the right-hand side, is __________.

Asked in GUJCET 2023 · Direction of the induced current

Figure: Direction of the induced current
Answer: (2) Clockwise

Step-by-step solution

Setup (figure): the N pole of the magnet faces the coil and approaches it from the left; the observer looks at the coil from the right.

Flux: the magnet's field at the coil points away from the N pole — to the right — and grows as the magnet comes closer.

Lenz's law: the induced current opposes this increase, so inside the coil it sets up a field pointing to the left; the face of the coil nearer the magnet becomes a north pole and repels it.

The observer on the right looks towards the left, so this induced field points away from the observer.

A current whose field points away from the viewer circulates clockwise as seen by that viewer.

So the observer on the right-hand side sees a clockwise current.

Why the other options are wrong

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