QQuestion
When the magnet shown in the diagram is moved towards the coil at a speed of 5 m s−1, the galvanometer shows a certain deflection to the right.
How will the direction and magnitude of deflection change when the coil also moves with a speed of 5 m s−1:
(a) in the direction of motion of the magnet?
(b) in the opposite direction to the motion of the magnet?
✓Answer
The galvanometer deflection depends on the rate of change of magnetic flux and hence on the relative motion between the magnet and coil.
(a) The magnet and coil move in the same direction at the same speed, so there is no relative motion. No current is induced and the galvanometer shows no deflection.
(b) The magnet and coil move in opposite directions, so their relative speed is 10 m s−1. The direction of deflection remains to the right, but its magnitude increases.
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