Question

The following diagram shows a fixed coil of several turns connected to a center zero galvanometer G and a magnet NS which can move in the direction shown in the diagram.

1. Describe the observation in the galvanometer if
   1. The magnet is moved rapidly,
   2. The magnet is kept still after it has moved into the coil
   3. The magnet is then rapidly pulled out the coil.
2. How would the observation in (i) of part (a) change if a more powerful magnet is used?

Answer 1

1. 1. When the magnet is moved rapidly in the direction of arrow, the magnetic flux linked with the coil changes and there is a deflection in the galvanometer, indicating a flow of current through the coil.
   2. On keeping the magnet still, the magnetic flux linked with the coil does not change and there is no deflection in the galvanometer, indicating that no current is flowing through the coil.
   3. When the magnet is rapidly pulled out, there is again change in the magnetic flux linked with the coil and the galvanometer shows a deflection but this time in opposite direction, indicating that a current is flowing in opposite direction in the coil.
2.  If a more powerful magnet is used, deflection in the galvanometer will be large, indicating a greater amount of current.