Question

The diagram below shows a coil connected to a Centre zero galvanometer G. The galvanometer shows a deflection to the right when the N-pole of a powerful magnet is moved to the right as shown.

(i) Explain why the deflection occurs in the galvanometer.

(ii) Does the direction of current in the coil appear clockwise or anticlockwise when viewed from end A? 

(iii) State the observation in G when the coil is moved away from N. 

(iv) State the observation in G when, both coil and the magnet, are moved to the right at the same speed.

Answer 1

i. The deflection in the galvanometer occurs because of change in magnetic flux linked with the coil which results in formation of induced emf and further induced current due to the phenomena called electromagnetic induction. 

ii. The direction of current appears to be anti-clockwise from point A because at point A there is formation of North pole and at point B there is formation of South pole. 

iii. When the coil is moved away from north pole the direction of induced current gets reversed because point A now becomes South pole and point B now becomes North pole due to change in magnetic flux linked with the coil. So, the galvanometer will show deflection to the left side.

iv. There would be no observation change in galvanometer as the magnet and closed coil are moving with same speed and have no relative motion. For formation of induced emf, there must be relative motion between magnet and coil.