AB is a coil of copper wire having a large number of turns. The ends of the coil are connected with a…
AB is a coil of copper wire having a large number of turns. The ends of the coil are connected with a galvanometer as shown. When the north pole of a strong bar magnet is moved towards the end B of the coil, a deflection is observed in the galvanometer.
(a) State the reason for using galvanometer in the activity and why does its needle deflects momentarily when magnet is moved towards the coil.
(b) What would be observed in the galvanometer in a situation when the coil and the bar magnet both move with the same speed in the same direction ? Justify your answer.
(c) State the conclusion that can be drawn from this activity.
Will there be any change in the momentary deflection in the galvanometer if number of turns in the coil is increased and a more stronger magnet is moved towards the coil ?
Solution
(a)
Galvanometer is used to detect the presence of current along with its direction.
Needle deflects momentarily due to momentary change in magnetic field associated with the coil due to which current induces.
(b) There would be no deflection in the galvanometer because there is no induced current flowing in galvanometer as there is no relative motion between the magnet and the coil and no change in magnetic field associated with coil.
(c)
The relative motion of a magnet and coil produces an induced potential difference which sets up an induced current in the circuit and it lasts so long the relative motion is there.
Momentary deflection will be there with increased magnitude.
