Two coils P and S are wound over the same iron core. Coil P is connected to battery and key and the coil S is connected to galvanometer. Write your observations when: (i) Current in the coil P is started by closing the key. (ii) Current continues to flow in coil P. (iii) Current in coil P is stopped by removing the key. Explain the reason for such observation.

Two coils P and S are wound over the same iron core. Coil P is connect

1.	Two coils P and S are wound over the same iron core. Coil P is connected to battery and key and the coil S is connected to galvanometer. Write your observations when: (i) Current in the coil P is started by closing the key. (ii) Current continues to flow in coil P. (iii) Current in coil P is stopped by removing the key. Explain the reason for such observation.
Answer» Solution : (i) There is DEFLECTION in galvanometer CONNECTED with coils, due to induced current. (ii) Deflection becomes zero. (ii)Deflection in galvanometer is in opposite direction. Reason: (i)E.M. INDUCTION TAKES place because field is changing (i) Since current becomes stationary, no change in field takes place. So no EM induction. (ii) E.M. induction takes place but induced current is in opposite direction.