The diagram below shows a magnetic compass kept closer to a coil AB wound around a hollow cylindrical cardboard :
(a) After studying the circuit and the magnetic compass carefully, state whether the switch S1 is open or closed.
(b) How did you arrive at the conclusion in (a)?
(c) What is the purpose of placing the magnetic compass in the above setup?
Show SolutionHide Solution↓
(a) The switch S1 is closed.
(b) When the key is pressed, a current passes in the wire in the direction from A to B (i.e. from south to north) and the north pole (N) of the needle deflects towards the west. There is a deflection in the magnetic compass. So, it is concluded that the switch S1 is closed and current is flowing through the coil.
(c) The purpose of placing the magnetic compass is to determine the polarity developed at the end A of the solenoid.