The directions of current flowing in the coil of an electromagnet at its two ends X and Y are as shown below:
(a) What is the polarity of end X?
(b) What is the polarity of end Y?
(c) Name and state the rule which you have used to determine the polarities.
The easy way to find the polarity is right-hand rule: " If the current flows in the direction of your fingers, the thumb points towards the north pole".
If we assume an electromagnet which has two ends i.e. X and Y, then,
(a) South is the polarity of end X as direction of current flow from that end is clockwise.
(b) The end Y will be the north pole as the current flow from this end shows the anticlockwise direction.
(c) The rule used here to find the polarity of the ends is clock face rule. According to this rule if the face from where it is being observed is showing the flow of current in anticlockwise direction then that end is N-pole but if the same face shows the flow of current in a clockwise direction then that end becomes S-pole.