question_answer 42)

  A circular loop placed in a plane perpendicular to the plane of paper carries a current when the key is ON. The current as seen from points A and B (in the plane of paper and on the axis of the coil) is anti-clockwise and clockwise respectively. The magnetic field lines point from B to A. The N-pole of the resultant magnet is on the face close to (a) A                                      (b) B (c) A if the current is small and B if the current is large (d) B if the current is small and A if the current is large

Answer:

                  (a) The N-pole of the resultant magnet is on the face close to A because, the magnetic field lines enter in loop from 6 and come out from A. Also, as a matter of fact magnetic lines come out of the N-pole of magnet. Therefore, face close to A represents N-pole. The currents in A and B are same.