Question

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 the 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 1

The correct option is A A

From right hand thumb rule, it can be shown that magnetic lines of force emerge out from face close to A, and go into the face close to B.
Factually, the magnetic fields emerge from north pole of magnet, and go into the south pole. Hence the correct answer is option A.