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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 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
Options
A
B
A if the current is small, and B if the current is large
B if the current is small and A if the current is large
Solution
A
Explanation -
When we see from point A, the direction of the current will be anticlockwise and when we see the direction of current from point B then it will be clockwise. It means current is flowing as shown in the figure given below.
By right-hand thumb rule, the magnetic field lines will be in the direction from point B to A.
We also know that the magnetic field lines emerge from the North Pole and merge at the South Pole outside the magnet.
Hence, in this circuit face, A represents North pole and face B represents south pole.
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