Q. A magnet 20 cm long with its poles concentrated at its ends is placed vertically with its north pole on the table. At a point due 20 cm south (magnetic) of the pole, a neutral point is obtained. If $H =$0.3 G, then the pole strength of the magnet is approximately
A) 185 ab-amp-cm
B) 185 amp-m
C) 18.5 ab-amp-cm
D) 18.5 amp-cm
Explanation
(a) $NS$ is a magnet held vertically with its north pole on the table. $P$ is neutral point, where $NP = 20$ cm, figure. Clearly,
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Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.