question_answer

A current carrying coil is placed with its axis perpendicular to N-S direction. Let horizontal component of earth's magnetic field be \[{{H}_{0}}\] and magnetic field inside the loop be H. If a magnet is suspended inside the loop, it makes angle \[\theta \] with H. Then \[\theta \]=

A) \[{{\tan }^{-1}}\left( \frac{{{H}_{0}}}{H} \right)\]

B) \[{{\tan }^{-1}}\left( \frac{H}{{{H}_{0}}} \right)\]

C) \[\cos e{{c}^{-1}}\left( \frac{H}{{{H}_{0}}} \right)\]

D) \[{{\cot }^{-1}}\left( \frac{{{H}_{0}}}{H} \right)\]

Correct Answer: A

Solution :

[a] \[\tan \,\theta =\frac{{{H}_{0}}}{H}\] \[\theta ={{\tan }^{-1}}\left( \frac{{{H}_{0}}}{H} \right)\]