question_answer

At some location on earth the horizontal component of earth's magnetic field is \[18\times {{10}^{-6}}T.\] At this location, magnetic needle of length 0.12 m and pole strength 1.8 Am is suspended from its mid - point using a thread, it makes \[45{}^\circ \] angle with horizontal in equilibrium. To keep this needle horizontal, the vertical force (in N) that should be applied at one of its ends is:

Answer:

\[\left( 6.5\times {{10}^{-5}} \right)\]