Two bar magnet with magnetic moment `2M` and `M` are fastened togather at right angles to each other at their centres to from a cross system, which can rotate freely about a vertical axis through the centre. The crossed system sets in earth's magnetic field with magnet having magnetic moment `2M` making and angle `theta` with the magnetic merdian such that

Options

A. `theta= tan^(-1) ((1)/(sqrt3))`
B. `theta= tan^(-1) (sqrt3)`
C. `theta= tan^(-1) ((1)/(2))`
D. `theta= tan^(-1) ((3)/(4))`

Answer

C

Explanation

`tan theta= (M)/(2M)`
`rArr theta= tan^(-1) (1//2)`