A magnet is suspended in the magnetic meridian with an untwisted wire. The upper end of wire is rotated through `180^(@)` to deflect the magnet by `30^(@)` from magnetic meridian. When this magnet is replaced by another magnet, the upper end of wire is rotated through `270^(@)` to deflect the magnet `30^(@)` from magnetic meridian. The ratio of magnetic moment of magnets is

Options

A. `3:4`
B. `1:2`
C. `4:7`
D. `5:8`

Answer

D

Explanation

`C(180-30)=M_(1)B_(H) sin30-(1)`
`C(270-30)=M_(2)B_(H)sin30-(2)` Divided
`(M_(1))/(M_(2))=(5)/(8)`