A bar magnet `A` of magnetic moment `M_(A)` is found to oscillate at a frequency twice that of magnet `B` of magnetic moment `M_(B)` when placed in a vibrating magneto-meter. We may say that

Options

A. `M_=2M_(B)`
B. `M_(A)=8M_B`
C. `M_(A)=4M_(B)`
D. `M_(B)=8M_(A)`

Answer

C

Explanation

`v=1/(2pi)sqrt((MB_(H))/I)implies v prop sqrt(M)`
`implies v_(A)/V_(B)=sqrt(M_(A)/M_(B)) implies2/1=sqrt(M_(A)/M_(B))implies M_(A)=4M_(B)`