The frequency of vibration in a vibration magnetometer of the combination of two bar magnets of magnetic moments ` M_(1) and M_(2)` is 6 Hz when like poles are tied and it is 2 Hz when the unlike poles are tied together, then the ratio `M_(1):M_(2)` is

Options

A. `4:5`
B. `5:4`
C. `1:3`
D. `3:1`

Answer

B

Explanation

By the sum and difference method of vibration magnetometer
`M_(1)/M_(2)=(T_(2)^(2)+T_(1)^(2))/(T_(2)-T_(1)^(2))`
time period `=(1)/(Frequency)`
` T_(1)=(1)/(n_(1))=(1)/(6)s`,
`T_(2)=(1)/(n_(2))=(1)/(2)s`
`(M_(1))/(M_(2))=(1/4+1/36)/(1/4-1/36)=10/8=5/4`