Torques `tau_(1)` and `tau_(2)` are required for a magnetic needle to remain perpendicular to the magnetic fields at two different places. The magnetic field at those places are B1 and B2 respectively, then `(B_(1))/(B_(2))` is

Options

A. `(tau_(2))/(tau_(1))`
B. `(tau_(1))/(tau_(2))`
C. `(tau_(1)+tau_(2))/(tau_(1)-tau_(2))`
D. `(tau_(1)-tau_(2))/(tau_(1)+tau_(2))`

Answer

b

Explanation

(b) `tau MB sin theta (theta=90^(@))`
`tau=MB rArr (B_(1))/(B_(2))=(tau_(1))/(tau_(2))` (since magntic moment is same)