A straight wire of length l can slide on two parallel plastic rails kept in a horizontal plane with a separation d. The coefficient of friction between the wire and the rails is `mu`. If the wire carries a current I, what minimum magnetic field should exist in the space in order to slide the wire on the rails.

Answer

A, B

Explanation

Minimum required force to overcome friction
`(mumg)/sqrt(1+mu^(2))=Bilsin thetarArrB=(mumg)/(ilsqrt(1+mu^(2) sin theta) )rArrB_(min)=(mumg)/(ilsqrt(1+mu^(2)))`