A bar magnet of length 10 cm and pole strength 2 A m makes an angle `60^(@)` with a uniform magnetic field of induction 50 T. The couple acting on it is

Explanation

Length of the bar magnet , 2l=10cm = 0.1 m
pole strength , m =2Am
magnetic induction , B=50T
Angle between the magnetic filed and axis of the magnet ,` theta =60^(@)`
`:.`Couple acting on the bar magnet,` tau = MB sin theta `
`implies tau = (2 l xx m)B sin theta = ( 0.1 xx 2 ) 50 sin 60^(@)`
`= 0.2 xx 50 xx (sqrt(3))/(2) = 6.66 N-m`