Question
Question: A bar magnet with it's poles 25 *cm* apart and of pole strength 24 *amp*×*m* rests with it'scentre o...
A bar magnet with it's poles 25 cm apart and of pole strength 24 amp×m rests with it'scentre on a frictionless pivot. A force F is applied on the magnet at a distance of 12 cm from the pivot so that it is held in equilibrium at an angle of 30° with respect to a magnetic field of induction 0.25 T. The value of force F is
A
5.62 N
B
2.56 N
C
6.52 N
D
6.25 N
Answer
6.25 N
Explanation
Solution
In equilibrium
Magnetic torque = Deflecting torque
⇒ MBsinθ=F.d or F=dmlBsinθ