Question
Physics Question on Magnetic Effects of Current and Magnetism
A magnetic dipole aligned parallel to a uniform magnetic field requires a work of W units to rotate it through 60°. The torque exerted by the field on the dipole in this new position is:
A
2W
B
W
C
23W
D
3W
Answer
23W
Explanation
Solution
The torque τ on a magnetic dipole in a magnetic field is given by:
τ=MBsinθ
where M is the magnetic moment, B is the magnetic field, and θ is the angle between the dipole and the field.
Given that the angle θ=60∘, the torque becomes:
τ=MBsin60∘=MB×23
Thus, the torque is 23W, which corresponds to option 3.