Torque

Step 1: Recall the expression for torque ( ) acting on a magnetic dipole ( ) placed in a uniform magnetic field ( ):

where is the angle between the magnetic dipole axis and the direction of the magnetic field.

Step 2: Determine when torque is zero.

The torque will be zero if:

This occurs when:

Step 3: From the given options, angle satisfies the above condition.

Final Conclusion:
The torque on the magnetic dipole is zero when the angle between the dipole axis and the magnetic field is zero degrees (0°).