Question

A current carrying loop is free to turn in a uniform magnetic field. The loop will then come to equilibrium when its place is inclined at

• A. $0^o$ to the direction of field
• B. ${90}^o$ to the direction of field
• C. ${45}^o$ to the direction of field
• D. ${135}^o$ to the direction of field

Answer 1

The correct option is A $0^o$ to the direction of field

A stable equilibrium is when the net torque on the loop and potential energy is minimum. It is when the magnetic moment of the loop is along the direction of field.

$Torque=M\times B=MB\sin 0=0\left(equilibrium\right)$