Four wires each of length 2 m are bent in the form of four loops P, Q, R and S as shown below. They are suspended in a uniform magnetic field. Each loop carries the same current. Identify the correct statement.

1. torque on loop P is maximum.
2. torque on loop Q is maximum.
3. torque on loop R is maximum.
4. torque on loop S is maximum.

How will the direction of force be changed, if the current is reversed in the conductor placed in a magnetic field?

A current flows through a wire in a south to north direction and the magnetic field is directed downwards. In what direction will the force act on the wire?

A proton moving towards East enters in a uniform magnetic field directed downwards. Find the direction of the force acting on it.