question_answer

Figure shows a bar magnet and two infinite long wires \[{{W}_{1}}\] and \[{{W}_{2}}\] carrying equal currents in opposite directions. The magnet is free to move and rotate. P is the mid-point of magnet. For this situation mark out the correct statements),                

A)  Magnet experiences a net torque in clockwise direction and zero net force.

B)  Magnet experiences a net force towards left and a net torque in anti-clockwise direction.

C)  Magnet experiences a net force towards right and a net torque in anti-clockwise direction.

D)  Magnet experiences zero net force and a net torque in anti-clockwise direction.

Correct Answer: C

Solution :

 Both the poles of the magnet experience a force due to magnetic field produced by wires \[{{W}_{1}}\] and \[{{W}_{2}}\]. North pole experiences a force \[{{F}_{1}}\] due to \[{{W}_{1}},\] and \[{{F}_{2}}\] due to \[{{W}_{2}}\] as shown in figure. Similarly, south pole experiences a force \[{{F}_{1}}\] due to \[{{W}_{2}}\] and \[{{F}_{2}}\] due to \[{{W}_{1}}\]. From free body diagram of magnet, it is clear that magnet experiences a net force towards right and a torque in anti-clockwise direction.