question_answer 23)

A uniform magnetic field of 3000 G is established along the positive z-direction. A rectangular loop of sides 10 cm and 5 cm carries a current of 12 A. What is the torque on the loop in the different cases shown in Figure? What is the force on each case? Which case corresponds to stable equilibrium?  

Answer:

Using and , we get for                 (a)                 in direction.                 Force is zero.                 Similarly for other cases                 (b) Torque m in direction, force zero.                 (c) Torque in direction, force zero.                 (d) Torque force zero.                 (e) Torque zero, (stable equilibrium) because flux passes through vacancy of the coil and force zero.                 (f) Torque zero, (unstable equilibrium) because flux passes through vacancy of the coil and force zero.