A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 μA and subjected to a magnetic field of strength 0.85 T. Work done for rotating the coil by 180° against the torque is
(a) 4.55 μJ
(b) 2.3 μJ
(c) 1.15 μJ
(d) 9. 1 μJ
Correct option (d) 9.1 μJ
Explanation:
Putting these values in eqn. (i), we get
