KCET2011PhysicsMagnetic Effects of Current
The torque required to hold a small circular coil of 10 turns, area 1 ~mm ² and carrying a current of ( 21 44 ) A in the middle of a long solenoid of 10³ turns/m carrying a current of 2.5 ~A , with its axis perpendicular to the axis of the solenoid is
Options
- A1.5 10⁻⁶ ~N - m
- B1.5 10⁻⁸ ~N - m
- C1.5 10⁺⁶ ~N - m
- D1.5 10⁺⁸ ~N - m
Correct answer
B. 1.5 10⁻⁸ ~N - m
Step-by-step solution
We have, M=N I A B= ₀ n I Here, C= (n₁ I₁ A ) ( ₀ n₂ I₂ )= (10 21 44 10⁻⁶ ) (4 22 7 10⁻⁷ 10³ 2.5 )=1.5 10⁻⁸ N-m Torque, C=M B