JEE Main202330 Jan 2023Morning ShiftPhysicsMagnetic Effects of CurrentActual
The magnetic moments associated with two closely wound circular coils A and B of radius r A = 10 cm and r B = 20 cm respectively are equal if: (Where N A , I A and N B , I B are number of turn and current of A and B respectively)
Options
- A2 N A I A = N B I B
- BN A = 2 N B
- CN A I A = 4 N B I B
- D4 N A I A = N B I B
Correct answer
C. N A I A = 4 N B I B
Step-by-step solution
As magnetic moment of both the coil is the same, μ 1 = μ 2 ⇒ N A I A π r A 2 = N B I B π r B 2 2 ⇒ N A I A 0 . 10 2 = N B I B 0 . 20 2 ⇒ I A N A = 4 I B N B