Question
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)
BITSAT
Physics
Magnetic Effects of Current
2023
BITSAT 2023 (Memory Based Paper 2)
BITSAT Physics Question (2023) — Solution
Options
- A. 2 ~N _ A I _ A = N _ B I _ B
- B. N _ A =2 ~N _ B
- C. N _ A I _ A =4 ~N _ B I _ B
- D. 4 ~N _ A I _ A = N _ B I _ B
Answer
C. N _ A I _ A =4 ~N _ B I _ B
Step-by-step solution
The magnetic moment associated with circular coil, aligned & M=N I A \\ & M_A=M_B \\ & N_A I_A A_A=N_B I_B A_B \\ & N_A I_A (0.1)^2=N_B I_B (0.2)^2 ( A= r^2 ) \\ & N_A I_A=4 N_B I_B aligned
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