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 ( N _A, I _A . and N _ B , I _ B are number of turns and current of A and B respectively)

Step-by-step solution

array ll & We know that, m = NIA & Given that, m _ A = m _ B & N _ A I _ A A _ A = N _ B I _ B A _ B & N _ A I _ A [ ( R _ A )^2 ]= N _ B I _ B [ ( R _ B )^2 ] & N _ A I _ A (0.1)^2= N _ B I _ B (0.2)^2 & ~N _ A I _ A =4 ~N _ B I _ B array