Question

Two concentric coils carry the same current in opposite directions. The diameter of the
outer coil is twice as compared to the inner coil. If at its centre, the smaller coil produces
a magnetic field of 2T, then, the magnetic field at the common centres is:
(A) 4T
(B) 3T
(C) 2T
(D) 1T​

Answer 1

Answer:

I think B) is the answer

Answer 2

Answer:

answer is d

Explanation:

b small coil= 2t given

• b coil quater= meu0I/ 2x2r=1t
• b net= 1t