(A) : The magnetic field at the centre of a circular coil carrying current could be calculated using Amperes law.
(R) : Biot savart law could be derived from Amperes law.

Options

A. Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'.
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. 'A' is true and 'R' is false
D. 'A' is false and 'R' is false

Answer

B