PHYSICS · Subjective · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism
Problem
Two identical coaxial circular coils, each of N turns and radius R, are placed parallel to each other at a separation equal to R. Both coils carry the same current I in the same direction.
(a) Obtain an expression for the net magnetic field at a point on the common axis located at a distance x from the midpoint of the line joining the centres of the coils.
(b) Show that the first derivative of this field with respect to x vanishes at the midpoint, and hence comment on the nature of the field in the neighbourhood of this point.
(c) Calculate the magnitude of the field at the midpoint for N=150, R=0.30m and I=2.0A, taking μ0=4π×10−7TmA−1.