PHYSICS · Multi-part · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism
Problem
A circular coil consists of 25 closely wound turns, each of radius 8cm. The coil is required to generate a magnetic field of 2×10−4T at its centre.
(i) Obtain, in symbolic form, an expression for the current needed in the coil in terms of the required magnetic field, number of turns, and radius.
(ii) Using your expression from part (i), calculate the current that must be supplied to the coil.
(iii) If the radius of the coil is reduced to 4cm while the current found in part (ii) is kept unchanged, determine the new magnetic field at the centre.