Question

if there is a circular coil having n turns, the field produced is n times as large as that produced by a single turn.

Answer 1

Initial current= x

Final current =2x

Initial radius = r

Final radius =1/2 r

Formula,

Initial Magnetic field = B1=permeability of free space x current/2 pi x radius

Let , B1= k × I/ r

Final magnetic field =B2=k×2 ×I/2×r

B2=k×I/r

B2=B1

Hence there is no change in magnetic field