Page 485 - Basic Electrical Engineering

or,

or,

If the length of the solenoid is large as compared to its radius, r then, the
flux density at the centre of the solenoid is

Example 5.1 A single turn coil of radius 10 cm is carrying a current of
100A. Calculate (i) the flux density at the centre of the coil; (ii) the flux

density in the perpendicular plane at a distance of 5 cm from the coil.

Solution:

Earlier we had calculated the magnetic field strength at the centre of a

current-carrying coil of single turn as

With air as the medium, the flux density at the centre