Magnetic Field of a Solenoid
Mohan tightly wound a very long copper wire on a PVC pipe and carefully took the pipe out. The two ends of the copper wire then attached to a battery.
This cylindrical shape of copper wire showed few properties of a bar magnet. Later he found that it is called a solenoid and this solenoid is used in several devices such as door bell, relay switch etc. The magnetic field of a solenoid is given below.
The magnetic field strength of a solenoid having n turns is `B=mu_0nl`, where, `I` is the current flowing in the solenoid.
An electromagnet is made up by introducing a soft iron core having magnetic permeability `mu_r` in the solenoid. The magnetic field strength of solenoid becomes
Options:
(a) `mu_0I`
(b) `mu_0nI^2`
(c) `mu_0mu_rnI`
(d) None of these