A closely wound solenoid of 800 turns and area of cross section `2.5 xx 10^(-4) m^(2)` carries a current of 3.0 A. Explain of the sense in which the solenoid acts like a bar magnet. What is its associated magnetic moment ?

Explanation

Here `n = 800, a = 2.5 xx 10^(-4) m^(2), I = 3.0A`
A magnetic field develop along the axis of the solenoid. Therefore the current carrying solenoid behaves like a bar magnet
`m = NIA = 800 xx 3.0 xx 2.5 xx 10^(-4)`
`= 0.6 A m^(2)` along the axis of solenoid.