A student makes a short electromagnet by winding 200 turns of wire around a non conducting cylinder of diameter, d= 4 cm . A current of 5 A is passed through the wire . Find the magnetic dipole moment of the device `x, xgt gt d` , on its axis the magnetic field of the dipole is `4 mu T` ?

Explanation

Dipole moment = m = ni A.] Axial line , `B = (mu_0 2m)/(4pi x^3)`