A laboratory electromagnet is constructed by winding a closely packed solenoid over a…
PHYSICS · Multi-part · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism
Problem
A laboratory electromagnet is constructed by winding a closely packed solenoid over a 25cm long soft-iron rod of circular cross-section. The solenoid has 1500 turns.
(i) Calculate the magnetic field at the centre of the rod when a current of 2.0A flows through the winding. Assume the rod is absent (air core).
(ii) The soft-iron rod of relative permeability μr=1200 is now in place while the same current flows. Find the new magnitude of the magnetic field.
(iii) Keeping the rod in position, determine the current required to obtain a magnetic field of 1.5T at the centre.