The magnetic strength of an electromagnet can not be changed.
Which of the following changes the strength of the magnetic field created by an electromagnet
The strength of the magnetic field between the poles of an electromagnet would be unchanged if :
(a) current in the electromagnet winding were doubled
(b) direction of current in electromagnet winding were reversed
(c) distance between the poles of electromagnet were doubled
(d) material of the core of electromagnet were changed
The strength of an electromagnet can be increased by