Physics for IGCSE & O level - Magnets And Currents (Section 12 - No. 4)
How is the strength of an electromagnet increased?
By using a stronger core material.
By adding more coils of wire.
By increasing the current through the coil.
By decreasing the number of coils.
Explication
Increasing the current, the number of coils, and using a stronger core material increase the strength.