Physics for IGCSE & O level - Magnets And Currents (Section 8 - No. 7)
What can be used to strengthen an electromagnet?
Using a stronger current.
Increasing the number of turns in the coil.
Using a material with high permeability for the core.
Decreasing the current.
Обяснение
More current, more turns, and a high permeability material will strengthen the electromagnet.