Question

State one way in which an electromagnet is different from a permanent bar magnet.

Answer 1

The polarity of the electro magnet can be changed by changing the direction of current, but we can not do so in a bar,its poles are fixed

Answer 2

permanent magnet has fix magnetic field
solenoid mf can be altered by changing number of turns current through it etc
electromagnetic mf is much heigher than bar magnet
electronic mf caan be reduced to zero while bar magnet mf can not be reduced to zero