JAMB - Physics (2003 - No. 30)
I It retains its magnetic much longer than steel.
II It is more easily magnetized than steel
III It is more easily demagnetized than steel
IV It produces a stronger magnet than steel
Which combination of the above makes iron preferable to steel in the making of electromagnets?
II It is more easily magnetized than steel
III It is more easily demagnetized than steel
IV It produces a stronger magnet than steel
Which combination of the above makes iron preferable to steel in the making of electromagnets?
I and II only
II and III only
I, III, and IV only
II, III and IV only
Giải thích
Iron (soft iron) is usually preferred to steel in the making of electromagnets because it is more easily magnetized and equally more easily demagnetized than [II, III and IV]