Question

8. Which of these are not properties of
electromagnets?
(i) An increase in current increases its
strength.
(ii) They are permanent magnets.
(iii) They remain magnetised even after
the current is switched off.
(iv) They are of varying shapes and
sizes.
a) (i) and (ii)
c) (i) and (iv)
b)(ii) and (iii)
d) (ii) and (iv)​

Answer 1

Answer:

An electromagnet is a temporary magnet. It retains it magnetic property as long as electric current is passed through its solenoid. A soft iron core is used in the electromagnet because it loses its magnetization as soon as current is removed from it. It has a very strong magnetic field. Since it consists of a solenoid, the strength of field and also the direction is changed by changing current.

Answer 2

(i) An electromagnet is temporary in nature. (ii) An electromagnet is made of a soft iron core. (iii) The magnetic field strength can be changed. (iv) An electromagnet can be easily demagnetized by switching off the current.