mixture and solution

The magnet which is made by the effect of electricity is called

• a.      Natural magnet,

• b.     Magnetic substance.

• c.      Electromagnet.

• d.     (b) and (c)

Magnetic effect of the electric current can be detected by using

• a.      Ammeter.

• b.     Compass.

• c.      Iron filings.

• d.     both (b) and (c).

(1)        The idea of operative the electromagnet is the changing of ………..

• a.     Kinetic energy into electric energy.

• b.     Electric energy into mechanical energy.

• c.      Magnetic energy into

• .

  Electric energy into magnetic energy

(1)        The bar used in the electromagnet is made up of ………..

• a.      Aluminum.

• b.     Wrought iron.

• c.      Steel.

• d.     Copper.

(1)        The electromagnet is composed of ………..

• a.      A copper wire only.

• b.     A bar of wrought iron only.

• c.      A battery.

• d.     (a), (b) and (c).

(1)        ……….. (is) are from the uses of the electromagnet.

• a.      Moving the iron blocks in factories.

• b.     Making an electric mixer.

• c.      Making an electric generator.

  d

• .      (a) and (b).

(1)        The magnetic force of the electromagnet will be lost by:

• a.      Increasing the number of coil turns.

• b.     Increasing the number of batteries.

• c.      Cutting the electric current.

  d

• .     Switching on the key.

(1)        The magnetic force of the electromagnet increases by ………..

• a.     Increasing the number of coil turns only.

  (b).

• .     Increasing the intensity of the electric current only.

• .      Cutting off the electric current.

• d.     Both (a) and(b)

(1)        All the following devices have an electromagnet inside them except the ………..

• a.      Electric bell.

• b.     Television.

• c.      Disc drive.

• a.      Refrigerator.

When an electric current passes through a coil twisted around a wrought iron bare, the wrought iron bar becomes a ……….. magnet

• a.      Temporary.

• b.     Permanent.

  .

• c.      Natural.

• d.     (a) and (b)