Electromagnets 01

1. The magnetic field around a straight wire carrying an electric current has .......

   • A circular shape
   • A diamond shape
   • A square shape
   • An oval shape

2. The magnetic field around a coil of wire carrying current .......

   • Is a circular shape
   • Is a diamond shape
   • Is a square shape
   • Is the same shape as around a bar magnet

3. If the current direction through the wire is reversed, the direction of the magnetic field .......

   • Is also reversed
   • Stays in the same direction
   • The current stops flowing
   • There is no magnetic field

4. If the current in the wire increases, what happens to the strength of the magnetic field?

   • It decreases
   • It increases
   • It stops the magnetic field
   • No change

5. Which of the following is NOT true about the magnetic field around a coil of wire carrying a current?

   • Changing the direction of the current will reverse the poles
   • Increasing the number of coils will increase the strength
   • Making the coil wider will increase the strength
   • Putting an iron core into the coil will increase the strength

6. What is the difference between an electromagnet and a permanent bar magnet?

   • Electromagnets are stronger
   • Electromagnets can be turned off
   • Permanent magnets are stronger
   • Permanent magnets can be turned off

7. Which of the following uses an electromagnetic effect?

   • Iron
   • Light bulb
   • Toaster
   • Washing machine

8. A relay uses a small current to .......

   • Attract a magnet
   • Repel a magnet
   • Switch off a current
   • Switch on a larger current

9. A relay is used in .......

   • A car ignition
   • An electric bell
   • An electric cooker
   • An iron

10. An electromagnet is used in a scrapyard because .......

    • It can be turned on and off
    • It can't be turned on and off
    • It is stronger than a permanent magnet
    • It is weaker than a permanent magnet

Quiz written by Sue Davison