Electromagnets year 8

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

• A circular shape

• A diamond shape

• A square shape

• An oval shape

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

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

Which of the following is a 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

Which of the following uses an electromagnetic effect?

• Iron

• Light bulb

• Toaster

• Washing machine

An electromagnet on a crane 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

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

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