e-mag

A current flowing through a wire produces a _______ ______.

which one is the strongest eletromagnet?

• 50 turns on the coil, low current,

  copper core

• 100 turns on the coil,

  high current,

  iron core

• 50 turns on the coil, low current,

  iron core

• 100 turns on the coil,

  low current,

  iron core

Looking at the field lines in this picture, these two magnets are ________.

• Attracting

• Repelling

• Attracting and Repelling

• Doing nothing

Are the magnetic field lines in the picture correct?

• Yes, because they point from north to south.

• No, because the North pole is on the left in all pictures (it's supposed to be on the right).

• No, because they point from north to south (they're supposed to go the other way).

• Yes, because the North pole is on the left in all pictures.

An electromagnet can be strengthened if _______________.

• a nickel or cobalt iron core is used.

• less coils are added to the iron core

• the iron core is removed

• more current runs through the wire

What causes the magnetic field to form in an electromagnet?

• The magnetic field is absorbed from another magnet

• Electromagnets are only called magnets because electricity is involved.

• The domains of the magnet become aligned

• Electric current flowing in a wire

The area of magnetic force around a magnet is known as its _____________.

• magnetic field

• magnetic fan

• magnetic force

How can the strength of an electromagnet be increased? (mark all that apply)

• increase the current flowing through the coil

• increase the number of coils

• add an amplifier to it

• put iron core inside the coil

This is a picture of a simple electromagnet. How can the electromagnet be made stronger?

• Add more coils of wire to the nail.
• Use a smaller battery.
• Reverse the poles of the magnet.
• Remove all the coils and the nail.

It is a kind of magnet that works only when there is a flow of electricity.

• Electromagnet

• Bar Magnet

• Horse Shoe Magnet

• Magnetite