Electromagnets

A hard ferromagnetic material like steel would make a very bad electromagnet because __________.

• it is too heavy

• its domains would never line up

• you couldn't turn it off

A metal, such as iron, that can be easily magnetized, but won't stay that way for long is called __________.

• soft ferromagnetic

• hard ferromagnetic

• paramagnetic

A wrapped coil that you pass a current through to produce a magnetic field is called a __________.

• solenoid

• solvent

• solar plexus

An electromagnet is a metal that __________.

• can be permanently magnetized

• is only magnetized when it's exposed to an electrical current, and then stops being a magnet when the current is gone

• can not be magnetized by an electric current

Collections of atoms with magnetic fields that all point in the same direction are called __________.

• magnetic domains

• magnetites

• magnetic charges

Electromagnets are used in __________.

• photosynthesis

• electric motors

• solar panels

When electric current is run through a solenoid coil that is wrapped around a chunk of iron, __________.

• just the iron becomes magnetized

• the whole thing, coil and iron, becomes a powerful magnet

• the iron melts

An electromagnet is needed in order for ________ to run.

• a car

• an airplane

• an electric train

• a subway

• all of the above

As electrons circle around the nucleus of an atom, they _______.

• create a magnetic domain

• induce a magnetic field

• spin out of control

• become aligned

Which statement is true about the piece of metal in the picture?

• All of the magnetic fields are aligned.

• The atoms occupy many different magnetic domains.

• It is a magnet.

• The electrons are not moving.