Chapter 7 Magnetism

Front

What happens when like poles of magnets are brought together?

Back

They repel each other.

Front

What happens when opposite poles of magnets are brought together?

Back

They attract each other.

Front

What is a commutator in a motor?

Back

A device that reverses the direction of current in the armature.

Front

How can you increase the strength of an electromagnet?

Back

By adding more coils of wire, using an iron core, or increasing the current.

Front

Why can a magnet pick up a nail but not a penny?

Back

Because the nail contains iron, which is magnetic.

Front

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

Back

A permanent magnet maintains its magnetic properties, while an electromagnet's magnetism can be turned on and off.

Front

What is the magnetic north pole?

Back

The point on the Earth's surface where the magnetic field points vertically downwards.

Front

Is the magnetic north pole the same as the geographic north pole?

Back

False.

Front

What materials are typically attracted to magnets?

Back

Materials that contain iron, nickel, or cobalt.

Front

What is the role of an armature in a motor?

Back

It is the rotating part of the motor that interacts with the magnetic field.