Making Magnets with Electric Current

What type of magnet that can turned on and off?

• electromagnet

• permanent magnet

• electricity

• battery

Why does a compass needle move when electricity flows through a coiled wire?

• Because a magnetic field is not produced, which does not attract the needle.

• Because a magnetic field is produced in the coiled wire, which attracts the compass needle.

• Because the battery produced a electric field.

• Because the compass is pointing north

What would happen if you took one end of the wire off the battery?

• The nail will be a magnet.

• The nail would no longer be a magnet

• Nothing will happen

• The nail will heats up.

Which part of the electromagnets turned into a magnet when electricity flows through a coiled wire?

• Battery

• Copper wire

• Iron Nail

• Bulb

Tags

NGSS.HS-PS2-5

Bob made an electromagnet but it was very weak. How can he make it stronger?

• take away the battery

• wrap the wire more loosely

• add additional coils

• use less coils

In an electric motor, the coil of the rotor turns into an electromagnet when ...

• the rotor rotates inside the stator

• electric current flows through the coil

• the rotor is turned by the axle

• the commutator is switched on

The commutator is

• The spring-loaded connections that keep contact with the stator

• the device that causes the current to change direction

• the magnets that cause the electromagnet to attract and repulse

• the coil that is also known as the armature

The greater the number of windings (the number of times it is wrapped around) in an electromagnet's coil

• the stronger the magnet is

• the less the magnet will pick up

• the more current it takes to create the electromagnet

• the slower the compass needle moves to the wire

Which of the following will produce the strongest electromagnet?

• A coil of 20 turns of wire

• A coil of 20 turns of wire

• A coil of 30 turns of wire

• A coil of 40 turns of wire

In an electric motor, the energy transformation changes from __________ energy & becomes ___________ energy.

• electrical and becomes chemical

• mechanical and becomes electrical

• electrical and becomes mechanical

• mechanical and becomes chemical