The motor effect

What happens when a current flows through a wire in a magnetic field?

• The wire jumps due to a force.

• The wire becomes hot.

• The wire becomes an electromagnet.

• The wire changes its color.

What do field lines from a magnet represent?

• The direction that a compass would point - from North to South

• The direction of electric current

• The shape of the magnet

• The direction that a compass would point - from South to North

What is the role of electromagnets in electric motors?

• To cool down the motor

• To generate magnetic fields

• To increase the weight of the motor

• To reduce the electric current

According to Fleming's left-hand rule, what does the thumb represent?

• Direction of the electric current

• The power of the magnet

• Direction of the magnetic field

• Motion or thrust

What is necessary for the projectile in a railgun to work?

• It must be made of plastic.

• It needs to conduct electricity.

• It should be lightweight.

• It must be magnetic.

How can the force on a wire in a magnetic field be increased?

• By using a weaker magnet

• By using a smaller wire

• By decreasing the current

• By using more current or a stronger magnet

What is the main function of the commutator in an electric motor?

• To connect the motor to the power supply

• To reverse the direction of the current

• To generate electricity

• To reduce friction

What does the coil of wire in an electric motor become when a current flows through it?

• A resistor

• An electromagnet

• A conductor

• A permanent magnet

What is the purpose of brushes in an electric motor?

• To increase the speed of the motor

• To clean the motor

• To cool down the motor

• To ensure the current flows into the coils

What makes the coil in an electric motor continue to rotate?

• The constant speed of the motor

• The temperature of the motor

• The changing direction of the current

• The shape of the motor