Electromagnetism I

A magnetic field is only produced around wire when there is a _________ through it.

A long coil of wire that is used to create a magnetic field is called…

• A Coil

• A Solenoid

• A Motor

• A Dynamo

Which of the following will NOT increase the speed of a motor? Choose all that apply.

• Increasing the current in the coil

• Flipping the magnetic poles around

• Reversing the current

• Adding more turns of wire in the coil.

• Using stronger permanent magnets

When using the Left Hand Rule. What does your THUMB represent?

• Direction of Current

• Direction of Magnetic Field

• Direction of Force

When using the Left Hand Rule. What does your FIRST (Index / Pointing) finger represent?

• Direction of Current

• Direction of Magnetic Field

• Direction of Force

When using the Left Hand Rule. What does your MIDDLE finger represent?

• Direction of Current from positive to negative

• Direction of Magnetic Field

• Direction of Force

• Direction of current from negative to positive

Which of the following is NOT a use of an electromagnet?

• A motor

• A relay

• A refrigerator door

• An Alarm Bell

A straight wire has a current that travels into your screen. What will its magnetic field look like?

• Concentric circles, pointing clockwise

• Uniform Magnetic Field

• Like a Bar Magnet

• Concentric circles, pointing anticlockwise

In a uniform magnetic field, the field lines are…

• Parallel and equally spaced

• Like a Bar Magnet

• Parallel and getting further apart

• Parallel and getting closer together

The split ring commutator is used for what purpose in a motor?

• To make it spin faster by increasing the strength of the magnetic field

• To keep it spinning by flipping the current in the coil every half a turn

• To flip the current every full turn

• To generate an alternating current