Electromagnetic Induction

Electromagnetic induction is change in ___________________. 

• surface area
• magnetic poles
• magnetic flux

Voltage can be induced in a wire by

• a. moving the wire near a magnet.
• b. moving a magnet near the wire.
• c. changing the current in a nearby wire.
• d. all of these

What would happen if I move a bar magnet in and out of a coil of copper wire?

• Electric current would disappear 
• The magnet would explode 
• Electric current will flow through the wire
• It would produce a gravitational field

A magnet is moved in and out of a coil of wire connected to a high-resistance voltmeter. If the number of coils doubles, the induced voltage 

• quadruples
• doubles
• is the same
• halves

___ Law says that the Induced current is proportional to the change of magnetic flux 

• Lenz'
• Faraday's
• Ampere's

Which description best applies to Lenz's Law?

• An induced current occurs when a magnet passes through a tube.

• When a change in magnetic field occurs to a coil the direction of current goes in the in the other direction to this change.

• The direction of an induced current is such to align with the change that created it.

• A magnet is a tube is always slowed by its magnetic field.

Which action will increase the deflection of the galvanometer pointer?

• The magnetic pole is reversed

• The number of turns of coils is increased

• The coil is made from insulated wire

• The magnet is slowly pushed into the coil

___ Law says that a current produced by an induced emf moves in a direction so that its magnetic field opposes the original change in flux

• Lenz'
• Faraday's
• Ampere's

If you wrap more coils around an electromagnet, it will become...

• brighter
• stronger
• weaker
• invisible

The unit of magnetic flux is the

• Henry
• Tesla
• Faraday
• Weber