Magnetism and Electromagnetism

When we bring the magnets closer together when the forces are repulsive, we observe that

• the magnets stick together

• the poles of the magnets switch

• the magnets move away from each other

• the train car slows down

When the opposite poles of two magnets are held further apart, the magnets will ​ (a)   ​ because the ​ (b)   stored in the magnetic field transfers into ​ (c)  

• attract
• potential energy
• kinetic energy

When we increase the amplitude of an electric current, the electromagnet

• switches directions

• has a stronger current

• becomes weaker when in a repel situation

• can propel a train

Reorder the following to show the steps which occur when a computer produces different vibrations and different sounds.

• change in the orientation of the battery

• change in the poles of the electromagnet

• change in the vibration of the speaker and change in the sounds we hear

• change in the direction of forces in the magnetic field

• change in the direction of the current

When the electric current is rapidly switched back and forth in a coil of wire inside a speaker,

• the sound gets louder and softer

• The frequency of the sound goes up and down

• the speaker vibrates and creates sound

• the membrane will stretch

When we switch the direction of the electric current,

• the size of the magnetic field increases

• the sound of the speaker gets softer

• the magnet will repel

• the poles of the electromagnet are reversed

When we increase the amount of electricity in a wire

• the magnetic field will increase

• the magnet will attract

• the electrons will heat up

• the car battery will last longer

What causes the speaker membrane to change directions?

• the battery inside the speaker is moving back and forth

• the current in the electromagnet changes directions

• a song with high amplitude

• a song with high frequency

Match the following

• the speaker gets louder

• the effect of changing the direction of electricity going into a speaker

• the poles of the electromagnet flip

• the effect of changing the amount of electricity going into a speaker

• the sound stops or becomes static

• the effect of losing control over when a speaker's wire sent electricity in different directions