Review of Electromagnetism

All substances continuously ___________radiant energy in a mixture of _______________.

All substances continuously _emit_____________radiant energy in a mixture of _frequencies and wavelengths__________________.

Sources with higher _____________ emit radiation with shorter wavelengths.

Sources with higher temperatures emit radiation with shorter wavelengths.

Best colors for clothes to stay warm on a dark night with a clear sky are ________________________.

Best colors for clothes to stay warm on a dark night with a clear sky are ________light______________.

When radiant energy encounters an object, the object partly ____________ and partly reflects the energy.

When radiant energy encounters an object, the object partly absorbs and partly reflects the energy.

Best colors for clothes to stay warm on a sunny and cold day are _________________.

Best colors for clothes to stay warm on a sunny and cold day are ________dark_________.

We can’t see infrared light or ultraviolet light because:

We can’t see infrared light or ultraviolet light because: they are not visible light.

Poor __________ are also poor emitters

Poor absorbers are also poor emitters

Name a color that is hotter than white.

Blue, Indigo, and Violet

When an object emits radiant energy, its internal energy is ___________.

When an object emits radiant energy, its internal energy is reduced.

If the temperature of an object is cut in half, then the frequency of the emitted radiation will be ________________.

If the temperature of an object is cut in half, then the frequency of the emitted radiation will be cut in half.

Absorption and reflection are __________ processes.

Absorption and reflection are opposite processes.

Two identical dark metal plates are the same temperature. One side of one plate is covered with aluminum. Which plate radiates more energy? Why?

Two identical dark metal plates are the same temperature. One side of one plate is covered with aluminum. Which plate radiates more energy? The plate without aluminum foil radiates more energy Why? Aluminum reflects the energy from the plate back into the plate.

You split white light with a prism. Which color bends the most?

Violet

What has more energy, infrared light or ultraviolet light?

Ultraviolet

Why does infrared light heat our body and ordinary objects more than ultraviolet light?

The natural frequency of our bodies & objects more closely match IR light.

What creates electromagnetic waves?

Accelerating electric charges

The nearly parallel lines produced when iron filings are sprinkled near a magnet let us see what?

The nearly parallel lines produced when iron filings are sprinkled near a magnet let us see what? Magnetic field lines

This the definition of what? Oscillating electric and magnetic fields that regenerate each other.

This the definition of what? Oscillating electric and magnetic fields that regenerate each other. Definition of Electromagnetic Wave

What do we call the space around a magnet in which a magnetic force is exerted.

Magnetic field

What two waves make up an electromagnetic wave?

Electric and Magnetic

Where do magnetic field lines begin and end?

Poles of the magnet

If a magnetic field is changing, what does that cause to happen?

A changing electric field

What surrounds electric current flowing in a wire?

A magnetic field

[gamma waves, infrared waves, light, microwaves, radio waves, ultraviolet waves, x-rays] Put these waves in order of decreasing wavelength.

Radio, microwaves, infrared, light, ultraviolet, x rays, gamma rays

What magnetic poles attract?

N-S and S-N (opposite)

How can you use a bar magnet to determine the magnetic polarity of the Earth’s south pole?

Move the south pole of the bar magnet toward the south pointing compass needle. If the needle moves away from the south pole of the block magnet, then Earth’s south pole has a Northern magnetic polarity.

If you are able to stack some magnets so that they levitate (float above the magnets below), what must be true about the polarities on adjacent faces?

Adjacent faces must have the same polarity. N N S S N S

The plastic strip was rubbed with fur, and the metal block started with no net charge. Draw the charges on the plastic strip and inside the metal block after the plastic strip is brought close to the metal block. Plastic Strip Metal Block

The plastic strip was rubbed with fur, and the metal block started with no net charge. Draw the charges on the plastic strip and inside the metal block after the plastic strip is brought close to the metal block. Plastic Strip Metal Block

If the floor that the metal block is on has no friction, in which direction would it move? Plastic Strip Metal Block

If the floor that the metal block is on has no friction, in which direction would it move? The block would move to the left because it is attracted to the plastic strip. Plastic Strip Metal Block

Why would the charges distribute like they are shown? Plastic Strip Metal Block

Why would the charges distribute like they are shown? The electrons in the metal block are repelled by the electrons on the plastic strip, and the positive charges in the metal block are attracted to the plastic strip. Plastic Strip Metal Block

Which of the following statements do not belong with the other statements? lines of iron filings begin and end here. Field lines are closest here Field strength is greatest here A charge can sit still here.

Which of the following statements do not belong with the other statements? lines of iron filings begin and end here. Field lines are closest here Field strength is greatest here A charge can sit still here.  Not true, it will be pushed by the magnetic field

In order, what are then names of the atomic particles that carry the following charges: Negative: Positive: Neutral:

In order, what are then names of the atomic particles that carry the following charges: Negative:Electron Positive:Proton Neutral:Neutron

Name two ways that charges can be transferred from one object to another.

Friction and Contact

Why did the motor that we built change direction when the magnet was flipped?

The coil & battery make a magnetic field that pushes on one side of the coil and pulls on the other side of the coil. By flipping the block magnet, the forces are reversed and the coil rotation is also reversed.

What determines how much electricity is induced into wire loops moving through a magnetic field?

The number of field lines crossed. The speed of the motion. The number of loops

How does a negatively charged object become attracted to an insulator?

Molecules in the insulator must rotate so that a positive charge is nearest to the object.

What do we call the process of the molecules in the insulator rotating to be attracted to a charged object?

Electrical polarization

Why do metal dishes lift off from the Van de Graff generator, but the plastic dishes don’t?

The metal dishes can accumulate charge on their surface and inside them. Plastic dishes can only accumulate charges on their surface. Only the metal dishes have enough repulsion to overcome gravity.