Chapter 14 Electromagnetic Energy

Question 1

examples of mechanical waves (i.e., waves that move matter)

Answer 1

sound waves, water waves, seismic waves

Question 2

EM (electromagnetic) spectrum

Answer 2

a frequency continuum of waves that (a) transfers energy, (b) can be transmitted in a vacuum (aka matterless space)

Question 3

waves in the EM spectrum

Answer 3

visible light waves

radio waves

microwaves

x-rays

infrared waves

ultraviolet light

Question 4

Sir Isaac Newton, 1600s, dispersed sunlight into a rainbow of colors using __.

Answer 4

prisms

Question 5

Electromagnetic (EM) force

Answer 5

the relationship of the electrostatic force to the magnetic force.

Question 6

How electric fields, magnetic fields, and light interact

Answer 6

in a wave-like fashion, with light moving as a wave disturbance in the electric/magnetic fields.

Question 7

How light moves

Answer 7

light moves as waves,

by oscillating

in magnetic & electric fields that are perpendicular to each other

Question 8

mathematical speed of light (c)

[c is the constant for the speed of light in a vacuum]

Answer 8

c in a vacuum is 299 million m/s

(aka 3.00 x 10⁸ m/s)

(going through matter can change the speed)

Question 9

measurable properties of electromagnetic waves

Answer 9

frequency

wavelength

Question 10

mathematical equation for an EM wave

Answer 10

constant = frequency x wavelength

[c = f x upside down Y]

Question 11

Light’s “wave properties” cause it to refract

which looks like

Answer 11

a bending of the light or image

Question 12

Light travels in a wave bundle called a

Answer 12

photon.

(All EM energy is transported as photons.)

Question 13

Ways photons can act:

Answer 13

like waves (refracting, diffracting, and interfering)

& like particles (having momentum, moving in straight lines, and affecting individual atoms)

Question 14

Formula for the energy of a photon

Answer 14

Photon’s energy =

Planck’s constant x the frequency of a photon’s EM waves.

Question 15

Aspects of radio waves

Answer 15

They carry radio & TV signals and can follow the curvature of the earth.

They are at the low end of the EM spectrum.

They are divided into frequencies and includes the VHF band.

Produced by the acceleration of electrons by a magnetic or electric field.

Question 16

Describe aspects of microwaves

Answer 16

They span the upper end of the radio-frequency band [e.g., UHF (ultra-high freq) for cell phones].

Produced, like radio waves, by the acceleration of electrons by a magnetic or electric field.

Can only travel in a line of sight (straight line).

Question 17

Aspects of InfraRed (IR) waves

Answer 17

Higher frequency than microwaves.

All matter produces it (above absolute zero) because electrons are moving.

The lowest EM frequency visible to the eye.

Produced mostly by the thermal vibration of atoms and molecules.

Question 18

Aspects of visible light

Answer 18

includes all the EM frequencies humans can see.

emitted when electrons lose energy within the atom (not by the physical movement of electrons).

Question 19

Ultraviolet rays

Answer 19

Frequencies are beyond those of deep violet visible light.

Frequencies too high for human eye to detect.

Called “black light” because it can’t be seen.

AKA UV rays or UV radiation.

Produced like visible light waves, but with large energy changes that emit very energetic UV photons.

Question 20

Aspects of XRay waves

Answer 20

created when high-speed electrons strike an atom and slow down rapidly.

Lost kinetic energy of that slowing is converted into high-energy xray photons.

Can penetrate matter.

Question 21

Gamma Rays

Answer 21

at the highest frequency of the EM spectrum.

made by changes in atomic nuclei, not from colliding electrons.

have the shortest known wavelengths.

have the highest energy per photon.

the can destroy chemical bonds and change elements into a different kind.

Radioactive elements release gamma rays.