5: Radiation and Spectra

Question 1

general term for waves (including light waves) that emit outward from a source

Answer 1

radiation

Question 2

in physics, describes the action of forces that one object exerts on other distant objects

Answer 2

field

Question 3

nonexistent substance said to fill all of space, proposed by nineteenth-century scientists to explain movement of electromagnetic waves

Answer 3

aether

Question 4

number of cycles in a wave per second

Answer 4

hertz (Hz)

Question 5

a series or pattern of dark lines superimposed on a continuous spectrum

Answer 5

absorption spectrum

Question 6

an idealized object that absorbs all electromagnetic energy that falls onto it

Answer 6

blackbody

Question 7

a spectrum of light composed of radiation of a continuous range of wavelengths or colors, rather than only certain discrete wavelengths

Answer 7

continuous spectrum

Question 8

separation of different wavelengths of white light through refraction of different amounts

Answer 8

dispersion

Question 9

the apparent change in wavelength or frequency of the radiation from a source due to its relative motion away from or toward the observer

Answer 9

Doppler effect

Question 10

radiation consisting of waves propagated through regularly varying electric and magnetic fields and traveling at the speed of light

Answer 10

electromagnetic radiation

Question 11

the whole array or family of electromagnetic waves, from radio to gamma rays

Answer 11

electromagnetic spectrum

Question 12

a series or pattern of bright lines superimposed on a continuous spectrum

Answer 12

emission spectrum

Question 13

the amount of energy passing through a unit area (for example, 1 square meter) per second - watts per square meter

Answer 13

energy flux

Question 14

a particular amount of energy possessed by an atom or ion above the energy it possesses in its least energetic state; also used to refer to the states of energy an electron can have in an atom

Answer 14

energy level

Question 15

the process of giving an atom or an ion an amount of energy greater than it has in its lowest energy (ground) state

Answer 15

excitation

Question 16

the number of waves that cross a given point per unit time (in radiation)

Answer 16

frequency

Question 17

photons (of electromagnetic radiation) of energy with wavelengths no longer than 0.01 nanometer; the most energetic form of electromagnetic radiation

Answer 17

gamma rays

Question 18

the lowest energy state of an atom

Answer 18

ground state

Question 19

electromagnetic radiation of wavelength 103–106 nanometers; longer than the longest (red) wavelengths that can be perceived by the eye, but shorter than radio wavelengths

Answer 19

infrared

Question 20

(for light) the amount of energy (light) flowing through a given area in a given time decreases in proportion to the square of the distance from the source of energy or light

Answer 20

inverse square law

Question 21

an atom that has become electrically charged by the addition or loss of one or more electrons

Answer 21

ion

Question 22

the process by which an atom gains or loses electrons

Answer 22

ionization

Question 23

any of two or more forms of the same element whose atoms have the same number of protons but different numbers of neutrons

Answer 23

isotope

Question 24

electromagnetic radiation of wavelengths from 1 millimeter to 1 meter; longer than infrared but shorter than radio waves

Answer 24

microwave

Question 25

the massive part of an atom, composed mostly of protons and neutrons, and about which the electrons revolve

Answer 25

nucleus (of an atom)

Question 26

a discrete unit (or “packet”) of electromagnetic energy

Answer 26

photon

Question 27

motion toward or away from the observer; the component of relative velocity that lies in the line of sight

Answer 27

radial velocity

Question 28

all electromagnetic waves longer than microwaves, including radar waves and AM radio waves

Answer 28

radio waves

Question 29

an instrument for obtaining a spectrum; in astronomy, usually attached to a telescope to record the spectrum of a star, galaxy, or other astronomical object

Answer 29

spectrometer

Question 30

a formula from which the rate at which a blackbody radiates energy can be computed; the total rate of energy emission from a unit area of a blackbody is proportional to the fourth power of its absolute temperature: F = σT4

Answer 30

Stefan-Boltzmann law

Question 31

electromagnetic radiation of wavelengths 10 to 400 nanometers; shorter than the shortest visible wavelengths

Answer 31

ultraviolet

Question 32

electromagnetic radiation with wavelengths of roughly 400–700 nanometers; visible to the human eye

Answer 32

visible light

Question 33

the distance from crest to crest or trough to trough in a wave

Answer 33

wavelength

Question 34

formula that relates the temperature of a blackbody to the wavelength at which it emits the greatest intensity of radiation

Answer 34

Wien’s law

Question 35

electromagnetic radiation with wavelengths between 0.01 nanometer and 20 nanometers; intermediate between those of ultraviolet radiation and gamma rays

Answer 35

X-rays