Lab Exam 2 Stars And Galaxies

Front 1

Visible light

Back 1

The small range of the electromagnetic spectrum that human eyes perceive as light. The visible spectrum ranges from about 400-700 nm, corresponding to blue through red light.

Front 2

Electromagnetic radiation

Back 2

Another term for light, it transfers energy and information from one place to another.

Front 3

Wave

Back 3

A pattern that repeats itself cyclically in both time and space. These are characterized by the speed at which they move, their frequency, and their wavelength.

Front 4

Period

Back 4

The time needed for an orbiting body to complete one revolution about another body.

Front 5

Wavelength

Back 5

The distance from one wave crest (or trough) to the next, at a given instant in time.

Front 6

Amplitude

Back 6

The maximum deviation of a wave above or below the zero point.

Front 7

Frequency

Back 7

the number of wave crests passing any given point in a unit time.

Front 8

Electrons

Back 8

An elementary particle with a negative electric charge; one of the components of the atom.

Front 9

Protons

Back 9

An elementary particle carrying a positive electric charge. A component of all atomic nuclei. The number of these in the nucleus of an atom dictates what type of atom it is.

Front 10

Electric field

Back 10

A field extending outward in all directions from a charged particle, such as a proton or an electron. This determines the electric force exerted by the particle on all other charged particles in the universe; the strength of these decreases with increasing distance from the charge according to an inverse-square law.

Front 11

Magnetic field

Back 11

A field that accompanies any changing electric field and governs the influence of magnetized objects on one another.

Front 12

Speed of light

Back 12

The fastest possible speed, according to the currently know laws of physics. Electromagnetic radiation exists in the form of waves or photons moving at this speed.

Front 13

Diffraction

Back 13

The ability of waves to bend around corners. This with light establishes its wave nature.

Front 14

Interference

Back 14

The ability of two or more waves to interact in such a way that they either reinforce or cancel each other.

Front 15

Electromagnetic spectrum

Back 15

The complete range of electromagnetic radiation, from radio waves to gamma rays, including thee visible spectrum. All types of electromagnetic radiation are basically the same phenomenon, differing only by wavelength, and all move at the speed of light.

Front 16

Radio waves

Back 16

Electromagnetic radiation with wavelength in the radio part of the spectrum.

Front 17

Infrared radiation

Back 17

is invisible radiant energy, with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz) to 1 mm (300 GHz)[1] (although people can see infrared up to at least 1050 nm in experiments. Most of the thermal radiation emitted by objects near room temperature is infrared.

Front 18

Ultraviolet radiation

Back 18

is electromagnetic radiation with a wavelength shorter than that of visible light but longer than X-rays (from 400 nm to 10 nm in wavelength). Though usually invisible, under some conditions children and young adults can see ultraviolet down to wavelengths of about 310 nm,[1][2] and people with aphakia (missing lens) can also see some UV wavelengths. Near-UV is visible to a number of insects and birds.

Front 19

X-rays

Back 19

Region of the electromagnetic spectrum corresponding to radiation of high frequency and short wavelength, far beyond the visible spectrum.

Front 20

Gamma rays

Back 20

Region of the electromagnetic spectrum, far beyond the visible spectrum, corresponding to radiation of very high frequency and very short wavelength.

Front 21

Temperature

Back 21

A measure of the amount of heat in an object, and an indication of the speed of the particles that comprise it.

Front 22

Doppler effect

Back 22

Any motion-induced change in the observed wavelength (or frequency) of a wave.

Front 23

Blackbody curve

Back 23

The characteristic way in which the intensity of radiation emitted by a hot object depends on frequency. The frequency at which the emitted intensity is highest is an indication of the temperature of the radiating object.

Front 24

Wien’s law

Back 24

Relation between the wavelength at which a blackbody curve peaks and the temperature of the emitter. The peak wavelength is inversely proportional to the temperature, so the hotter the object, the bluer its radiation.

Front 25

Spectroscope

Back 25

An instrument used to view a light source so that it is split into its component colors.

Front 26

Continuous spectrum

Back 26

Spectrum in which the radiation is distributed over all frequencies, not just a few specific frequency ranges. A prime example is the blackbody radiation emitted by a hot, dense body.

Front 27

Emission spectrum

Back 27

the pattern of spectral emission lines produced by an element. Each element has its own unique emission spectrum.

Front 28

Emission lines

Back 28

bright line in a specific location of the spectrum of radiating material, corresponding to a emission of light at a certain frequency. A heated gas in a glass container produces these lines in its spectrum.

Front 29

Absorption lines

Back 29

dark lines in an otherwise continuous bright spectrum, where light within one narrow frequency range has been removed.

Front 30

Absorption spectrum

Back 30

The electromagnetic spectrum, broken by a specific pattern of dark lines or bands, observed when radiation traverses a particular absorbing medium.

Front 31

Kirchhoff’s laws

Back 31

three rules governing the formation of different types of spectra.

Front 32

Spectroscopy

Back 32

The study of the way in which Atoms absorb and emit electromagnetic radiation. This allows astronomers to determine the chemical composition of stars.

Front 33

Atoms

Back 33

building block of matter, composed of positively charged protons and neutrons in the nucleus surrounded by negatively charged electrons.

Front 34

Nucleus

Back 34

dense, central region of an Atom, containing both protons and neutrons, and orbited by one or more electrons. The solid region of ice and dust that composes the central region of the head of a comet. The dense central core of a galaxy.

Front 35

Element

Back 35

matter made up of one particular Atom. The number of protons in the nucleus of the Atom determines which element is represents.

Front 36

Ground state

Back 36

the lowest energy state that an electron can have within an atom.

Front 37

Ionized

Back 37

The state of an Atom or molecule that has lost more of its electrons.

Front 38

Excited states

Back 38

State of an Atom when one of its electrons is in a higher energy orbital in the ground state. Atoms can become excited by absorbing a photon of the specific energy, or by colliding with a nearby Atom.

Front 39

Quantized

Back 39

the fact that light in matter on small scales behave in the discontinuous matter, and manifest themselves in the form of tiny “package” of energy, called Quanta.

Front 40

Photons

Back 40

individual packet of electromagnetic energy that makes of electromagnetic radiation.

Front 41

Photoelectric effect

Back 41

the emission of an electron from a surface when a photon of electromagnetic radiation is it absorbed.

Front 42

Molecules

Back 42

A tightly bound collection of Atoms held together by Atoms’ electromagnetic fields. Molecules, like Atoms, emit and absorb photons at specific wavelengths.