! 4 ! Astronomy

Front 1

Blackbody

Back 1

an object that absorbs all electromagnetic radiation that falls onto it. No radiation passes through it and none is reflected.

Front 2

Blackbody curves

Back 2

Curves that shows the intensity of radiation over a wide range of wavelengths emitted by a blackbody at a particular temperature.

Front 3

Wein's law

Back 3

The dominant wavelength of radiation emitted by a blackbody is inversely proportional to its temperature.

Who's law is this?

Front 4

blue

Back 4

What color are hot stars?

Front 5

red

Back 5

What color are cool stars?

Front 6

Stefen-boltzman law

Back 6

An object emits energy per unit area at a rate proportional to the 4th power of its temperature in kelvins.

Front 7

True

Back 7

T or F

Each star has a different spectrum.

Front 8

Absorption spectrum

Back 8

fraction of incident electromagnetic radiation absorbed by the material over a range of frequencies.

opposite of emission spectrum

Front 9

Emission spectrum

Back 9

atoms in gas clouds re-emit absorbed light energy at the same wavelength at which they are absorbed.

the relative intensity of electromagnetic radiation of each frequency it emits when it is heated (or more generally when it is excited).

Front 10

Spectrograph

Back 10

A device for photographing a spectrum

Front 11

Planck's law

Back 11

This person's law is about the relationship btwn the energy of a photon and its wavelength. Whose is it?

Front 12

Doppler shift

Back 12

how wavelengths change when they are moving

Front 13

blue-shift

Back 13

coming toward us and is shorter

what shift?

Front 14

red-shift

Back 14

moving away or toward something

what shift?

Front 15

Away
towards

Back 15

The doppler shift only works when moving ______ or _______ something.

Front 16

blackbody
temperature

Back 16

A ________ is a hypothetical object that perfectly absorbs electromagnetic radiation at all wavelengths. The radiation that it emits depends only on its ___________. Stars closely approximate blackbodies.

Front 17

Wien's

Back 17

_________ law states that the dominant wavelength of radiation emitted by a blackbody is inversely proportional to its temperature. The intensities of radiation emitted at various wavelengths by a blackbody at a given temperature are shown as a blackbody.

Front 18

Stefen-boltzmann

Back 18

______________ law relates the temperature of a blackbody to the rate at which it radiates energy.

Front 19

Spectroscopy

Back 19

the study of electromagnetic spectra - provides important information about the chemical composition of the remot astronomical objects.

Front 20

Kirchoff's
Spectral

Back 20

___________ three laws of spectral analysis describe the condition under which absorption lines, emission lines, and a distinctive "fingerprints" for the chemical elements and chemical compounds comprising a light source.

Front 21

Of all objects that glow visibly from heat stored or generated inside them, those that glow red are the coolest. Those that glow violet are the hottest.

Back 21

How hot is a "red hot" object?

Front 22

The Sun emits all wavelengths of electromagnetic radiation. The colors it emits most intensely are in the blue-green part of the spectrum. Since the human eye is less sensitive to blue-green than to yellow and the Earth's atmosphere scatters blue-green wavelengths more readily than longer wavelengths, we see the Sun as yellow.

Back 22

What color is the Sun?

Front 23

We measure how much long-lived radioactive elements, such as 238U, have decayed in the object. Carbon dating is only reliable for things that formed within the past 100,000 years. Itcannot be used for determining the age of debris found on Earth, which was all formed more than 4.5 billion years ago.

Back 23

How can we determine the age of space debris found on Earth?

Front 24

doppler
radial
observer

Back 24

The equation describing the ________ effect states that the size of a wavelength shift is proportional to the ________ velocity btwn the light source and the _________.