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24 Cards in this Set

  • Front
  • Back
an object that absorbs all electromagnetic radiation that falls onto it. No radiation passes through it and none is reflected.
Blackbody curves
Curves that shows the intensity of radiation over a wide range of wavelengths emitted by a blackbody at a particular temperature.
Wein's law
The dominant wavelength of radiation emitted by a blackbody is inversely proportional to its temperature.

Who's law is this?
What color are hot stars?
What color are cool stars?
Stefen-boltzman law
An object emits energy per unit area at a rate proportional to the 4th power of its temperature in kelvins.
T or F

Each star has a different spectrum.
Absorption spectrum
fraction of incident electromagnetic radiation absorbed by the material over a range of frequencies.

opposite of emission spectrum
Emission spectrum
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).
A device for photographing a spectrum
Planck's law
This person's law is about the relationship btwn the energy of a photon and its wavelength. Whose is it?
Doppler shift
how wavelengths change when they are moving
coming toward us and is shorter

what shift?
moving away or toward something

what shift?
The doppler shift only works when moving ______ or _______ something.
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.
_________ 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.
______________ law relates the temperature of a blackbody to the rate at which it radiates energy.
the study of electromagnetic spectra - provides important information about the chemical composition of the remot astronomical objects.
___________ 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.
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.
How hot is a "red hot" object?
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.
What color is the Sun?
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.
How can we determine the age of space debris found on Earth?
The equation describing the ________ effect states that the size of a wavelength shift is proportional to the ________ velocity btwn the light source and the _________.