Astronomy Test 2 - quiz 1

If one wants to design a device that will detect animals at night by the radiation they give off, even if the night is totally dark, to what wavelength range should the device be made sensitive?

• infrared

• No device can detect objects on a totally dark night.

• visual, like the human eye

• ultraviolet

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NGSS.HS-PS4-5

The value of "maximum wavelength" in the spectrum given off by a heated blackbody depends on the object's

• A. chemical composition

• B. size

• C. temperature

• D. color

The total amount of radiation emitted by a heated blackbody depends on its temperature and

• its chemical composition

• how much volume it has

• how much surface area it has

• its color

To a physicist, a blackbody is defined as an object that

• always appears to be black, whatever its temperature

• absorbs all radiation that falls on it

• always emits the same spectrum of light, whatever its temperature

An ideal blackbody in physics and astronomy is an object that

• absorbs and emits electromagnetic radiation at all wavelengths

• does not emit or absorb any electromagnetic radiation

• absorbs all electromagnetic radiation but emits none

• emits only infrared light and hence appears black to the eye

Tags

NGSS.HS-PS4-3

When a rod of metal is heated intensely, its predominant color will

• remain red as the intensity of light increases

• change from red through orange to white and then to blue

• change from blue through white, then orange, and finally red

• be white, all colors mixed together, as the intensity increases

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NGSS.HS-PS4-3

The Doppler effect is the

• A. splitting of spectral lines into two or more wavelengths because the source of the light is in a strong magnetic field

• B. increase in the observed wavelength of light if the light source is moving toward you

• C. increase in the observed wavelength of light if the source of light is moving away from you

• D. change in the wavelength of peak emission of light when the source temperature changes

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NGSS.HS-PS4-1

An object is observed to show no Doppler shift. Which of the following cannot describe its motion?

• The object has only a proper motion

• The object has only a radial motion

• The object has only a transverse motion

• The object is stationary

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NGSS.HS-PS4-3

Spectral lines are of particular importance in astronomy because.

• only stars produce bright line spectra

• each different element has a characteristic line spectrum

• they are the only light bright enough to be seen over long distances

• they can be observed through a diffraction grating.

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NGSS.HS-ESS1-2

According to Kirchhoff's laws, the continuous spectrum of light from a hot star, after passing through a cool gas cloud.

• is unaffected because atoms in the gas cloud are too cool to absorb or emit energy

• is enhanced at infrared wavelengths by a continuous spectrum emitted by the cool gas

• contains additional emission lines from energy emitted by the atoms of the cool gas

• shows absorption features where light has been absorbed by the atoms of the cool gas.

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NGSS.HS-PS4-4