Current searches for extraterrestrial intelligence use radio telescopes at wavelengths
a. which must be shorter than the local wavelengths emitted by Earth's atmosphere.
b. which must be longer than the radio wavelength ‘noise' naturally emitted by our galaxy.
c. which must be longer than the local wavelengths emitted by Earth's atmosphere and which must be shorter than the radio wavelength ‘noise' naturally emitted by our galaxy.
d. Wrong! Visual light wavelengths are used because radio waves are blocked by dust between the stars.
c
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Describe one major accomplishment for each of the following people: Copernicus, Tycho Brahe, Kepler, and Galileo
What will be an ideal response?
Which of the following is not a derived quantity?
a. Volume b. Speed c. Mass d. Density
Which statement about a single thin lens is correct?
A) A converging lens always produces a real inverted image. B) A diverging lens always produces a virtual inverted image. C) A converging lens sometimes produces a real upright image. D) A diverging lens always produces a virtual upright image. E) A diverging lens produces a virtual upright image only if the object is located between the lens and its focal point.
Visible light with wavelengths at the long-wavelength end (l= 700 nm) appears as which color?
a. red b. orange c. yellow d. green e. blue