1. What is the main optical element of a refractingtelescope? AA curvedmirror BA
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Question
1. What is the main optical element of a refractingtelescope?AA curvedmirror
BA plane (flat)mirror
CA prism
DA lens 2. A department store sells an "astronomical telescope" with anobjective lens of 30 cm focal length and an eyepiece lens of focallength 5 mm. What is the magnifying power of thistelescope?
A150x
B6x
C15x
D60x 3. The best Earth-based sites for modern large astronomicaltelescopes, in order to reduce the effects of bad seeing uponastronomical images, are
Aon the tops of highmountains, above a large fraction of the disturbingatmosphere.
Bnear to large cities,where the warm air from human activity serves to stabilize theoverlying atmosphere.
Cat sea level, where theair is less turbulent.
Don the down-wind side ofmountain ranges, where smooth airflow produces clear air and stableimages. 4. The major cause of blurring and unsharp images of objectsobserved through very large telescopes, at the extreme limit ofmagnification, is
Athe poor opticalpolish achievable on large mirrors.
Bthe clumsiness of thetelescope operator.
Cthe poor trackingcapabilities of modern telescopes.
Dair turbulence in theEarth's atmosphere. 5. Astronomy from space vehicles is particularly usefulbecause
Athe telescope is in agravity-free state, the mirror is not distorted by gravitationalstress, and can produce sharper images.
Bthe telescope is above theEarth's absorbing and distorting atmosphere and can measureradiation over a very wide wavelength range.
Cthe telescope movessmoothly in a constant orbit, and can produce sharpphotographs.
Dthe telescope is in aclean, dust-free environment and scattered light is muchreduced. 6. Which is the correct order of the types of electromagneticradiation, from the smallest to the largest wavelengths?
AX-rays, sound waves,visible light, radio waves, and microwaves.
BGamma rays, X-rays,ultraviolet radiation, visible light, infrared radiation,microwaves, and radio waves.
Cmicrowaves, visible light,ultraviolet radiation, infrared radiation, X-rays, radio waves, andgamma rays.
Dnone of the above. 7. The following types of electromagnetic radiation can penetrateEarth's atmosphere
Acosmic rays, gammarays, and positrons.
Bradio waves, visiblelight, some infrared and ultraviolet.
Ctachyons, gravitationalwaves, sound waves.
Dradio waves, microwaves,x-rays. 8. To a physicist, a blackbody is defined as an objectwhich
Aabsorbs all radiationwhich falls upon it.
Balways appears to beblack, whatever its temperature.
Calways emits the samespectrum of light, whatever its temperature.
Dreflects all radiationwhich falls upon it, never heating up and always appearingblack. 9. When a rod of metal is heated intensely, its predominant colorwill
Achange from bluethrough white, then orange and finally red, when it becomes red-hotat its hottest.
Bbe white, all colors mixedtogether, as the intensity of light increases.
Cremain red, as theintensity of light increases.
Dchange from red, throughorange to white, and then to blue. 10. When a solid body (or a dense gas such as a star) is cooledfrom a temperature of several thousand degrees, the "color" orwavelength of maximum emission of radiation will
Amove initiallytowards the red end of the spectrum, then move back towards theblue end of the spectrum as the intensity of radiation fades andeventually becomes invisible to the eye.
Bmove steadily towards thered end of the spectrum.
Cremain constant, beingdependent only upon the original color of the body.
Dmove steadily towards theblue end of the spectrum. 11. The hot, dense gas existing on the Sun
Aemits energy only atcertain wavelengths, line emission from hydrogen gas, and not atother wavelengths.
Bemits energy at allwavelengths, with a peak at one particular wavelength(color).
Cemits energy with thesame intensity at all wavelengths, the Earth's atmosphere absorbingradiation at both short and long visible wavelengths to produce theobserved spectrum.
Demits energy mostly atthe longest and shortest wavelengths, with a minimum inbetween. 12. When light passes through a prism of glass
Athe different colorsor wavelengths of light are separated in angle by theprism.
Bthe prism adds colors todifferent parts of the broadly scattered beam coming out ofit.
Cthe prism absorbs colorsfrom different parts of the broad beam coming out of the prism,leaving the complementary colors which we see.
Dthe different colors arecaused by multiple reflections in the prism and interferencebetween the resulting beams.
Explanation / Answer
1) The main element of a refracting telescope is a lens 2) M = fe/fo = 30cm/0.5cm =60x 3) On tops of mountains, removes many of the distortionsfrom our atmosphere 4) A)As telescopes get larger, there are more imperfections onthe mirrors and that is why some of the larger ones will have manysmaller mirrors working together. 5) B) for the same reason as number 2 6) B) Gamma... 7) B) radio 8) A) absorbs all radiation 9) D) starts out as red and moves towards blue as it getshotter 10)B) move toward the red 11)B) all wavelength are emitted but more within onewavelength 12) A) the prism refracts colors different amountsRelated Questions
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