1. What is the main optical element of a refracting telescope?
A A curvedmirror
B A plane (flat)mirror
C A prism
D A 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 this telescope?
A 150x
B 6x
C 15x
D 60x
3. The best Earth-based sites for modern large astronomicaltelescopes, in order to reduce the effects of bad seeing uponastronomical images, are
A on the tops of highmountains, above a large fraction of the disturbingatmosphere.
B near to large cities,where the warm air from human activity serves to stabilize theoverlying atmosphere.
C at sea level, where theair is less turbulent.
D on 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 of magnification, is
A the poor opticalpolish achievable on large mirrors.
B the clumsiness of thetelescope operator.
C the poor trackingcapabilities of modern telescopes.
D air turbulence in theEarth's atmosphere.
5. Astronomy from space vehicles is particularly usefulbecause
A the telescope is in agravity-free state, the mirror is not distorted by gravitationalstress, and can produce sharper images.
B the telescope is above theEarth's absorbing and distorting atmosphere and can measureradiation over a very wide wavelength range.
C the telescope movessmoothly in a constant orbit, and can produce sharpphotographs.
D the 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?
A X-rays, sound waves,visible light, radio waves, and microwaves.
B Gamma rays, X-rays,ultraviolet radiation, visible light, infrared radiation,microwaves, and radio waves.
C microwaves, visible light,ultraviolet radiation, infrared radiation, X-rays, radio waves, andgamma rays.
D none of the above.
7. The following types of electromagnetic radiation can penetrateEarth's atmosphere
A cosmic rays, gammarays, and positrons.
B radio waves, visiblelight, some infrared and ultraviolet.
C tachyons, gravitationalwaves, sound waves.
D radio waves, microwaves,x-rays.
8. To a physicist, a blackbody is defined as an objectwhich
A absorbs all radiationwhich falls upon it.
B always appears to beblack, whatever its temperature.
C always emits the samespectrum of light, whatever its temperature.
D reflects all radiationwhich falls upon it, never heating up and always appearingblack.
9. When a rod of metal is heated intensely, its predominant colorwill
A change from bluethrough white, then orange and finally red, when it becomes red-hotat its hottest.
B be white, all colors mixedtogether, as the intensity of light increases.
C remain red, as theintensity of light increases.
D change 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" or wavelength of maximum emission of radiation will
A move 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.
B move steadily towards thered end of the spectrum.
C remain constant, beingdependent only upon the original color of the body.
D move steadily towards theblue end of the spectrum.
11. The hot, dense gas existing on the Sun
A emits energy only atcertain wavelengths, line emission from hydrogen gas, and not atother wavelengths.
B emits energy at allwavelengths, with a peak at one particular wavelength(color).
C emits energy with thesame intensity at all wavelengths, the Earth's atmosphere absorbingradiation at both short and long visible wavelengths to produce theobserved spectrum.
D emits energy mostly atthe longest and shortest wavelengths, with a minimum inbetween.
12. When light passes through a prism of glass
A the different colorsor wavelengths of light are separated in angle by theprism.
B the prism adds colors todifferent parts of the broadly scattered beam coming out ofit.
C the prism absorbs colorsfrom different parts of the broad beam coming out of the prism,leaving the complementary colors which we see.
D the different colors arecaused by multiple reflections in the prism and interferencebetween the resulting beams.