ch19-optics-practice-quiz

____ 21. If the earth did not have an atmosphere, the sky would appear ____ during the day.

____ 22. Stars are not visible during the day because:

a.	the scattered light coming from the sky is too bright to be able to see the weaker light from stars
b.	the earth is pointed away from the center of the galaxy
c.	the light from the stars is absorbed and scattered by the atmosphere and does not reach the ground
d.	all of the above

____ 23. Which of the following would be true if the earth did not have an atmosphere?

a.	there would be fewer hours of daylight
b.	the sky would always be black
c.	the stars would be visible in the sky during the day
d.	all of the above

____ 24. The blue color of the sky is due to:

a.	selective scattering of visible light by air molecules
b.	the filtering effect of water vapor in the earth's atmosphere
c.	reflection of sunlight off the earth's oceans
d.	transmission of visible light through the ozone layer in the earth's stratosphere

____ 25. On a foggy night, it is often difficult to see the road when the high beam lights are on because of ____ of light by the fog.

____ 26. What color would the sky be if air molecules selectively scattered only the longest wavelengths of visible light?

____ 27. If the setting sun appears red, you may conclude that:

a.	the sun's surface temperature has cooled somewhat at the end of the day
b.	only the longest waves of visible light are striking your eye
c.	the next day's weather will be stormy
d.	you will not be able to see the moon that night

____ 28. The sky will begin to turn milky white:

a.	when the concentration of ozone begins to reach dangerous levels
b.	when small particles such as dust and salt become suspended in the air
c.	when the relative humidity decreases below about ten percent
d.	on an oppressively hot day of the year

____ 29. Because of atmospheric refraction, a star seen near the earth's horizon is actually:

a.	slightly higher than it appears
b.	slightly lower than it appears
c.	much dimmer than it appears
d.	much further away than it appears

____ 30. The green flash is largely an example of ____ of light by the earth's atmosphere.

____ 31. If the temperature was constant in the lowest 1000 meters of the atmosphere, conditions would be ____ for viewing a mirage.

____ 32. Which of the following are caused by the bending of light through ice crystals?