What change in the Sun during the solar system's history is thought to be important to understanding the climates of Venus, Earth, and Mars?
A) a gradual brightening with time
B) a gradual dimming with time
C) a gradual weakening of the solar wind with time
D) a gradual reduction in the amount of ultraviolet and x-ray radiation coming from the Sun
A) a gradual brightening with time
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Refracting Telescope: The objective lens of a refracting astronomical telescope has a focal length of 60 cm, and the eyepiece has a focal length of 2.0 cm. How far apart should the lenses be placed in order to form a final image at infinity?
A. 44 cm B. 58 cm C. 76 cm D. 60 cm E. 62 cm
If heat is flowing from a table to a block of ice moving across the table, which of the following must be true?
a. The table is rough and there is friction between the table and ice. b. The ice is cooler than the table. c. The ice is changing phase. d. All three are possible, but none is absolutely necessary.
The area under a curve in a velocity versus time graph gives
A) acceleration. B) velocity. C) displacement. D) position.
A spherical mirror has a radius of curvature of 22 cm. If the mirror is concave, its focal length is
A) -11 cm. B) -22 cm. C) 11 cm. D) -44 cm. E) 22 cm.