A magnifying glass has a convex lens of focal length 15 cm. At what distance from a postage stamp should you hold this lens to get a magnification of +2.0?
7.5 cm
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Which of the terrestrial planets has the most difficult time retaining an atmosphere?
a. Mercury b. Venus c. Earth d. Mars
What causes the geological activity seen on some of the inner moons of Jupiter?
a. Constant collisions with space debris provide a power source for geological activity. b. The strong magnetic field of Jupiter heats the surface of the inner moons. c. Tidal friction as a result of being so close Jupiter heats their interiors. d. Solar radiation reflected of Jupiter's surface provides a power source for geological activity.
According to Newtonian physics, an object with no forces acting on it must
A) be accelerated, with an unchanging acceleration. B) either be at rest or have constant velocity. C) eventually come to rest. D) be at rest. E) fall.
Having nothing to do with trigonometry, ________ parallaxes use the width of absorption lines to estimate the star's luminosity and size and distance
A) bolometric B) photometric C) spectroscopic D) holographic E) videometric