An object is placed 60 cm in front of a mirror and the image is upright and 1?4 the size of the object. What is the focal length of the mirror?
A. -12 cm
B. -20 cm
C. -45 cm
D. -75 cm
E. some positive value not given
B. -20 cm
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The impulse experienced by a body is equivalent to its change in:
a. velocity. b. kinetic energy. c. momentum. d. None of the above choices are valid.
Technology is mainly
A) a body of scientific knowledge. B) a tool of science. C) what is wrong with the world. D) a solution to all of mankind's problems.
An observer in the Southern Hemisphere takes a time exposure photograph of the night sky. If the illustration below depicts the photograph taken by the observer, which direction was the camera pointing
a.
straight north
b.
straight east
c.
straight south
d.
straight west
e.
straight up, directly overhead
Two thin layers of material with different indices of refraction are coated on a glass plate. The outer first material has n1 = 1.461, the inner second material has n2 = 1.544, and the glass has nglass = 1.62 . If light is incident from air on the first layer, what is the phase change for light that reflects from the glass?
a. 180° b. 0° c. 360° d. 540° e. 720°