A contact lens is made of plastic with an index of refraction of 1.50 . The lens has an outer radius of curvature of +2.0 cm and an inner radius of curvature of +2.5 cm. What are the focal length and the power of the lens?
+20 cm, +5.0 diopters
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You are driving along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind at constant speed and you perceive the frequency as
You are relieved that he is in pursuit of a different driver when he continues past you, but now you perceive the frequency as What is the speed of the police car? The speed of sound in air is A) 40.1 m/s B) 41.7 m/s C) 39.2 m/s D) 30 m/s E) 38.4 m/s
An angle of 1 arcsecond is
A) about the width of your fist held at arm's length. B) about the width of a finger held at arm's length. C) less than the thickness of a human hair held at arm's length. D) slightly more than the width of a basketball held at arm's length.
A spaceship traveling very fast relative to you fires a stream of photons at speed c away from you. You measure the photons' speed to be
A) less than c. B) more than c. C) equal to c.
An observer traveling with speed 0.5c moves directly toward a beacon emitting photons with speed c in her direction. The observer measure the speed approaching photons to be
(a) 0.25c (b) 0.5c (c) c (d) 1.5c