The focal length of a thin lens is 40 mm and its aperture diameter is 10 mm. What is the f-number of this lens?
A) f/4.0
B) f/2.0
C) f/5.6
D) f/0.30
E) f/0.40
A
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When you are scuba diving, the pressure on your face plate
A) is independent of both depth and orientation. B) will be greatest when you are facing downward. C) depends only on your depth, and not on how you are oriented. D) will be greatest when you are facing upward.
An unusual lightning strike has a vertical portion with a current of ?400 A downwards. The Earth's magnetic field at that location is parallel to the ground and has a magnitude of 30 ?T. In N, the force exerted by the Earth's magnetic field on the 25 m-long current is
a. 0. b. 0.012 N, East. c. 0.012 N, West. d. 0.30 N, West. e. 300 N, East.
To which portion of the Milky Way are the Magellanic Clouds most similar? Why?
What will be an ideal response?
If a source of sound is traveling toward you, the speed of the sound waves reaching you is _______________ the speed the sound waves would have had if the source were stationary
a. faster than b. slower than c. the same as