Doubling the f-number of a camera lens will change the light intensity admitted to the film by what factor?
a. 1/4
c. 1/2
b. 4
d. 2
A
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The mass in the figure slides on a frictionless surface. If m = 2 kg, k1 = 800 N/m and k2 = 500 N/m, the frequency of oscillation (in Hz) is approximately
?
?
a.
6.
b.
2.
c.
4.
d.
8.
e.
10.
The greenhouse effect occurs because carbon dioxide is opaque to infrared radiation
Indicate whether the statement is true or false
Which of the following best explains why nuclear fusion requires bringing nuclei extremely close together?
A) Nuclei normally repel because they are all positively charged and can be made to stick only when brought close enough for the strong force to take hold. B) Nuclei are attracted to each other by the electromagnetic force, but this force is only strong enough to make nuclei stick when they are close together. C) Nuclei have to be hot to fuse, and the only way to get them hot is to bring them close together. D) Fusion can proceed only by the proton—proton chain, and therefore requires that protons come close enough together to be linked up into a chain.
If we could put all the asteroids in the asteroid belt together, their total mass would be
A) much less than the mass of Mercury. B) about the mass of Jupiter. C) about the mass of Earth. D) greater than the mass of Earth but less than the mass of Neptune.