Stars with masses between 0.4 and 4
a. undergo thermonuclear fusion of hydrogen and helium, but never get hot enough to ignite carbon.
b. undergo thermonuclear fusion of hydrogen, but never get hot enough to ignite helium.
c. produce type-I supernovae after they exhaust their nuclear fuels.
d. produce type-II supernovae after they exhaust their nuclear fuels.
e. undergo carbon detonation.
A
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A heavy ball hangs by a string, with a second string attached to its bottom (Figure 1.7 in your text). A quick pull on the bottom string breaks the
A) top string. B) bottom string. C) top or bottom string equally likely. D) none of the above
Momentum and energy from focused laser beams can be used in nuclear fusion. This is because
A. light is not magnetic. B. the wavelength of light is small enough to penetrate each proton. C. light cannot be melted, so its pressure can confine the reaction. D. light can also function as a moderator, like graphite or water in a uranium reactor.
A planet has two identical moons with identical mass. Moon 1 is in a circular orbit of radius r. Moon 2 is in a circular orbit of radius 2r. The magnitude of the gravitational force exerted by the planet on Moon 2 is
1.four times as large as the gravitational force exerted by the planet on Moon 1. 2.twice as large as the gravitational force exerted by the planet on Moon 1. 3.the same as the gravitational force exerted by the planet on Moon 1. 4.half as large as the gravitational force exerted by the planet on Moon 1. 5.one-fourth as large as the gravitational force exerted by the planet on Moon 1.
In an analysis relating Bohr's theory to the de Broglie wavelength of electrons, when an electron moves from the n = 1 level to the n = 3 level, the circumference for its orbit becomes 9 times greater. This occurs because:
a. the wavelength of the electron becomes nine times as long. b. there are triple as many wavelengths, and each wavelength is triple in length. c. there are nine times as many wavelengths in the new orbit. d. the electron is moving nine times as fast.