What sorts of materials serve as moderators in nuclear reactors?
a. water c. graphite
b. boron d. concrete
A, C
You might also like to view...
Star #1 is approaching the Earth with speed v. Star #2 is receding from the Earth with the same speed v. Measurements of the same spectral line from each of the stars show Doppler shifts in frequency. The light from which star will have the larger magnitude shift in frequency?
a. star #1 b. Both stars will have the same shift. c. The value of the speed must be known before an answer can be found. d. star #2
The name given to the point of a planet's orbit that is closest to the Sun is
a. aphelion. b. focus. c. perihelion. d. solstice.
Spring tides occur close to the time of ______________ moon
a. the new b. the first-quarter c. both the new and the full d. the last-quarter
Which of the following represents the shortest distance?
a. One parsec b. One astronomical unit c. One light-year d. One right ascension