Tritium is radioactive with a half-life of 12.33 years decaying into 3He with low-energy electron emission. If we have a sample of 2.35 × 10^19 tritium atoms, what is its activity in decays/second? (1 year = 3.16 × 10^7 s)
a. 6.64 × 10^7/second
c. 3.69 × 10^8/second
b. 5.35 × 10^9 /second
d. 4.18 × 10^10/second
D
You might also like to view...
In a metal that is not a superconductor, as the temperature increases which of the following is true?
(a) Free electrons are scattered more frequently by structural defects. (b) Free electrons are scattered more frequently thermal vibrations. (c) Free-electron drift velocity is increased because of scattering by vibrating atoms. (d) Free-electron drift velocity is a constant.
Heavily cratered, lower-density regions of the lunar surface are called ________.
A. Tycho B. rilles C. regolith D. maria E. highlands
You discover a binary star system in which one member is a15 solar mass main-sequence star and the other star is a 10 solar mass giant star. How do we believe that a star system such as this might have come to exist?
A) The two stars probably were once separate but became a binary when a close encounter allowed their mutual gravity to pull them together. B) Other than the very low odds of finding a system with two such massive stars, there is nothing surprising about the fact that such systems exist. C) The main-sequence star probably is a pulsating variable star and therefore appears to be less massive than it really is. D) Although both stars probably formed from the same clump of gas, the more massive one must have had its birth slowed so that it became a main-sequence star millions of years later than its less massive companion. E) The giant must once have been the more massive star but transferred some of its mass to its companion.
A modern day device that does not need to have a computer chip built into it is
A. a cell phone. B. a blood pressure meter. C. a hand held calculator. D. an MP3 player.