Homer says that we can safely use nuclear power because all radioactive nuclei are gone after two half-lives. Marge says that only the decay rate is zero after two half-lives. Which one, if either, is correct, and why?
a. Homer, because half of the nuclei disintegrate in each half-life.
b. Marge, because the number of decays per unit time is halved in each half-life.
c. Homer, because it's safe to handle radioactive substances after two half-lives.
d. Both, because when all nuclei disintegrate the decay rate is also zero.
e. Neither, because one quarter of the nuclei are left after two half-lives.
Question 2
The International Date Line is a theoretical line following approximately the ______________ meridian.
Fill in the blank(s) with correct word