Homer says that we can safely use nuclear power because all ...

[Mr.Thesaxman]

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

[ambernicolefink]

Answer to Question 1

e

Answer to Question 2

180

[Mr.Thesaxman]

Excellent

[aliotak]

TYSM