Question

A container holds a pure sample of a radioactive substance with a half-life of 2 hours. Which of the following statements are true?
a) After 1 hour, less than 50 % of the original atoms in the container will have decayed.
b) After 1 hour, more than 50 % of the original atoms in the container will have decayed.
c) After 2 hours, 50 % of the original atoms in the container will have decayed.
d) After 4 hours, 25 % of the original atoms will have decayed.
e) After 4 hours, the total number of atoms in the container will be reduced by 75 %.

Answer 1

C, because a half-life is the amount of time it takes for half the atoms to decay.