A radioactive isotope of a metal produced a reading of 188 Bq. Another reading of the activity was taken 4 hours later and the reading was 47.0 Bq. What is the half-life of this isotope?
A)4 hr
B)2 hr
C)1 hr
D)30 min

Question

A radioactive isotope of a metal produced a reading of 188 Bq.  Another reading of the activity was taken 4 hours later and the reading was 47.0 Bq.  What is the half-life of this isotope?
A)4 hr
B)2 hr
C)1 hr
D)30 min

Quizplus · Accepted Answer

The half-life can be determined by understanding that the activity of the isotope decreases by half every half-life period. From 188 Bq to 47 Bq, the activity reduces to a quarter (1/4) of its original value, indicating two half-lives have passed in 4 hours. Therefore, the half-life is 4 hours / 2 = 2 hours.

A Radioactive Isotope of a Metal Produced a Reading of 188