Answer:
9 minutes is the half life of the radioisotope.
Step-by-step explanation:
Given;
initial count rate = 7,600 counts per minute
final count rate = 1,900 counts per minute
elapsed time, t = 18 minutes
The half life of the radioisotope is calculated as;
Time (half life) --------------------------remaining count rate
0 ------------------------------7,600 counts per minute
x ------------------------------3,800 counts per minute
2x----------------------------- 1,900 counts per minute
thus, 2x = 18 minutes
x = 18 / 2
x = 9 minutes
Therefore, 9 minutes is the half life of the radioisotope.
