The activity of a radioactive material is Ci. If the half life of the material is 5 days, after how many days the activity will become ?
- (A)30 days
- (B)35 days✓ Correct
- (C)40 days
- (D)25 days
Answer: (B)
Solution
Activity is proportional to the number of nuclei: . Here, . This means 7 half-lives have passed. Total time = days.
JEE Main · 2022 · 29 Jun 2022 · Shift 1 · Single correct option