JEE Main202227 Jul 2022Evening ShiftPhysicsNuclear PhysicsActual
The activity of a radioactive material is 6 . 4 × 10 - 4 curie. Its half life is 5 days. The activity will become 5 × 10 - 6 curie after
Options
- A7 days
- B15 days
- C25 days
- D35 days
Correct answer
D. 35 days
Step-by-step solution
Given here, A 0 = 6 . 4 × 10 - 4 Curie and A = 5 × 10 − 6 Curie Half life, T 1 2 = 5 days The activity of a radioactive sample at time t is given by, A = A 0 1 2 t T 1 2 ⇒ 5 × 10 - 6 6 . 4 × 10 - 4 = 1 2 t 5 ⇒ 7 = t 5 ⇒ t = 35   days