-
The half life of a radioactive nucleus is 50 days. The time interval (t2 – t1 ) between the time t2 when 2/3 of it has decayed and the time t1 when 1/3 of it had decayed is :
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- 30 days
- 50 days
- 60 days
- 15 days
Correct Option: B
N1 = N1 e–λt
| N1 = | N0 | |
| 3 |
| = N0e- λt2 | ||
| 3 |
| = e- λt2 ....(i) | ||
| 3 |
| N2 = | N0 | |
| 3 |
| N0 = N0e- λt1 | ||
| 3 |
| = e- λt1 | ||
| 3 |
Dividing equation (i) by equation (ii)
| = e- λ(t2 - t1) | ||
| 2 |
λ(t2 - t1) In 2
| t2 - t1 = | = T1/2 = 50 days | |
| λ |