Discussion
If a radioactive element disintegrates for a period of time equal to its mean life, then the fraction of the original amount remaining undisintegrated is
Answer: D
The fraction remaining is \(\frac{1}{e}\).
Radioactive decay follows \(N = N_{0}e^{-\lambda t}\), and the mean life is \(\tau = \frac{1}{\lambda}\). After a time \(t = \tau\):
\[ \frac{N}{N_{0}} = e^{-1} = \frac{1}{e} \approx 0.37 \]
\(1 - \frac{1}{e}\) is the fraction that has decayed, and 1 − e and 2e are not fractions between 0 and 1.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development