A 32g phosphorus is decayed and 2g remains undecayed after 60 days. The half-life of phosphorous is:
Correct answer: D. 15 days
- A. 5 days
- B. 6 days
- C. 10 days
- D. 15 days
Explanation
1 half life = 16g 2 half life = 8g 3 half life = 4g 4 half life = 2g 60/4=15 days
This question appeared on the NUMS 2021 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Half-life and Rate of Decay
Half-life is the time required for half the unstable nuclei in a sample to decay, and it remains constant for a particular radioactive nuclide. Questions use the exponential decay law, decay constant, activity, remaining quantity and mean life. Radioactive decay is random for individual nuclei but predictable for large samples.
Practise Nuclear Physics
1,254 free Nuclear Physics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Half-life and Rate of Decay questions
A certain radioactive isotope has a half-life of 50 days. Fraction of the material left behind after 100 days will be:
If the half-life of any radioactive nucleus is 0.693 years, what will be the value of decay constant?
The sample of radioactive element decayed after 5 half-lives is:
A 32g radioactive element decays and remains 2g after 60 days. What is the half- life of radioactive element?
The time taken for half the number of atoms of radioactive isotopes to missing is called:
A 32g radioactive elements decays and remains 2g after 60 days. What is half-life of this radioactive elements?