A certain radioactive mass decays from 64 gm to 2 gm in 20 days. What is its half - life?
Correct answer: B. 4 days
- A. 5 days
- B. 4 days
- C. 10 days
- D. 6 days
Explanation
Radioactive decay is an exponential decay process. Half life measures the time it takes for a given amount of the substance to become reduced by half as a consequence of decay; hence, half life is called half of decay.64-32-16-8-4-2 Half life=5Number of half lives= 20/5 = 4 days
Last updated
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.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
87Ra221 is a radioactive substance having half-life of 4 days. Find the probability that a nucleus undergoes decay after two half-lives.
A 32g phosphorus is decayed and 2g remains undecayed after 60 days. The half-life of phosphorous is:
A 32g radioactive element decays and remains 2g after 60 days. What is the half- life of radioactive element?
A 32g radioactive elements decays and remains 2g after 60 days. What is half-life of this radioactive elements?
A certain radioactive isotope has a half-life of 50 days. Fraction of the material left behind after 100 days will be: