A sample of a radioactive element with an initial mass of 24 gm decayed to 3 gm in 36 minutes. How much of the original sample remained after the first 12 minutes?
Correct answer: A. 12g
- A. 12g
- B. 6g
- C. 2 g
- D. 8 g
Explanation
Since the half life was reduced by three levels in the span of 36 minutes (24 grams to 3 grams), this shows us that 36 minutes refers to 3 half-lives of the substance. Hence, one half-life is equal to 12 minutes, which would mean the substance would have reduced by one half-life as well i.e. to 12 grams.
Last updated
About Nuclear Physics
Atomic nuclei contain protons and neutrons, with nuclear size, mass defect and binding energy describing their stability. The work covers alpha, beta and gamma decay, decay equations, half-life and decay rate, along with radiation safety and medical applications such as imaging, radiotherapy and tracers.
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.