Probability — CSIR Net PYQ (Question 2)

A Probability previous-year question (PYQ) from Mathematical Physics (CSIR Net). Read the question, check the correct answer, then practise the full topic.

Question 2 of 18 · 3.5 marks

Consider two radioactive atoms, each of which has a decay rate of 1 per year. The probability that at least one of them decays in the first two years is

1 $\frac{1}{4}$
2 $\frac{3}{4}$
3 $1 - e^{- 4}$
4 $(1 - e^{- 2})^{2}$

Correct answer: Option 3

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This Probability PYQ is part of the Mathematical Physics section of CSIR Net. Browse more Probability questions or join the PhysicsByAaryan live batch for full conceptual coverage.