WBJEE · Physics · Nuclear Physics
Half-life of a radioactive substance is 20 minute. The time between \(20 \%\) and \(80 \%\) decay will be :
- A \(20 \mathrm{~min}\)
- B \(30 \mathrm{~min}\)
- C \(40 \mathrm{~min}\)
- D \(25 \mathrm{~min}\)
Answer & Solution
Correct Answer
(C) \(40 \mathrm{~min}\)
Step-by-step Solution
Detailed explanation
Hints : For \(20 \%\) decay \(\frac{80 \mathrm{~N}_0}{100}=\mathrm{N}_0 e^{-\lambda t_1}\) For \(80 \%\) decay \(\frac{20 N_0}{100}=N_0 e^{-\lambda t_2}\) On dividing…
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