Verified Solution • 2025–26 Session moderate

QNEET-2022-Ph-541: NEET 2022 Physics - Class 12 NEET-2022-Ph-541 Solution: At any instant two elements \(X_1\) and \(X_2\) have same…

At any instant two elements X1X_1 and X2X_2 have same number of radioactive atoms. If the decay constant of X1X_1 and X2X_2 are 10λ10\lambda and λ\lambda respectively then the time when the ratio of their atoms becomes 1/e1/e respectively will be: 15λ\frac{1}{5\lambda} 111λ\frac{1}{11\lambda} 19λ\frac{1}{9\lambda} 16λ\frac{1}{6\lambda}

Multiple Choice Options

  • A 15λ{1 \over {5\lambda }} 5 _ 1 _
  • B 111λ{1 \over {11\lambda }} 11 _ 1 _
  • C 19λ{1 \over {9\lambda }} 9 _ 1 _
  • D 16λ{1 \over {6\lambda }} 6 _ 1 _

Step-by-Step Verified Solution

Number of radioactive nuclei at any time is N = N 0 e _ _ t Initial number of nuclei is same for sample X 1 & X 2 . Let after time 't' the ratio of their atoms become 1 e _ N 0 e _ 10 _ _ t N 0 e _ _ _ t = 1 e _ e _ 9 _ t = e _ 1 _ t = 1 9 _ Hence, t = 1 9 _

Related Learning Resources & Exam Preparation

NEET PYQ Question Bank
Browse year-wise authentic previous years' questions with solutions
Authentic CBT Mock Tests
Simulate official exam environment with live timer and percentile scoring