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Question: Answered & Verified by Expert
A radioactive sample at some instant has a disintegration rate of 5000 disintegrations per minute. After 5 minutes, the rate becomes 1250 disintegrations per minute. Then, the decay constant (per minute) is
PhysicsAtomic PhysicsJEE Main
Options:
  • A 0.4  ln  2
  • B 0.2  ln  2
  • C 0.1  ln  2
  • D 0.8  ln  2
Solution:
1503 Upvotes Verified Answer
The correct answer is: 0.4  ln  2
A A 0 = 1 2 5 0 5 0 0 0 = 1 4 = 1 2 t T

T = t 2 = 5 2

λ=ln2T=25ln2

   =0.4 ln2

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