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A radioactive sample decays 7 8 times its original quantity in 15 minutes. The half-life of the sample is

Options

  1. A5   min
  2. B7 . 5   min
  3. C15   min
  4. D30   min

Correct answer

A. 5   min

Step-by-step solution

Remaining amount of sample is = 1 - 7 8 = 1 8 Using radioactive decay law N = N 0 2 - t T 1 2 We have, 2 t T 1 2 = N 0 N = N 0 N 0 8 = 8 = 2 3 Then, t T 1 2 = 3 Thus, half life of the sample is T 1 2 = 5   min .

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