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For a radioactive sample, the initial activity of the material was 8 cps and after 3 h it becomes 1 cps. The half-life of the sample is

Options

  1. A2   h
  2. B1 h
  3. C3   h
  4. D4   h

Correct answer

B. 1 h

Step-by-step solution

Here A 0 = 8 counts, A = 1 count and t = 3 h . A A 0 = 1 2 n ⇒ 1 8 = 1 2 n or 1 2 3 = 1 2 n ⇒ n = 3 So, T 1 / 2 = t n = 3 3 = 1 h

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