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The half-lives of two radioactive nuclides A and B are 1 and 2 ~min respectively. Equal weights of A and B are taken separately and allowed to disintegrate for 4 ~min . What will be the ratio of weights of A and B disintegrated?

Options

  1. A1:1
  2. B5:4
  3. C1:2
  4. D1:3

Correct answer

B. 5:4

Step-by-step solution

For, A t_ 1 / 2 =1 ~min part of A remained after 4 minutes (i.e., 4 half- life) will be = 1 16 part of A disintegrated in the same period = 15 16 For B, t_ 1 / 2 =2 ~min Part of B remained after 4 minutes (i.e., 2 half life) = 1 4 part of B disintegrated in the same time = 3 4 Hence, ratio of disintegrated weights of A and B= 15 16 : 3 4 =15: 12=5: 4

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