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JEE Main202228 Jul 2022Morning ShiftPhysicsNuclear PhysicsActual

The half life period of a radioactive substance is 60 days. The time taken for 7 8 th of its original mass to disintegrate will be :

Options

  1. A120 days
  2. B130 days
  3. C180 days
  4. D20 days

Correct answer

C. 180 days

Step-by-step solution

Given half life period of a radioactive substance is t 1 2 = 60 days. Here, 7 8 th of radioactive substance disintegrates means 1 8 th remains or 1 2 3 . ∴     3 half lives = 3 × 60 = 180   days  

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