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NTA Abhyas JEE Main2020PhysicsNuclear PhysicsPractice

Half-life of radioactive substance is 3 .20 h . What is the time taken for 75% of substance to be used?

Options

  1. A6 .4 h
  2. B12 h
  3. C4 .18 day
  4. D1 .2 day

Correct answer

A. 6 .4 h

Step-by-step solution

N 0 → 1 N 0 2 → 2 N o 4 Remaining substance after two half lives is N 0 4 (or) the substance used during this time = N 0 - N 0 4 = 3 N 0 4 = 75 % N 0

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