If the decay or disintegration constant of a radioactive substance is λ, then its half-life and mean life are respectively:
Correct answer: B. Option B
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation
The half-life of a radioactive substance is the time it takes for the number of radioactive atoms to decrease to half of its original value. The mean life of a radioactive substance is the average time that a radioactive atom will exist before it decays. The half-life is given by t½ = loge2/λ, where λ is the decay constant. The mean life is given by τ = 1/λ.
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About Half-life and Rate of Decay
Half-life is the time required for half the unstable nuclei in a sample to decay, and it remains constant for a particular radioactive nuclide. Questions use the exponential decay law, decay constant, activity, remaining quantity and mean life. Radioactive decay is random for individual nuclei but predictable for large samples.
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