A radioactive decay rate of radioactive elements is found to be 103 disintegrations per sec at a certain time. If the half-life of the element is 1 second, the decay rate after one second is _ and after 3 second is _.
Correct answer: A. 500, 125
- A. 500, 125
- B. 125,500
- C. 103, 103
- D. 100, 10
Explanation
The decay rate at t=0 is 1000Hz. at t=1=1000/21 =500/sec. at t=3=1000/23 =125/sec.
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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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