The time in which half of the given number of radioactive nuclei decay is known as
Correct answer: A. 1/2 life of radioactive element
- A. 1/2 life of radioactive element
- B. 2/3 life of radioactive element
- C. 1/4 life of radioactive element
- D. 2/5 life of radioactive element
Explanation
The half life is the interval in which half the undecayed nuclei present decay, and because decay is random with a constant probability per nucleus, that interval stays the same however much material remains. Carbon 14 has a half life of about 5730 years and iodine 131 about 8 days. The quantity is a property of the nuclide and cannot be altered by temperature or pressure.
This question appeared on the UHS MDCAT 2025 paper, which you can sit online with every answer explained.
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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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