NURSING EXAM QUESTIONS
MICROBIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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What is half-life in radioactivity
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It is half the time for radioactive sources to become safe
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It is half the time for an atom to decay
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it is half the time it takes the activity of the source to decrease to zero
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It is time which takes to make the activity of the source to decrease to half
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Explanation:
Detailed explanation-1: -The half-life of a reaction is the time required for the reactant concentration to decrease to one-half its initial value. The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction: t1/2 = 0.693/k. Radioactive decay reactions are first-order reactions.
Detailed explanation-2: -When a radioactive nucleus decays, the activity of the atom decreases. This activity never reaches zero as there will always be some radioactive material remaining which will decay further. The activity of a radioactive source is measured using the unit becquerel (Bq).
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