Question detail

If a radioactive isotope has a half-life of 2 years and its initial activity is 1000 Bq, what will its activity be after 6 years?

Try the question, check the answer, then read the explanation to understand the curriculum point.

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At a glance

MCQ

Type

practice

Style

Topic

Atoms and nuclear radiation

Question

A. 125 Bq
B. 250 Bq
C. 500 Bq
D. 750 Bq

Answer

125 Bq

Explanation

125 Bq is correct because the worked solution uses remaining = initial / 2^n and substitutes the values from the question. This keeps activity, count rate, atomic number, mass number and neutron count distinct for Atomic structure.

Common mistake

Misunderstanding Half-Life Calculation

Students often confuse the concept of half-life with the total time for decay, thinking it is the time taken for all radioactive nuclei to decay rather than the time for half to decay.

Emphasize that half-life is the time required for half of the radioactive nuclei in a sample to decay, and practice calculating remaining activity after several half-lives.

Related flashcards

Flashcard 1 of 5

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A radioactive substance has a half-life of 5 years. If the initial count rate is 80 counts per minute, what will the count rate be after 15 years? Use the smoke alarm context to keep Half-lives and the random nature of radioactive decay distinct from nearby atomic and nuclear radiation ideas.