The half-life of a radioactive element is 5 years, then the fraction of the radioactive substance that remains after 20 years is
A. $$\frac{1}{2}$$
B. $$\frac{1}{4}$$
C. $$\frac{1}{8}$$
D. $$\frac{1}{16}$$
Answer: Option D
Solution (By Examveda Team)
The fraction of a radioactive substance that remains after a certain time period is given by the formula:Fraction remaining = (1/2)^(time elapsed / half-life)Given that the half-life of the radioactive element is 5 years and we want to find the fraction remaining after 20 years, we substitute these values into the formula:
Fraction remaining = (1/2)^(20 / 5) = (1/2)^4 = 1/16So, after 20 years, only 1/16 of the radioactive substance remains.
This Question Belongs to Physics GK Chapter Wise >> Modern Physics
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