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If the fraction of the atoms of a radioactive material le...

If the fraction of the atoms of a radioactive material left after 120 years is 1/64, what is the half-life of the material?

A.

24 years

B.

20 years

C.

10 years

D.

2 years

Correct answer is B

Given amount remaining = \(\frac{1}{64}\)

= \(\frac{1}{64} = \frac{1}{(2)^{6}}\)

\(\therefore\) = \(\frac{120 \text {years}}{6}\) = 20 years

\(\Rightarrow\) T\(\frac{1}{2}\) = 20 years