JAMB - Physics (1992 - No. 40)
After three half lifes, the fraction of a radioactive material that has decayed is
\(\frac{1}{8}\)
\(\frac{1}{3}\)
\(\frac{2}{3}\)
\(\frac{7}{8}\)
説明
I = \(\frac{1}{2}\) \(\Rightarrow\) \(\frac{1}{4}\) \(\Rightarrow\) \(\frac{1}{8}\)
Fraction decayed = 1 - \(\frac{1}{8}\)
= \(\frac{7}{8}\)
Fraction decayed = 1 - \(\frac{1}{8}\)
= \(\frac{7}{8}\)