Question 199: Atoms & Nuclei

Question

If a radioactive element having half-life of $$30 \mathrm{~min}$$ is undergoing beta decay, the fraction of radioactive element remains undecayed after $$90 \mathrm{~min}$$. will be

Accepted Answer

$t_{	ext {half }}=30 \mathrm{~min}$.
In 90 min. there will be 3 half lives
$$
\begin{aligned}
	ext { Number of remaining } & =\left(\frac{N_{0}}{2^{3}}ight) \\
& =\frac{N_{0}}{8}
\end{aligned}
$$
$	herefore \quad$ Fraction will be $\frac{1}{8}$

Answer

$$\frac{1}{16}$$

Answer

$$\frac{1}{4}$$

Answer

$$\frac{1}{8}$$

Answer

$$\frac{1}{2}$$

Atoms & Nuclei

If a radioactive element having half-life of $30 \mathrm{~min} is undergoing beta decay, the fraction of radioactive element remains undecayed after 90 \mathrm{~min}$. will be

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