A radioactive substance has half-life of 60 minute. During 3 hour, the amount of substance decayed would be

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Aicharya · Accepted Answer

$\begin{aligned} & N=N_0\left(\frac{1}{2}\right)^{\frac{t}{T_1 / 2}} \\ \therefore & \frac{N}{N_0} \\ \therefore & \left(\frac{1}{2}\right)^{\frac{t}{T_1 / 2}}\end{aligned}$ $\begin{array}{ll} \therefore & \frac{\mathrm{N}}{\mathrm{~N}_0}=\left(\frac{1}{2}\right)^{\frac{3 \times 60}{60}}=\left(\frac{1}{2}\right)^3 \\ & \therefore \quad \\ \therefore & \frac{\mathrm{~N}}{\mathrm{~N}_0}=\frac{1}{8} \end{array}$
The amount of substance decayed $=1-\frac{N}{N_0}$ $1-\frac{\mathrm{N}}{\mathrm{~N}_0}=1-\frac{1}{8}=\frac{7}{8}=87.5 \%$

A radioactive substance has half-life of 60 minute. During 3 hour, the amount of substance decayed would be

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