Question

3.8 days is the half-life period of a sample. After how many days, the sample will become 1/8th of the original substance.

• A. 11.4
• B. 3.8
• C. 3
• D. None of these

Answer 1

Answer: (A)

11.4

Answer 2

$\frac{N}{N_{0}} = \left( \frac{1}{2} \right)^{n} \Rightarrow \frac{1}{8} = \left( \frac{1}{2} \right)^{n} \Rightarrow n = 3$

Now $t = n \times T_{1/2} = 3 \times 3.8 = 11.4\mspace{6mu} days$