Q156 / 160 · TS EAMCET 2024 (09 May Shift 1) · Physics
The half-life of a radioactive substance is 12 minutes. The time gap between $28 \%$ decay and $82 \%$ decay of the radioactive substance is
- A6 minutes
- B18 minutes
- C12 minutes
- Correct answerD24 minutes
Solution
Given half-life $\mathrm{T}_{1 / 2}=12$ minutes.
Time gap between $28 \%$ decay i.e., $100-100 \times \frac{28}{100}=72$ and $82 \%$ decay i.e., $100-100 \times \frac{82}{100}=18$
Therefore $72 \xrightarrow{t_{1 / 2}=12 \mathrm{~min}} 36 \xrightarrow{t_{1 / 2}=12 \mathrm{~min}} 18$
so time gap $=12+12=24$ minutes
Hence, the correct answer is option: 'D'.