Question

After an interval on one day ${1/6}^{th}$ of the initial amount of a radioactive material remains in a sample. Then its half life is

• A. 12 hrs
• B. 6 hrs
• C. 3 hrs
• D. 1.5 hrs

Answer 1

Answer: (B)

6 hrs

Answer 2

Here $\frac{1}{16} = \frac{1}{2^4} \, i.e. \, \left( \frac{1}{2} \right)^4 = \left( \frac{1}{2} \right)^n \, i.e. \, n = 4.$ Half life = $\frac{24}{4}$ = 6 hr.