Q. Carbon – 14 decays with half-life of about 5,800 years. In a sample of bone, the ratio of carbon – 14 to carbon – 12 is found to be $\frac{1}{4}$ of what it is in free air. This bone may belong to a period about $x$ centuries ago, where $x$ is nearest to
A) $2 \times 58$
B) 58
C) 58/2
D) $3 \times 58$
Explanation
(a) To becomes $\frac{1}{4}th$, it requires time of two half lives $i.e.,t = 2\left( T_{1/2} \right) = 2 \times 5800 = 2 \times 58\ centuries$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.