Q. If isotopic distribution of C-12 and C-14 is 98% and 2% respectively then the number of C-14 atoms in 12 g of carbon is
A) $1.032 \times 10^{22}$
B) $3.01 \times 10^{22}$
C) 5.88$\times 10^{23}$
D) 6.023$\times 10^{23}$
Explanation
(a)
In 12 g carbon, mass of C-14 isotope $= 12 \times \frac{2}{100} = 0.24g$
$\therefore$ Number of C-14 atoms in 12 g of $C = \frac{0.24}{14} \times 6.02 \times 10^{23}$
$= 1.032 \times 10^{22}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.