Q. A signature, written in carbon pencil weights 1 mg. What is the number of carbon atoms present in the signature?
A) $5.02 \times 10^{23}$
B) $5.02 \times 10^{20}$
C) $6.02 \times 10^{20}$
D) $0.502 \times 10^{20}$
Explanation
(d)
$\because\$Number of atoms present in 12 g carbon
$= 6.023 \times 10^{23}$
$\therefore$ No. of atoms present in 1 mg carbon
$= \frac{6.023 \times 10^{23} \times 1}{12 \times 1000}$
$= 0.502 \times 10^{20}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.