Q. Given, that the abundances of isotopes _{54}Fe, _{56}Fe and _{57}Fe$\ are\ 5\%,90\%\ and\ 5\%,\$respectively, the atomic mass of Fe is
A) 55.85
B) 55.95
C) 55.75
D) 56.05
Explanation
(b)
Average atomic weight
$= \frac{54 \times 5 + 56 \times 90 + 57 \times 5}{100} = 55.95$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.