Q. If $M$ is the atomic mass and $A$ is the mass number, packing fraction is given by
A) $\frac{M}{M - A}$
B) $\frac{M - A}{A}$
C) $\frac{A}{M - A}$
D) $\frac{A - M}{A}$
Explanation
(b) The mass excess per nucleon of isotopes of atom is known as packing fraction given by
$P = \frac{M - A}{A}$
Where $M$ is the actual mass of isotope and $A$ is its atomic mass.
Packing fraction is positive for isotope having very low or very high mass number and negative for all others.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.