The average mass density of atomic nuclei is found to stay nearly constant at about…
PHYSICS · Single correct · A Level · Physics · Nuclear physics · Nuclear physics
Problem
The average mass density of atomic nuclei is found to stay nearly constant at about 2.3×1017kg m−3 for nuclei ranging from 4He to 208Pb. Which of the following gives the most appropriate reason for this constancy?
(a) The nuclear force is long-range and becomes stronger in heavier nuclei.
(b) The short-range nuclear force exhibits saturation, keeping the mean spacing between nucleons nearly the same for all values of A.
(c) Electromagnetic repulsion exactly cancels nuclear attraction in all stable nuclei, forcing a constant density.
(d) The gravitational attraction between the nucleons grows with A and compresses the nucleus so that the density remains constant.