Which property of nuclear force explains the approximate constancy of binding energy per nucleon with mass number A for nuclei in the range 30 < A < 170?
The constancy of binding per nucleon in the range of 30< A < 170 is explained by the property of the saturation effect of nuclear force. According to the saturation effect of nuclear force, for heavy nuclei, nuclear size is greater than the range of nuclear force. So a nucleon interacts only with its neighbouring nucleon.