13.21 From the relation R = R0A1/3, where R0 is a constant and A is the mass number of a nucleus, show that the nuclear matter density is nearly constant (i.e. independent of A).

Hint: Nuclear density does not depend on the value of mass number.
Step 1: Write the formula of nuclear density.
We have the expression for nuclear radius as:
R=R0A1/3
where, R0=Constant
A=Mass number of the nucleus. 
Nuclear matter density, ρ=Mass of the nucleusVolume of the nucleus
Step 2: Find the nuclear density.
Let m be the average mass of the nucleon. Hence, mass of the nuleus=mA
ρ=mA43πR3=3mA4πR0A133=3mA4πR03A=3m4πR03
Hence, the nuclear matter density is independent of A. It is nearly constant.