11.2 Exercise 17

There is relatively little empty space between atoms in solids and liquids, so that the average density of an atom is about the same as matter on a macroscopic scale—approximately $\text{10}^{3} \text{kg}/\text{m}^{3}$. The nucleus of an atom has a radius about $\text{10}^{- 5}$ that of the atom and contains nearly all the mass of the entire atom. (a) What is the approximate density of a nucleus? (b) One remnant of a supernova, called a neutron star, can have the density of a nucleus. What would be the radius of a neutron star with a mass 10 times that of our Sun (the radius of the Sun is $7 \times \text{10}^{8} \text{m}$)?