(a) What is the mass defect of the ${ }^{1} \mathrm{H}$ atom due to the binding energy of the electron (in the ground state)?
(b) Should we worry about this mass defect when we calculate the mass of the ${ }^{1} \mathrm{H}$ nucleus by subtracting the mass of one electron from the mass of the ${ }^{1} \mathrm{H}$ atom?