When describing the energy of individual photons, the MKS unit of energy (J) is
large and cumbersome; so scientists use much smaller units such as the
electron volt.  one electron volt (ev) is 1.6 * 10^(-19) Joule.

(a) How many ev does a typical photon of radio, microwave, infrared,
visible, ultraviolet, X-ray, and gamma ray radiation carry?  Remember that
Planck's constant h = 6.63 * 10^(-34) J s.

(b) The mass of a proton is 1.67 * 10^-27 kg, and the mass of an electron
is 9.1 * 10^-31 kg.  The mass of a neutron is about 99.9% that of the mass
of a proton.  What is the rest mass energy, in ev, of a proton, a neutron and
an electron?  Remember that rest mass energy is E = mc^2 for any particle.

(c) Based on your answers above, about how many visible light photons
would have to strike your body to equal the energy of a high-speed proton
or electron striking your body?  How about gamma ray photons?