(a) What is the energy, in joules, of a single photon of blue light
with a wavelength of 350 nanometers?  Remember that the speed of light
in vacuum is 3.0 * 10^8 m/sec and that Planck's constant (the letter "h")
is 6.63 * 10^(-34) kg m^2/sec.

(b) A typical hydrogen atom will be ionized if it is struck by a photon
carrying more than 2.1 * 10^(-18) joule of energy.  What is the maximum
wavelength of such a photon?  What is the minimum wavelength?

(c) What temperature would an object need to have for its thermal radiation
spectrum to peak at photons carrying 2.1 * 10^(-18) joule of energy?  How
does this temperature compare to the temperature at the surface of the Sun?