Photon fundamentals.
((a)) Show that hc=1240 eV⋅nm.
((b)) Calculate the energy of a photon with each of the following wavelengths: 650 nm (red light); 450 nm (blue light); 0.1 nm (x-ray); 1 mm (typical for the cosmic background radiation).
((c)) Calculate the number of photons emitted in one second by a 1-milliwatt red He-Ne laser (λ=633 nm).