Question

determine the energy of 1.80 mol of photons for each of the following kinds of light. (assume three significant figures.) infrared radiation (1540) nm

Answer 1

      = 1540nm

          = 1540*10^-9 m    = 1.54*10^-6 m

C       = 3*10^8 m/sec

E       = hc/

          = 6.625*10^-34*3*10^8/1.54*10^-6

           = 1.3*10^-19 J

1.8 mole of photons = 1.8*6.023*10^23    = 1.084*10^24 photons

total energy    = 1.3*10^-19 * 1.084*10^24    = 1.4*10^5 J   = 140KJ