a
ફોટોનની ઊર્જા \({\text{E}}\,\, = \,\,{\text{h}}{f}\,\, = \,\,\frac{{{\text{hc}}}}{\lambda }\,\, = \,\,\frac{{6.6\,\, \times \,\,{{10}^{ - 34}} \times \,\,3\,\, \times \,\,{{10}^8}}}{{450\,\, \times \,\,{{10}^{ - 9}}}}\)
\( = \,\,4.4\,\, \times \,\,{10^{ - 19}}\,J\)