c
બેન્ડ ગેપ ઉર્જા \({E_g} = \,\,\,\frac{{hc}}{\lambda }\)

અહી, \(h\,\, = \,\,6.6\,\, \times \,1{0^{ - 34}}\,J\,s\,;\,\,\,c\,\, = \,\,3\,\, \times \,\,{10^8}\,m\,{s^{ - 1}}\,\)

\(\lambda \, = \,\,2480\,\,nm\,\, = \,\,248\,\, \times \,\,{10^{ - 8}}\,m\,;\,\,\,1\,\,eV\,\, = \,\,1.6\,\, \times \,\,{10^{ - 19}}\,J\)

\(\therefore \,\,{E_g} = \,\,\frac{{6.6\,\, \times \,\,{{10}^{ - 34}} \times \,\,3\,\, \times \,{{10}^8}}}{{248\,\, \times \,\,{{10}^{ - 8}} \times \,\,1.6\,\, \times \,\,{{10}^{ - 19}}}}\,\,\,\, = \,\,0.04989\,\,\, \times \,\,{10^1}\,eV\,\,\,\, = \,\,0.4989\,eV\,\,\,\, \approx \,\,0.5\,\,eV\)