Answer:
2.11eV
Explanation:
We know that speed of light is it's wavelength times frequency.
[tex]\therefore f=v/\lambda\\=(3\times10^8m/s)/(589mm\times1m/1\times 10^9nm)\\=5.09\times10^1^4s^-1 \ or \ 5.09\times10^1^4Hz[/tex]
Planck's constant is [tex]6.626\times 10^3^4Js[/tex]
The energy gap is calculated by multyplying the light's frequency by planck's constant:
[tex]E_c=5.09\times10^1^4s^-^1\times 6.626\times10^-^3^4Js\\\\=3.37\times 10^-^1^9J \ \ \ \ \ \ #1eV=1.06\times 10^-^1^9J\\\\=2.11eV[/tex]
Hence, the energy gap is 2.11eV
