An LED is constructed from a p-n junction based on a certain Ga-As-P semiconducting material whose energy is 1.9 eV. What is the wavelength of the emitted light?

Explanation

If `lamda` is the wavelength of emitted light, then
`E_(g)=(hc)/(lamda)`
or `lamda=(hc)/(E_(g))`
`=((6.63xx10^(-34))xx(3xx10^(8)))/((1.9)xx(1.60xx10^(-19)))`
`=6.5xx10^(-7)m=650nm`