A p-n photo diode is fabricated from a semiconductor with band gap of 2.8eV. Can it detect a wavelength of 6000nm?

Explanation

Given : `lambda` = 6000 nm
i.e.,`" "lambda = 6 xx 10^(6)`m
but energy `" " E = ("hc")/(lambda)`
`" " = (6.626 xx 10^(-34) xx 3 xx 10^(8))/(6 xx 10^(-6)) = 3.313`eV
Since incident energy is greater than the forbidden gap energy, photo diode can detect the radiation of wavelength 6 `mu`m .