For silicon , given

Wavelength of light that excite an electron from the valence to the condiction band in silicon is

Options

A. `1022 nm`
B. `1039 nm`
C. 1022 pm
D. 872 pm

Answer

b

Explanation

`E_(g) = 115 kJ mol^(-1)`
`= (115 xx 10^(3))/(6.02 xx 10^(23)) =` per electron
`E_(g) = hv = (hc)/(lambda)`
`:. lambda = (hc)/(E_(g)) = (6.02 xx 10^(-36) Js xx 3 xx 10^(8) ms^(-1) xx 6.02 xx 10^(23))/(115 xx 10^(3)J)`
`= 1039 xx 10^(-8) m= 1039 nm`