An LED is constructed from a p-n junction based on a certain semi-conducting material whose energy gap is 1.9 eV. Then, the wavelength of the emitted light is

Options

A. `1.6xx10^(-8)m`
B. `9.1xx10^(-5)m`
C. `2.9xx10^(-9)m`
D. `6.5xx10^(-7)m`

Answer

D

Explanation

`E_(g)=1.9eV`
since, `E(eV)=(12400)/(lambda(Å))`
`implieslambda(Å)=(12400)/(1.9)=6526.32Å=6.5xx10^(-7)m`(approx).