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

Answer

A

Explanation

Given, energy gap, `E_(g)=1.9 eV=1.9xx10^(-19)V`
We known that, `E_(g)=(hc)/(lambda) and lambda =(hc)/(E_(g))`
Wavelength of the emitted light,
`lambda=(6.63 xx 10^(-34)xx3xx10^(8))/(1.9xx1.6xx10^(-19))=6.5xx10^(-7)m`