Q 12-14-115JEE MainJEE Main 2022 (25 Jul, Shift 1)Easy
The energy band gap of a semiconducting material to produce violet (wavelength $= 4000\ \text{Å}$) LED is ______ eV. (Round off to the nearest integer)
Numerical value type. Enter your answer.
Answer: 3
$$E_g = \frac{hc}{\lambda} = \frac{12400\ \text{eV Å}}{4000\ \text{Å}} = 3.1\ \text{eV}\approx3\ \text{eV}$$
Solution by Sreeraj P, M.Sc Physics