Q 12-14-073JEE MainJEE Main 2024 (9 Apr, Shift 1)Easy
A light emitting diode (LED) is fabricated using GaAs semiconducting material whose band gap is $1.42\ \text{eV}$. The wavelength of light emitted from the LED is:
Answer: (C) $875\ \text{nm}$
$$\lambda = \frac{hc}{E_g} = \frac{1240\ \text{eV nm}}{1.42\ \text{eV}} \approx 873\ \text{nm} \approx 875\ \text{nm}$$
Solution by Sreeraj P, M.Sc Physics