COMEDK2023PhysicsSemiconductors
An LED is constructed from a p-n junction diode using GaAsP. The energy gap is 1.9 eV . The wavelength of the light emitted will be equal to
Options
- A10.4 10⁻²⁶ ~m
- B654 ~nm
- C654 Å
- D654 10⁻¹¹ ~m
Correct answer
B. 654 ~nm
Step-by-step solution
The energy of light of wavelength is given by E=h v= h c Here, h= Planck's constant =6.63 10⁻³⁴ ~J - s aligned c & = speed of light =3 10^8 ~m / s E & = energy gap =1.9 eV & =1.9 1.6 10⁻¹⁹ ~J aligned Substituting the given values in Eq. (i), we get aligned = 6.63 10⁻³⁴ 3 10^8 1.9 1.6 10⁻¹⁹ & =6.54 10⁻⁷ ~m & 654 ~nm aligned Thus, the wavelength of light emitted from LED will be 654 ~nm .