KCET2023PhysicsSemiconductors
The energy gap of an LED is 2.4 eV . When the LED is switched ON, the momentum of the emitted photons is
Options
- A1.28 10⁻²⁷ ~kg ~ms ⁻¹
- B2.56 10⁻²⁷ ~kg ~ms ⁻¹
- C1.28 10⁻¹¹ ~kg ~ms ⁻¹
- D0.64 10⁻²⁷ ~kg ~ms ⁻¹
Correct answer
C. 1.28 10⁻¹¹ ~kg ~ms ⁻¹
Step-by-step solution
Energy gap of LED, E_g=2.4 eV We know that E_g= h c h = E_g c Momentum of emitted photon aligned p & = h E_g c & = 24 1.6 10⁻¹⁹ 3 10^8 & =1.28 10⁻¹¹ ~kg - ms ⁻¹ aligned