Q. The energy gap of silicon is $1.5\ eV$. At what wavelength the silicon will stop to absorb the photon
A) 8250 $\mathring{\mathrm{A}}$
B) 7250 $\mathring{\mathrm{A}}$
C) 6875.5 $\mathring{\mathrm{A}}$
D) 5000 $\mathring{\mathrm{A}}$
Explanation
(a) $\lambda = \frac{hc}{E} = \frac{6.6 \times 10^{- 34} \times 3 \times 10^{8}}{1.5 \times 1.6 \times 10^{- 19}} = 8.25 \times 10^{- 7}m = 8250\mathring{\mathrm{A}}$
The photon having wavelength equal to $8250\mathring{\mathrm{A}}$ or more than this will not be able to overcome the energy gap of silicon
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.