The laptop PCs,modern electronic watches,and calculators use the following for display:

$A$ $p-n$ photodiode is made of a material with a band gap of $2.0\, eV$. The minimum frequency of the radiation that can be absorbed by the material is nearly:

Assertion : Diode lasers are used as optical sources in optical communication.
Reason : Diode lasers consume less energy.

Why is the $I-V$ characteristic of a solar cell drawn in the fourth quadrant of the coordinate system?

Three photodiodes $D_{1}, D_{2}$ and $D_{3}$ are made of semiconductors having band gaps of $2.5 eV, 2 eV$ and $3 eV$,respectively. Which one will be able to detect light of wavelength $600 nm$?

$A$ photodetector is fabricated from a semiconductor with a band gap $E_g = 0.73 \, eV$. What is the maximum wavelength (in $nm$) it can detect?