The following graph represents:

The current in the forward bias is known to be more $(\sim mA)$ than the current in the reverse bias $(\sim \mu A)$. What is the reason then to operate the photodiodes in reverse bias?

The bandgap of the material of a photodiode is $2.0 \ eV$. What is the minimum frequency of radiation that this material can absorb?

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

What type of $p-n$ junction diode does not require forward bias to operate?

Consider a situation in which reverse biased current of a particular $P-N$ junction increases when it is exposed to light of wavelength $\lambda \le 621 \, nm$. During this process,enhancement in carrier concentration takes place due to the generation of hole-electron pairs. The value of the band gap is nearly (in $eV$):