The $I-V$ characteristics of an $LED$ are correctly shown by which graph?

$A$ photodetector is made from a semiconductor $In_{0.53}Ga_{0.47}As$ with $E_g = 0.73 \, eV$. What is the maximum wavelength,which it can detect in $nm$?

Conductivity of a photodiode starts changing only if the wavelength of incident light is < 660 \, nm. The band gap of the photodiode is found to be $\left(\frac{x}{8}\right) eV$. The value of $x$ is: (Given, $h=6.6 \times 10^{-34} \, Js, c=3 \times 10^8 \, m/s, e=1.6 \times 10^{-19} \, C$)

$A$ $p-n$ photodiode is manufactured from a semiconductor with a band gap of $3.1 \,eV$. Which of the following wavelengths can be detected by it?

When light shines on a $p-n$ junction diode,the current $I$ versus voltage $V$ is observed as in the figure below. In which quadrant$(s)$ does the diode generate power,so that it can be used as a solar cell?

Which of the following statements is not correct in the case of light emitting diodes?