The material suitable for making a solar cell is

Photodiodes are mostly operated in reverse biased condition because

The semiconductor used for the fabrication of visible LEDs must at least have a band gap of (in $eV$)

The device that can detect optical signals is

$A$ photo cell is a device used to:

$A$ solar cell is to be fabricated for efficient conversion of solar radiation to emf using material $A$. The solar cell is to be mechanically protected with the help of a coating using material $B$. If the band gap energy of materials $A$ and $B$ are $E_{A}$ and $E_{B}$ respectively,then which of the following choices is optimum for better performance of the solar cell?