The photocurrent in a photodiode depends on

Assertion $(A)$: $Si$ and $GaAs$ are the preferred materials for solar cells.
Reason $(R)$: Both these materials have energy band gaps much below the energy level corresponding to the maximum solar irradiance in the solar spectrum.

For the emission of light,a light emitting diode $(LED)$ is:

$A$ $p-n$ 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:

On which principle does the $Vidicon$ work?

Consider the following statements $A$ and $B$ and identify the correct answer:
$A$. For a solar-cell,the $I-V$ characteristics lies in the $IV$ quadrant of the given graph.
$B$. In a reverse biased $pn$ junction diode,the current measured in $(\mu A)$ is due to majority charge carriers.