The schematic symbol of a light emitting diode $(LED)$ is:

The 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

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?

In an $LED$,when forward bias is increased (starting from zero),the intensity of emitted light will:

Consider the following statements $:$
$A.$ The junction area of a solar cell is made very large compared to a photodiode.
$B.$ Solar cells are not connected with any external bias.
$C.$ $\text{LED}$ is made of heavily doped $p-n$ junction.
$D.$ Increase of forward current results in continuous increase of $\text{LED}$ light intensity up to a saturation point.
$E.$ $\text{LED}$ must be connected in forward bias for the emission of light.
Which of the following statements are correct?

What kind of $p-n$ junction diode does not require any kind of bias?