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 will $NOT$ be observed when a multimeter (operating in resistance measuring mode) probes connected across a component are reversed?

The photodiode is used to detect optical signals. These diodes are preferably operated in reverse biased mode because:

$A$ family uses $8 \; kW$ of power.
$(a)$ Direct solar energy is incident on the horizontal surface at an average rate of $200 \; W$ per square meter. If $20 \%$ of this energy can be converted to useful electrical energy, how large an area is needed to supply $8 \; kW$?
$(b)$ Compare this area to that of the roof of a typical house.

$A$ photo cell is a device used to:

For an $LED$ to emit light in the visible region of the electromagnetic spectrum,it can have an energy band gap in the range of (Planck's constant,$h = 6.6 \times 10^{-34} \ J s$ and speed of light,$c = 3 \times 10^8 \ m s^{-1}$ in vacuum).