The active area of a solar cell is $......$ so that the power obtained $......$.

$A$ photodiode is fabricated from a semiconductor with a bandgap of $2.5 \ eV$. Can it detect a wavelength of $6000 \ \mathring{A}$?

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

The current in the forward bias is known to be more $(\sim mA)$ than the current in the reverse bias $(\sim \mu A)$. What is the reason then to operate the photodiodes in reverse bias?

Which one of the following statements is '$WRONG$' regarding $LED$?

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).