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

Statement $-I$: $A$ photodiode operates in reverse bias.
Statement $-II$: The fractional change due to the photo-effects on the minority carrier dominated reverse bias current is more easily measurable than the fractional change in the forward bias current.

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

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).

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

Which one of the following symbols represents a photodiode?