Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
**Assertion A:** Photodiodes are preferably operated in reverse bias condition for light intensity measurement.
**Reason R:** The current in the forward bias is more than the current in the reverse bias for a $p$-$n$ junction diode.
In the light of the above statements, choose the correct answer from the options given below:
Answer: (B) Both A and R are true but R is NOT the correct explanation of A
A photodiode is used in reverse bias because the small reverse current changes by a large fraction when light falls on it, making it sensitive to intensity. A is true.
R is also true (forward current is much larger), but it is not the reason; the reason is the large fractional change of the reverse (minority carrier) current.
Solution by Sreeraj P, M.Sc Physics