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 junction diode.
In the light of the above statement, choose the correct answer from the options given below :
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 junction diode.
In the light of the above statement, choose the correct answer from the options given below :
- (A) is false but is true
- (B)Both and are true but is NOT the correct explanation of ✓ Correct
- (C) is true but is false
- (D)Both and are true and is the correct explanation of
Answer: (B)
Solution
A photodiode is operated in reverse bias because its small reverse current changes markedly with the light falling on it and is easy to track, so the assertion is correct. It is also true that the forward current of a junction diode greatly exceeds its reverse current, so the reason is itself a correct statement. However, the choice of reverse bias rests on the sensitivity of the reverse current to illumination, not on the forward current being larger, so the reason does not account for the assertion. Both statements are true, but the reason is not the correct explanation of the assertion.
JEE Main · 2023 · 24 Jan 2023 · Shift 1 · Single correct option