Photo-diode Photodetector – Rankers Physics

P-N Junction Diode and its applications: Practice Problem & Solution

In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R) Assertion (A): The photo-diode can be used as a photodetector to detect optical signals. Reason (R): It is easier to observe the change in the current with change in the light intensity, if a forward bias is applied to photodiode.  
If both (A) & (R) are true and the (R) is the correct explanation of the (A)
If both (A) & (R) are true but the (R) is not the correct explanation of the (A)
If (A) is true statement but (R) is false
If both (A) & (R) are false statements

Solution Explained:

To solve this problem, we apply the core principles of P-N Junction Diode and its applications. Understanding the underlying formula is key to arriving at the correct answer below:

Photo-diodes are operated in reverse bias because the fractional change in reverse current upon illumination is far larger and more easily measured than in forward bias.

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