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NEET
Exam
NEET
Subject
Physics
Chapter
Semiconductors

NEET · Physics · Semiconductors

Given below are two statements : one is labelled as Assertion A and...

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R

Assertion A: Photodiodes are used in forward bias usually for measuring the light intensity.

Reason R: For a p−np - n junction diode, at applied voltage VV the current in the forward bias is more than the current in the reverse bias for ∣Vz∣>±V≥∣V0∣ where\left|{V}_{z}\right| > \pm V \ge \left|{V}_{0}\right| where{V}_{0}isthethresholdvoltageandis the threshold voltage and{V}_{z} is the breakdown voltage.

In the light of the above statements, choose the correct answer from the options given below

Options

  1. ABoth A and R are true and R is correct explanation A
  2. BBoth A and R are true but R is NOT the correct explanation A
  3. CA is false but R is true
  4. DA is true but R is false

Correct answer

C. A is false but R is true

Step-by-step solution

Photodiodes are operated in reverse bias condition. The change in saturation reverse current in a photodiode with reverse bias is directly proportional to the change in light intensity, thus can be precisely measured.

Current in forward bias (for applied voltageV≥V0V \ge {V}_{0}) is always greater than current in reverse bias (for V≤VzV \le {V}_{z}) in a p−np - n junction diode.

Hence, Assertion if false but Reason is true.

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