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Assertion (A): A p-n junction has high resistance in the reverse direction. Reason (R): Applying reverse bias increases the width of the depletion layer.

Difficulty: Easy

Correct Answer: Both A and R are true and R is correct explanation of A

Explanation:


Introduction / Context:
Reverse-bias characteristics of p-n junctions underpin rectification and blocking behavior in diodes. Understanding depletion layer modulation explains the high reverse resistance.


Given Data / Assumptions:

  • Junction: p-n silicon diode.
  • Bias: reverse voltage applied.


Concept / Approach:
Reverse bias increases built-in potential, widens the depletion region, and lowers carrier injection, so only a tiny leakage current flows. This corresponds to a very large effective resistance.


Step-by-Step Solution:

Step 1: Reverse bias raises the barrier.Step 2: Depletion region width increases, reducing majority-carrier flow.Step 3: Leakage is limited to minority carriers; current is very small.Step 4: Hence reverse resistance is high and R explains A.


Verification / Alternative check:

I-V characteristics of diodes show microampere to nanoampere reverse currents until breakdown, corroborating high resistance.


Why Other Options Are Wrong:

B: R directly explains A, not merely co-occurring.C/D/E: Each contradicts standard diode theory.


Common Pitfalls:

Assuming zero current under reverse bias; there is always small leakage until breakdown.


Final Answer:

Both A and R are true and R is correct explanation of A
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