Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: A diode under reverse-biased condition provides very small current which is nearly independent of voltage until a critical limit at which the current increases drastically.
Reason R: Below the critical voltage limit, only majority charge carriers flow which increases drastically above critical voltage.
choose the correct answer from the options given below:

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
In a p-n junction diode, reverse bias occurs when the n-region is connected to a higher potential than the p-region. This increases the barrier height, preventing majority carrier flow but allowing a small number of minority carriers to cross.

Step 2: Key Formula or Approach:
The reverse current consists of a reverse saturation current due to minority carriers. At a high enough reverse voltage (Breakdown voltage), the current increases sharply due to Zener or Avalanche breakdown.

Step 3: Detailed Explanation:
Assertion A is correct: In reverse bias, a very small "reverse saturation current" flows, which is nearly constant until the breakdown voltage is reached. At breakdown, the current increases drastically.
Reason R is incorrect: Below the breakdown limit, the current is due to minority charge carriers, not majority carriers. Majority carriers are pushed away from the junction in reverse bias. Above the critical voltage, current increases due to carrier multiplication or tunneling, but the statement about majority carriers flowing below the limit is fundamentally wrong.

Step 4: Final Answer:
Assertion A is true, but Reason R is false.