NEETPhysicsSemiconductors
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): When a forward-biased p-n junction diode and a reverse-biased p-n junction diode are connected in series across a DC source, the potential drop across the forward-biased diode is much greater than that across the reverse-biased diode. Reason (R): The reverse-biased diode has a wider depletion layer
Options
- ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
- BBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A)
- CAssertion (A) is true but Reason (R) is false
- DAssertion (A) is false but Reason (R) is true
Correct answer
D. Assertion (A) is false but Reason (R) is true
Step-by-step solution
In a series circuit, the potential drop across a component is directly proportional to its resistance ( V = IR ). A reverse-biased p-n junction diode has a wider depletion layer, which results in an extremely high resistance compared to a forward-biased diode. Therefore, when connected in series, almost the entire source voltage drops across the reverse-biased diode, making the potential drop across the forward-biased diode negligibly small. Thus, the Assertion is false, but the Reason is true. Answer: Assertion (A