Directions : In the following questions, A statement of Assertion (A)...
In forward bias condition, the depletion region of a p-n junction diode contracts and the majority charge carriers can cross the junction very easily. So, the resistance becomes low (ideally 0).
In reverse bias condition, the depletion region of p-n junction diode expands and the majority charge carriers cannot cross the junction. So, the resistance increases (ideally ∞).
So, the assertion and reason both are true and reason explains the assertion.
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Directions : In the following questions, A statement of Assertion (A)...
Assertion: Ideal diode shows zero resistance in forward bias and infinite resistance in reverse bias.
Reason: Depletion region of a p-n junction diode extends in reverse bias and contracts in reverse bias.
Explanation:
When a p-n junction diode is forward biased, the positive terminal of the battery is connected to the p-type material and the negative terminal is connected to the n-type material. This causes the holes in the p-type material and the electrons in the n-type material to move towards the junction, creating a forward current. In this case, the diode behaves like a closed switch, allowing current to flow freely.
In forward bias, the depletion region of the diode decreases, allowing the majority carriers (electrons in the n-type material and holes in the p-type material) to easily cross the junction and combine with each other. As a result, the diode shows zero resistance in forward bias.
On the other hand, when a p-n junction diode is reverse biased, the positive terminal of the battery is connected to the n-type material and the negative terminal is connected to the p-type material. This causes the majority carriers to move away from the junction, widening the depletion region. In this case, the diode behaves like an open switch, preventing current from flowing.
In reverse bias, the depletion region of the diode increases, creating a high barrier for majority carriers to cross the junction. As a result, the diode shows infinite resistance in reverse bias.
Conclusion:
Both the assertion and the reason are true. The assertion states that an ideal diode shows zero resistance in forward bias and infinite resistance in reverse bias, which is correct. The reason explains that the depletion region of a p-n junction diode extends in reverse bias and contracts in forward bias, which is also correct. Therefore, option A is the correct answer.