A semiconducting device connected in series with a cell and a resistor indicates some current in the circuit. If the polarity of the battery is reversed, the current almost reduces to zero. The device may be:
Correct answer: C. A p-n junction
- A. A p-type semiconductor
- B. An n-type semiconductor
- C. A p-n junction
- D. An intrinsic semiconductor
Explanation
The correct answer is a p-n junction. A p-n junction diode allows current to flow freely when forward biased (positive to p-type and negative to n-type) but significantly restricts current flow when reverse biased, which is when the battery polarity is reversed. This behavior aligns perfectly with the description given in the question.Options A and B are incorrect because a p-type or an n-type semiconductor alone does not exhibit the described behavior without forming a junction. Option D, an intrinsic semiconductor, lacks the charge carriers and electric field required to block current flow under reverse bias conditions.
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About Electronics
A p-n junction forms when p-type and n-type semiconductor regions meet, creating a depletion layer, barrier potential and rectifying action. The work covers forward and reverse bias, junction current, diode characteristics, and how a diode converts alternating current into pulsating direct current through half-wave and full-wave rectification.
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