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:

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.