Assertion (A): The resistance of an intrinsic semiconductor decreases with an increase in its temperature. Reason (R): The number of conduction electrons as well as hole increase in an intrinsic semiconductor with the rise in its temperature

Question: Assertion (A): The resistance of an intrinsic semiconductor decreases with an increase in its temperature. Reason (R): The number of conduction electrons as well as hole increase in an intrinsic semiconductor with the rise in its temperature

The correct answer is –

Explanation:

In an intrinsic semiconductor, the number of conduction electrons and holes is equal at room temperature. However, the number of charge carriers (electrons and holes) increases with an increase in temperature due to the generation of electron-hole pairs. This effect is more pronounced in higher temperature ranges.

The increase in the number of charge carriers leads to an increase in the conductivity of the intrinsic semiconductor. Therefore, the resistance of an intrinsic semiconductor decreases with an increase in temperature. This phenomenon is known as intrinsic conduction.

However, the reason (R) is false because the increase in the number of charge carriers does not necessarily mean an increase in both electrons and holes. In fact, the number of electrons and holes may increase or decrease depending on the material and the temperature range. Therefore, the reason (R) is not a correct explanation for the assertion (A).