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.

Options

• Both Assertion (A) and Reason (R) are true and (R) is the correct explanation of (A).

• Both Assertion (A) and Reason (R) are true and (R) is not the correct explanation of (A).

• Assertion (A) is true and Reason (R) is false.

• Assertion (A) is false and Reason (R) is also false.

Answer 1

Assertion (A) is true and Reason (R) is false.

Explanation:

At room temperature, an intrinsic semiconductor has an equal amount of conduction electrons and holes. However, due to the formation of electron-hole pairs, the quantity of charge carriers (electrons and holes) rises as temperature rises. At higher temperature ranges, this effect is more pronounced. The conductivity of the intrinsic semiconductor increases as the number of charge carriers rises. As a result, as the temperature rises, an intrinsic semiconductor's resistance drops. Intrinsic conduction is the term for this process.

However, Reason (R) is incorrect since an increase in the number of changes transported does not always imply a rise in both electrons and holes. In reality, depending on the material and temperature range, the quantity of electrons and holes might increase or decrease.