Resistivity of a Semiconductor – Rankers Physics

Basics of Current: Practice Problem & Solution

Assertion (A): The resistivity of a semiconductor increases with temperature. Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature thereby increasing its resistivity.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Basics of Current. Understanding the underlying formula is key to arriving at the correct answer below:

For a semiconductor, resistivity actually \(\text{decreases}\) with increasing temperature because more charge carriers (electrons and holes) are generated. The reason given describes the behavior of conductors, where increased atomic vibrations impede electron flow, increasing resistivity. Thus, both Assertion (A) and Reason (R) are false for a semiconductor.

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