Question

Assertion : The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased.

Reason : On increasing temperature, conductivity of metallic wire decreases.

• A. Both (A) and (R) are true and (R) is the correct explanation of A
• B. Both (A) and (R) are true but (R) is not the correct explanation of A.
• C. (A) is true but (R) is false
• D. (A) is false but (R) is true

Answer 1

Answer: (B)

Both (A) and (R) are true but (R) is not the correct explanation of A.

If the temperature of a metallic wire is increased, its resistance also increases since $\alpha$ is positive for metals, which there by tries to obstructs the flow of current which reduces the drift velocity.