Question

Which of the following is a correct statement about current carrying conductor?

• A. On increasing temperature drifts speed of free electron decreases
• B. On increasing temperature drift speed of free electron increases
• C. On increasing temperature, drift speed of free electron remains same.
• D. On increasing P.D. average kinetic energy of electron decreases ( Neglected heating effect of electric current)

Answer 1

Answer: (A)

On increasing temperature drifts speed of free electron decreases

$vd=\frac{et}{m}E$
$t\downarrow$ as $T\uparrow ]$

As the temperature increases, the thermal agitation of the electrons increases thereby, increasing the number of collisions. Hence, drift velocity of the electrons decreases.