Question

On increasing the temperature of a conductor. its resistance increases because the

• A. relaxation time increases
• B. mass of electron increases
• C. electron density decreases
• D. relaxation time decreases

Answer 1

Answer: (D)

relaxation time decreases

Answer 2

We have $R = \frac{m}{ne^2 \tau} . \frac{\lambda}{A}$
From this relation when temperature increases $\tau$ decrease, so that relaxation time decreases.