Question

A metallic block has no potential difference applied across it, then the mean velocity of free electrons is $T$ = absolute temperature of the block)

• A. Proportional to $T$
• B. Proportional to $\sqrt{T}$
• C. Zero
• D. Finite but independent of temperature

Answer 1

Answer: (B)

Proportional to $\sqrt{T}$

Answer 2

In the absence of external electric field mean velocity of free electron (V_rms) is given by $V_{rms} = \sqrt{\frac{3KT}{m}} \Rightarrow V_{rms} \propto \sqrt{T}$