Question

The mean free path of conduction electrons in copper is about $4\times {10}^{-8}m$. Find the electric field which can give, on an average, $2eV$ energy to a conduction electron in a block of copper.

• A. $6\times {10}^{7}V/m$
• B. $7\times {10}^{7}V/m$
• C. $5\times {10}^{7}V/m$
• D. $5\times {10}^{9}V/m$

Answer 1

Answer: (C)

$5\times {10}^{7}V/m$

Energy$2$eV

$e{V}_0=2$eV

$\Rightarrow V_0=2$

Now, electric field $E=\frac{2}{4\times {10}^{-8}}=0.5\times {10}^8=5\times {10}^7$V/m