Question

The mean free path of electrons in a metal is $4\times {10}^{-8}$m. The electric field which can give on an average 2 eV energy to an electron in the metal will be in units V/m:

• A. $5\times 10^{-11}$
• B. $8\times 10^{-11}$
• C. $5\times 10^7$
• D. $8\times 10^7$

Answer 1

The correct option is C $5\times 10^7$

Energy $=2eV$

${eV}_0=2{eV}_0$

$\Rightarrow V_0=2$

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