Physics Group - II (3110018)

Fermi energy $\left( {\mathrm{E}}_{\mathrm{F}} \right)$ $= 7.9 \mathrm{eV}$

Average energy  $\left( \overline{{\mathrm{E}}_0} \right)$ $= \frac{3}{5} {\mathrm{E}}_{\mathrm{F}}$  

Average energy  $\left( \overline{{\mathrm{E}}_0} \right)$ $= \frac{3}{5} \times 7 . 9$

Average energy  $\left( \overline{{\mathrm{E}}_0} \right)$ $= 4.47 \mathrm{eV}$  

Now, Speed of electron can be calculated: $\left( \overline{{\mathrm{E}}_0} \right)$ $= \frac{1}{2} \mathrm{m} {\mathrm{V}}^2$  

$\Rightarrow \mathrm{V} = \sqrt{\frac{2\overline{ {{\mathrm{E}}^{}}_0}}{\mathrm{m}}}$

$\Rightarrow \mathrm{V} = \sqrt{\frac{2 \times 4.74 \times 1.6 \times {10}^{-19}}{9.1 \times {10}^{-31}}}$

$\Rightarrow \mathrm{V} = 1.2 \times {10}^6 \mathrm{m}/\sec$