Answer
$v_F = 1.39 \times 10^{6} m/s$
Work Step by Step
To find the Fermi speed, back to speed formula
$E_F = \frac{1}{2} mv_F^2$
Rearrange the equation
$v_F = \sqrt {\frac{2E_F}{m}}$
Where
$m_e=9.109\times 10^{-31} kg$
$8.80 \times 10^{-19} J$
So,
$v_F = \sqrt {\frac{2(8.80 \times 10^{-19} J)}{9.109\times 10^{-31} kg}}$
$v_F = 1.39 \times 10^{6} m/s$
