(Given, mass of electron $=9 \times 10^{-31} \mathrm{~kg}$, electric charge $=1.6 \times 10^{-19} \mathrm{C}$ )
$\mathrm{qE} =\mathrm{qVB}$
$\mathrm{E} =\mathrm{VB}$
$=\sqrt{\frac{2 \times \mathrm{KE}}{\mathrm{m}}} \times \mathrm{B}$
$=\sqrt{\frac{2 \times 5 \times 1.6 \times 10^{-19}}{9 \times 10^{-31}}} \times 3 \times 10^{-6}$
$=4 \mathrm{~N} / \mathrm{C}$



