There is a uniform electric field of strength ${10}^3$ V /m along y-axis. A body of mass 1 gm and charge ${10}^{-6}$ C is projected into the field from origin along the positive x-axis with a velocity 10 m/s. Its speed in m/s after 10 s is (Neglect gravitation)

Body moves along the parabolic path.

For vertical motion: By using v = u + at, we have

${\mathrm{v}}_{\mathrm{y}}=0+\frac{\mathrm{QE}}{\mathrm{m}}.\mathrm{t}=\frac{{10}^{-6}\times {10}^3}{{10}^{-3}}\times 10=10\mathrm{m}/\mathrm{s}$

For horizontal motion: Its horizontal velocity remains the same, i.e., after 10 s, horizontal velocity of body ${\mathrm{v}}_{\mathrm{x}}$ = 10 m/s.
Velocity after 10 s, v = $\sqrt{{\mathrm{v}}_{\mathrm{x}}^2+{\mathrm{v}}_{\mathrm{y}}^2}$ = 10✓2 m/s