A particle of mass 0.5 g and charge $10 \mu \mathrm{C}$ is subjected to a uniform electric field of $8…
A particle of mass 0.5 g and charge $10 \mu \mathrm{C}$ is subjected to a uniform electric field of $8 \mathrm{NC}^{-1}$. If the particle is initially at rest, the velocity of the particle after a time of 5 seconds is
$5 \mathrm{~ms}^{-1}$
$0.5 \mathrm{~ms}^{-1}$
$8 \mathrm{~ms}^{-1}$
$0.8 \mathrm{~ms}^{-1}$
Solution
For charged particle,
$\mathrm{m}=0.5 \mathrm{~g}, \mathrm{q}=10 \mu \mathrm{c}, \mathrm{E}=8 \mathrm{NC}^{-1}, \mathrm{t}=5 \mathrm{~s}$
$\therefore$ Acceleration, $\mathrm{a}=\frac{\mathrm{qE}}{\mathrm{m}}$
$\therefore \quad$ Velocity after time t is
$\begin{aligned}
& v=u+a t=0+\left(\frac{q E}{m}\right) . t \\
& =\frac{10 \times 10^{-6} \times 8 \times 5}{0.5 \times 10^{-3}}=0.8 \mathrm{~ms}^{-1}
\end{aligned}$