Q164 / 180 · KCET 2022 · Physics
A charged particle is moving in an electric field of $3 \times 10^{-10} \mathrm{Vm}^{-1}$ with mobility $2.5 \times 10^6 \mathrm{~m}^2 / \mathrm{V}$-s, its drift velocity is
- A$8.33 \times 10^{-4} \mathrm{~m} / \mathrm{s}$
- B$25 \times 10^4 \mathrm{~m} / \mathrm{s}$
- C$1.2 \times 10^{-4} \mathrm{~m} / \mathrm{s}$
- Correct answerD$7.5 \times 10^{-4} \mathrm{~m} / \mathrm{s}$
Solution
Given, electric field, $E=3 \times 10^{-10} \mathrm{Vm}^{-1}$
Mobility, $\mu=25 \times 10^6 \mathrm{~m}^2 / \mathrm{V}-\mathrm{s}$
If drift velocity is $v_d$, then we know that
$$
\begin{aligned}
\mu & =\frac{v_d}{E} \Rightarrow v_d=\mu E \\
& =25 \times 10^6 \times 3 \times 10^{-10}=7.5 \times 10^{-4} \mathrm{~m} / \mathrm{s}
\end{aligned}
$$
Hence, the correct answer is option: 'D'.