Question

An electron in accelerated through a potential difference of 45.5 V. The velocity acquired by it is $\left(inm{s}^{-1}\right)$

• A. zero
• B. 10⁶
• C. 4 × 10⁴
• D. 4 × 10⁶

Answer 1

The correct option is D

4 × 10⁶

$eV=\frac{1}{2}m{v}^2\Rightarrow v^2=\frac{2eV}{m}\Rightarrow v=\sqrt{\frac{2eV}{m}}=\sqrt{\frac{2\times 1.6\times {10}^{-19}\times 45.5}{9.1\times {10}^{-31}}}$

$\Rightarrow v=4\times {10}^{6}m{s}^{-1}$