Dual Nature of Radiation and Matter - Result Question 60
64. An electron of mass $m$ and charge $e$ is accelerated from rest through a potential difference of $V$ volt in vacuum. Its final speed will be
[1996]
(a) $\frac{eV}{2 m}$
(b) $\frac{eV}{m}$
(c) $\sqrt{\frac{2 eV}{m}}$
(d) $\sqrt{\frac{eV}{2 m}}$
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Answer:
Correct Answer: 64. (c)
Solution:
- (c) Kinetic energy of electron accelerated through a potential $V=eV$
$\Rightarrow \frac{1}{2} m v^{2}=eV$
$\Rightarrow v^{2}=\frac{2 eV}{m} \Rightarrow v=\sqrt{\frac{2 eV}{m}}$
