Rankers Physics

Photoelectric Effects and deBroglie Equation: Practice Problem & Solution

An electron of mass m and charge e is accelerated from rest through a potential difference V in vacuum. Its final velocity will be (1996)
$\sqrt{\frac{2eV}{m}}$
$\sqrt{\frac{eV}{m}}$
$\frac{eV}{2m}$
$\frac{eV}{m}$

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Photoelectric Effects and deBroglie Equation. Understanding the underlying formula is key to arriving at the correct answer below:

The kinetic energy gained by the electron is equal to the work done by the electric field: $\frac{1}{2}mv^2 = eV$. Rearranging for velocity gives $v = \sqrt{\frac{2eV}{m}}$.

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