Through what potential difference should an electron be accelerated so that its de-Broglie wavelength becomes 0.4Å?

Explanation

To find the potential difference through which an electron should be accelerated to achieve a de-Broglie wavelength of 0.4 Å, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the de-Broglie Wavelength Formula**:
The de-Broglie wavelength (\( \lambda \)) of a particle is given by the formula:
\[
\lambda = \frac{h}{p}
...