Question

The ratio of de-Broglie wavelengths for electrons accelerated through \(200\,V\) and \(50\,V\) is:

• A. \(1:2\)
• B. \(2:1\)
• C. \(3:10\)
• D. \(10:3\)

Hint:

Higher voltage \(\Rightarrow\) smaller wavelength.

Answer 1

The Correct Option is A

Concept: \[ \lambda \propto \frac{1}{\sqrt{V}} \] Ratio:
\[ \frac{\lambda_1}{\lambda_2} = \sqrt{\frac{V_2}{V_1}} = \sqrt{\frac{50}{200}} = \frac{1}{2} \] \[ \Rightarrow 1:2 \]