JEE Mains · Physics · STD 12 - 11. Dual nature of radiation and matter
Electron beam used in an electron microscope, when accelerated by a voltage of \(20\,kV\). has a de-Broglie wavelength of \(\lambda_0\). If the voltage is increased to \(40\,kV\). then the de-Broglie wavelength associated with the electron beam would be:
- A \(3 \lambda_0\)
- B \(9 \lambda_0\)
- C \(\frac{\lambda_0}{2}\)
- D \(\frac{\lambda_0}{\sqrt{2}}\)
Answer & Solution
Correct Answer
(D) \(\frac{\lambda_0}{\sqrt{2}}\)
Step-by-step Solution
Detailed explanation
When electron is accelerated through potential difference \(V\), then \(\text { K.E. }= eV\) \(\Rightarrow \lambda=\frac{ h }{\sqrt{2 m ( KE )}}=\frac{ h }{\sqrt{2 meV }}\) \(\therefore \quad \lambda \propto \frac{1}{\sqrt{ V }}\)…
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