Q129 / 155 · WBJEE 2022 · Physics
If the kinetic energies of an electron, an alpha particle and a proton having same de-Broglie wavelength are $\varepsilon_1, \varepsilon_2$ and $\varepsilon_3$ respectively, then
- Correct answerA$\varepsilon_1>\varepsilon_3>\varepsilon_2$
- B$\varepsilon_1=\varepsilon_2=\varepsilon_2$
- C$\varepsilon_1 < \varepsilon_3 < \varepsilon_2$
- D$\varepsilon_1>\varepsilon_2>\varepsilon_3$
Solution
$\lambda=\frac{\mathrm{h}}{\sqrt{2 \mathrm{mk}}}, \sqrt{\mathrm{mk}}=\mathrm{const}$
$\mathrm{k} \propto \frac{1}{\mathrm{~m}}, \varepsilon_1>\varepsilon_3>\varepsilon_2$
Hence, the correct answer is option: 'A'.