Dual Nature Of Matter Question 2

Question 2 - 24 January - Shift 2

An $\alpha$-particle, a proton and an electron have the same kinetic energy. Which one of the following is

correct in case of their De-Broglie wavelength:

(1) $\lambda _{\alpha}>\lambda_p>\lambda_e$

(2) $\lambda _{\alpha}<\lambda_p<\lambda_e$

(3) $\lambda _{\alpha}=\lambda_p=\lambda_e$

(4) $\lambda _{\alpha}>\lambda_p<\lambda_e$

Show Answer

Answer: (2)

Solution:

Formula: De Broglie wavelength

$\lambda_D=\frac{h}{p}=\frac{h}{\sqrt{2 mK}}$

$\therefore \lambda \propto \frac{1}{\sqrt{m}}$

$\because m _{\alpha}>m_p>m_e$

$\lambda_e>\lambda_p>\lambda _{\alpha}$