Question

An electron of a velocity x is found to have a certain value of de Broglie wavelength. The velocity to be possessed by the neutron to have the same de Broglie wavelength is

(Given $m_e=9.1\times 10^{-28}g,m_n=1.674\times 10^{-24}g$ )

• A. x
• B. $\frac{x}{1840}$
• C. 1840 x
• D. None

Answer 1

Answer: (B)

$\lambda$ electron $=\lambda$ neutron

$\frac{h}{m_e{V}_e}=\frac{h}{m_n{V}_n}$

So $Vn=\frac{m_e{V}_e}{m_n}=\frac{9.1\times 10^{-28}\times x}{1.674\times 10^{-24}}=\frac{x}{1840}$ .