Question

If the mass of neutron $=1.7\times {10}^{-27}kg$. then the De broglie wavelength of neutron of energy $3eV$ is :

• A. $1.6\times {10}^{-10}m$
• B. $1.6\times {10}^{-11}m$
• C. $1.4\times {10}^{-10}m$
• D. $1.4\times {10}^{-11}m$

Answer 1

Answer: (B)

$1.6\times {10}^{-11}m$

Given,

$m_e=1.7\times {10}^{-27}kg$

$E=3eV$

$e=1.6\times {10}^{-19}C$

De broglie wavelength of the neutron,

$\lambda =\frac{h}{P}=\frac{h}{\sqrt{2m_{e}E}}$

$\lambda =\frac{6.625\times {10}^{-34}}{\sqrt{2\times 1.7\times {10}^{-27}}\times 3\times 1.6\times {10}^{-19}}$

$\lambda =1.6\times {10}^{-11}m$

The correct option is B.