# Similar to electron diffraction, neutron diffraction microscope is also used for the determination of the structure of molecules.

Question:

Similar to electron diffraction, neutron diffraction microscope is also used for the determination of the structure of molecules. If the wavelength used here is 800 pm, calculate the characteristic velocity associated with the neutron.

Solution:

From de Broglie's equation,

$\lambda=\frac{\mathrm{h}}{m v}$

$v=\frac{\mathrm{h}}{m \lambda}$

Where,

$v=$ velocity of particle (neutron)

$h=$ Planck's constant

$m=$ mass of particle (neutron)

$\lambda=$ wavelength

Substituting the values in the expression of velocity (v),

$v=\frac{6.626 \times 10^{-34} \mathrm{JS}}{\left(1.67493 \times 10^{-27} \mathrm{~kg}\right)\left(800 \times 10^{-12} \mathrm{~m}\right)}$

$=4.94 \times 10^{2} \mathrm{~ms}^{-1}$

$v=494 \mathrm{~ms}^{-1}$

$\therefore$ Velocity associated with the neutron $=494 \mathrm{~ms}^{-1}$