Question

. Estimate the velocity of neutrons needed for the study of neutron diffraction of crystal
structures if the interatomic spacing in the crystal is of the order of 2 Å. Also estimate the
kinetic energy of the neutrons corresponding to this velocity. Mass of neutron = 1.6749 x 10-
27 kg.

Answer 1

Estimate the velocity:

$$v=\frac h{m\lambda}=1978\text{ m/s}.$$

Estimate the kinetic energy:

$$E=\frac12mv^2=0.02\text{ eV}.$$