Neutron diffraction by a crystal can be used to make a velocity selector for neutrons. Suppose the spacing between the relevant planes in the crystal is d = 0.20 nm. A beam of neutrons is incident at an angle θ = 10.0° with respect to the planes. The incident neutrons have speeds ranging from 0 to 2.0 × 104 m/s.
(a) What wavelength(s) are strongly reflected from these planes?
(b) For each of the wavelength(s), at what angle with respect to the incident beam do those neutrons emerge from the crystal?