Question

Similar to electron diffraction, a 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.

Answer 1

From de Broglie's equation,
λ =$\frac{h}{mv}$
v = $\frac{h}{mv}$
Where, v = velocity of particle (neutron)
h = Planck's constant
m = mass of particle (neutron)
λ = wavelength
Substituting the values in the expression of velocity (v),
v = $\frac{6.626 × 10 ^{-34} Js}{ (1.67493 × 10 - 27 kg)(800 × 10^{ -12} m)}$
= 4.94 × 10 2ms-1
v= 494 ms-1
∴ Velocity associated with the neutron = 494 ms-1