(5-4) Using the de Broglie equation, if Cormorant’s wavelength is 20 cm, his momentum would then have to be:
p = h / λ = 6.626 x 10-34 / 0.20 = 3.3 x 10-33 kgms-1
So he would have to fly with a velocity, v = p / m = 3.3 x 10-33 / 2.5 = 1.3 x 10-33 ms-1.
The distance he would then have managed to fly in the entire lifetime of the universe to date is therefore:
Distance = speed x time = 1.3 x 10-33 x 4.3 x 1017 = 5.6 x 10-16 m
This means that in order to have a reasonable expectation of being diffracted, Cormorant’s velocity would have to be so small that he would cover a distance of around one millionth of the width of a hydrogen atom during the lifetime of the universe. That’s quite slow.