A 0.22-calibre handgun fires a 25 g bullet at a velocity of 700 m s−1. Calculate the de Broglie wavelength of the bullet. Is the wave nature of matter significant for bullets?

Answer 1

λ = h / mv

λ = wavelength in meters = ?

h = Plancks constant = 6.626x10^-34 Js

m = mass in kg = 25 g x 1 kg / 1000 g = 0.025 kg

v = velocity in meters/sec = 700 m/s

λ = 6.626x10^-34 Js / (0.025 kg)(700 m/s) and recall that J can be expressed as kgm²/s²

λ = (6.626x10^-34 s-kg-m²/s²) / (0.025 kg)(700 m/s)

λ = 3.79x10^-35 m

Not sure how to answer if this is significant regarding the wave nature. Would guess not since it is so short as not to ever be observable, but then again such short λ would have a large energy. So, I don't know the answer to the 2nd part. Maybe a physicist will chime in. My answer would be "no".