Physics 5 — Modern Physics

Matter waves

continues from lesson 2 — values defined earlier in the course stay live here

ELI5: de Broglie's beautiful heresy — if waves can act like particles, then particles act like waves, with wavelength λ = h/(m·v). For everyday objects λ is laughably tiny, but for an electron it's atom-sized, which is exactly why electron microscopes see what light never could.

m_{e} = 9.109 \cdot 10^{-31}

electron mass (kg)

v_{e} = 2000000

a typical microscope beam (m/s)

\lambda_{e} = \frac{h_{p}}{m_{e} \cdot v_{e}}

3.6371 \times 10^{-10}

~0.36 nm — finer than any light

Real-world hook: matter waves are why electron microscopes resolve viruses and atoms, and the reason electrons fill atoms in shells (only whole wavelengths "fit") — the basis of the whole periodic table.