Formula: De Broglie wavelength Mass Velocity
$$\lambda ~=~ \frac{h}{m \, v}$$
$$\lambda ~=~ \frac{h}{m \, v}$$
$$m ~=~ \frac{h}{v \, \lambda}$$
$$v ~=~ \frac{h}{m \, \lambda}$$
De Broglie wavelength
$$ \lambda $$ Unit $$ \mathrm{m} $$
Every particle of mass \(m\) (e.g. electron, proton) can be assigned a wavelength \( \lambda \) in quantum mechanics, the so-called matter wavelength (also called De-Broglie wavelength). De-Broglie wavelength determines the interference ability of particles.
Here \( m \, v \) is the momentum \(p\) of the particle.
Mass
$$ \class{brown}{m} $$ Unit $$ \mathrm{kg} $$
Mass of the particle. Heavy particles have a shorter matter wavelength than light particles.
Velocity
$$ \class{blue}{\boldsymbol v} $$ Unit $$ \frac{\mathrm m}{\mathrm s} $$
Velocity with which the considered particle moves. Fast particles have a shorter matter wavelength than slow particles.
Planck's Constant
$$ h $$ Unit $$ \mathrm{Js} $$
Planck's constant is a physical constant (of quantum mechanics) and has the value:
$$ h = 6.626 \, 070 \, 15 \,\cdot\, 10^{-34} \, \mathrm{Js} $$