Concept Quiz

The Planck-Einstein Relation

Classical physics modeled light as a continuous wave. Max Planck and Albert Einstein revolutionized physics by proving that electromagnetic energy is quantized—emitted and absorbed in indivisible discrete "packets" called photons.

$$E = h \nu = \frac{h c}{\lambda}$$
E = Energy of a single photon (Joules or eV)
h = Planck's Constant ($6.626 \times 10^{-34} \text{ J}\cdot\text{s}$)
c = Speed of Light ($3.0 \times 10^8 \text{ m/s}$)
ฮฝ = Frequency (Hz)
ฮป = Wavelength (m or nm)

Note: Visual representation of wave packets is a pedagogical model. Wavelength shapes and speeds in the animation are exaggerated for visual clarity.