\[\begin{aligned}
E&=hf\\
E&=\frac{hc}{\lambda}
\end{aligned}\]
Variables
Ephoton energy (J)
hPlanck constant (J·s)
ffrequency (Hz)
lambda[λ]wavelength (m)
cspeed of light (m/s)
Description
What is this formula?
The photon energy formula calculates the energy carried by a single photon of electromagnetic radiation. It is one of the fundamental equations of quantum physics and establishes that light energy is quantized.
When to use it
Use this formula when calculating photon energies from frequency or wavelength in optics, spectroscopy, lasers, astronomy, atomic physics, and quantum mechanics.
Example
Data:
Frequency:
f=6.0×10^14 Hz
Formula:
E=hf
Substitution:
E=(6.626×10^-34)(6.0×10^14)
Result:
E=3.98×10^-19 J
Applications
- Laser systems
- Quantum mechanics
- Spectroscopy
- Semiconductor physics
- Atomic transitions
- Astronomy