Electromagnetic Wave Calculator (c = λf)
All electromagnetic waves travel at the speed of light (about 300 million m/s in vacuum), but they span a huge range of frequencies and wavelengths. Your WiFi router broadcasts at 2.4 GHz (12.5 cm wavelength), while visible red light oscillates at 430 trillion Hz (700 nm). This calculator converts between frequency and wavelength, finds photon energy, and identifies where a wave sits on the EM spectrum.
Core Formulas
Speed of Light Relation
c = lambda x f
The speed of light (c = 2.998 x 10 to the 8 m/s) is a constant. Increase frequency, and wavelength shrinks proportionally.
Photon Energy
E = hf = hc / lambda
Planck's constant h = 6.626 x 10 to the negative 34 J s. Higher frequency (shorter wavelength) means more energy per photon. This is why UV light causes sunburn but radio waves do not.
The Electromagnetic Spectrum
| Band | Frequency Range | Wavelength | Everyday Example |
|---|---|---|---|
| Radio | 3 kHz - 300 MHz | 1 km - 1 m | AM/FM radio |
| UHF | 300 MHz - 3 GHz | 1 m - 10 cm | TV, cell phones |
| Microwave | 3 GHz - 300 GHz | 10 cm - 1 mm | WiFi, microwave ovens |
| Infrared | 300 GHz - 430 THz | 1 mm - 700 nm | TV remotes, heat |
| Visible | 430 - 750 THz | 700 - 400 nm | Human vision |
| Ultraviolet | 750 THz - 30 PHz | 400 nm - 10 nm | Sunburn, sterilization |
| X-ray | 30 PHz - 30 EHz | 10 nm - 10 pm | Medical imaging |
| Gamma | > 30 EHz | < 10 pm | Nuclear reactions |
Common Frequencies
- AM radio: 540-1600 kHz (wavelengths of 187-556 m)
- FM radio: 88-108 MHz (2.8-3.4 m)
- WiFi 2.4 GHz: 12.5 cm wavelength
- WiFi 5 GHz: 6 cm wavelength
- 5G mmWave: 24-39 GHz (7.7-12.5 mm)
- Microwave oven: 2.45 GHz (same band as WiFi)