Wavelength ↔ Frequency Calculator
c = λ × ν. Wavelength in vacuum from frequency or vice versa. c = 3×10⁸ m/s.
Result
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How to use this calculator
- Pick direction.
- Enter freq or wavelength.
- Pick medium for refractive correction.
About this calculator
Speed of light c = λ × ν (frequency). Vacuum c ≈ 3 × 10⁸ m/s. In other media, c reduces by 1/n. Visible light: 380-750 nm wavelength = 4-7.9 × 10¹⁴ Hz frequency. Photon energy E = hν = 6.626 × 10⁻³⁴ × frequency. UV is more energetic per photon (~3-100 eV) — this is why it damages DNA. Radio waves: low energy (~ 10⁻⁹ eV per photon).
Frequently asked
Why c = λν?+
Distance per cycle = λ. Cycles per second = ν. Distance per second = wave speed = λ × ν. Universal.
Speed in water/glass?+
Slower: v = c/n. In glass (n=1.5): 2 × 10⁸ m/s (light is "slow" through glass).
Photon energy?+
E = hν. Higher freq = more energy per photon. UV-C (~5 eV) breaks DNA bonds; visible (~2 eV) doesn't.
5G frequency?+
Sub-6 GHz: ~3-6 GHz. mmWave: 24-40 GHz, very short wavelength (8-12 mm), needs many small cells.
Color from wavelength?+
Red ~700 nm, green ~550, blue ~450, violet ~400. Below 380 = UV (invisible). Above 750 = IR (invisible, felt as heat).
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