Convert between wavelength, frequency, and photon energy with high precision (CODATA 2018 constants). Visualize the electromagnetic spectrum and identify spectral bands — essential for optics, astronomy, remote sensing, and quantum physics.
Electromagnetic radiation exhibits wave-particle duality. The conversion between wavelength (λ), frequency (ν), and photon energy (E) is governed by two fundamental equations:
where c is the speed of light in vacuum and h is Planck's constant. This calculator uses the 2018 CODATA internationally recommended values, ensuring traceable accuracy for scientific, academic, and engineering applications.
Given any input (wavelength, frequency, or energy), the calculator converts the quantity to SI base units (meters for λ, Hz for ν, J for E), then recomputes the other two via λ = c/ν, ν = c/λ, and E = hν. The wavenumber (in cm⁻¹) is derived as σ = 1/λ (with λ in cm). Angular frequency ω = 2πν. All round-trip conversions maintain numerical consistency within floating‑point precision.
Astronomers analyse redshifted Balmer lines (e.g., Hα at rest 656.28 nm) to determine galaxy recession velocities. Using the Doppler shift formula: Δλ/λ = v/c. Our calculator helps convert wavelength shifts into energy or frequency changes, supporting research on cosmic expansion. The built‑in H‑alpha example (656.28 nm) provides a benchmark: energy ≈ 1.889 eV. Understanding these fundamentals enables precise photometry and spectrographic calibration.
| Band | Wavelength Range | Frequency Range | Applications |
|---|---|---|---|
| Gamma rays | < 0.01 nm | > 30 EHz | Nuclear medicine, astrophysics |
| X-rays | 0.01 – 10 nm | 30 PHz – 30 EHz | Medical imaging, crystallography |
| Ultraviolet (UV) | 10 – 380 nm | 790 THz – 30 PHz | Sterilization, fluorescence |
| Visible | 380 – 750 nm | 400 – 790 THz | Human vision, colorimetry |
| Infrared (IR) | 0.75 – 300 µm | 1 – 400 THz | Thermal imaging, spectroscopy |
| Microwave | 1 mm – 1 m | 300 MHz – 300 GHz | Radar, communications |
| Radio waves | > 1 m | < 300 MHz | Broadcasting, astronomy |
For chemists and physicists, working in electronvolts (eV) and nanometers (nm) is ubiquitous. The product hc = 1239.841984 eV·nm (rounded) provides a simple conversion: E(eV) = 1239.841984 / λ(nm). Our calculator uses the exact constants to avoid rounding errors, delivering reliability for high‑precision spectroscopy tasks. All results are traceable to SI definitions.