{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"wavelength-frequency"},"result":{"entity_type":"calculator","id":"wavelength-frequency","calculator_id":"wavelength-frequency","canonical_url":"https://tttkmbb.com/physics/wavelength-frequency","name":"Wavelength & Frequency Calculator","title":"Wavelength Frequency Calculator – λ = v / f for Light, Radio and Sound, with Photon Energy","category":"physics","category_name":"Physics","tool_name":"convert_wavelength_frequency","featured_mcp_tool":false,"description":"Converts between wavelength and frequency for a wave of known propagation speed (default: the speed of light in vacuum) and, for electromagnetic waves in vacuum, reports the photon energy E = h·f in joules and electronvolts.","use_when":"You know either the wavelength or the frequency of a light, radio or sound wave and need the other, or you need the photon energy of light of a given wavelength.","do_not_use_when":"The wave travels in a dispersive medium (glass, water) unless you supply the correct phase speed, or you need Doppler shifts or refraction.","inputs":[{"name":"wavelength_m","label":"Wavelength","type":"number","unit":"m","required":false,"exclusive_min":0,"description":"Wavelength in metres (1 nm = 1e-9 m, so 500 nm = 5e-7). Give either wavelength_m or frequency_hz.","example":5e-7},{"name":"frequency_hz","label":"Frequency","type":"number","unit":"Hz","required":false,"exclusive_min":0,"description":"Frequency in hertz (1 MHz = 1e6 Hz, 1 GHz = 1e9 Hz). Give either wavelength_m or frequency_hz."},{"name":"wave_speed_m_s","label":"Wave speed","type":"number","unit":"m/s","required":false,"default":299792458,"max":299792458,"exclusive_min":0,"description":"Propagation speed in the medium. Default c = 299,792,458 m/s (light in vacuum); use about 343 for sound in air at 20 °C, 1480 for sound in water.","example":299792458}],"outputs":[{"name":"solved_for","label":"Solved for","type":"string","decimals":4,"description":"Which quantity was computed: wavelength_m or frequency_hz."},{"name":"wavelength_m","label":"Wavelength","type":"number","unit":"m","decimals":12,"description":"λ = v / f."},{"name":"wavelength_nm","label":"Wavelength","type":"number","unit":"nm","decimals":4,"description":"Wavelength in nanometres (visible light ≈ 380–750 nm)."},{"name":"frequency_hz","label":"Frequency","type":"number","unit":"Hz","decimals":4,"description":"f = v / λ."},{"name":"wave_speed_m_s","label":"Wave speed","type":"number","unit":"m/s","decimals":4,"description":"Propagation speed used."},{"name":"photon_energy_ev","label":"Photon energy","type":"number","unit":"eV","decimals":6,"description":"E = h × f in electronvolts (only for electromagnetic waves in vacuum, i.e. wave_speed_m_s = c)."},{"name":"photon_energy_j","label":"Photon energy","type":"string","unit":"J","decimals":4,"description":"Photon energy in joules as a scientific-notation string with 5 significant figures, e.g. \"3.9729e-19\" (only when wave_speed_m_s = c)."}],"input_schema":{"type":"object","properties":{"wavelength_m":{"description":"Wavelength in metres (1 nm = 1e-9 m, so 500 nm = 5e-7). Give either wavelength_m or frequency_hz. Unit: m.","type":"number","exclusiveMinimum":0,"examples":[5e-7],"x-unit":"m"},"frequency_hz":{"description":"Frequency in hertz (1 MHz = 1e6 Hz, 1 GHz = 1e9 Hz). Give either wavelength_m or frequency_hz. Unit: Hz.","type":"number","exclusiveMinimum":0,"x-unit":"Hz"},"wave_speed_m_s":{"description":"Propagation speed in the medium. Default c = 299,792,458 m/s (light in vacuum); use about 343 for sound in air at 20 °C, 1480 for sound in water. Unit: m/s.","type":"number","maximum":299792458,"exclusiveMinimum":0,"default":299792458,"examples":[299792458],"x-unit":"m/s"}},"additionalProperties":false},"output_schema":{"type":"object","properties":{"solved_for":{"description":"Which quantity was computed: wavelength_m or frequency_hz.","type":"string"},"wavelength_m":{"description":"λ = v / f. Unit: m.","type":"number","x-unit":"m"},"wavelength_nm":{"description":"Wavelength in nanometres (visible light ≈ 380–750 nm). Unit: nm.","type":"number","x-unit":"nm"},"frequency_hz":{"description":"f = v / λ. Unit: Hz.","type":"number","x-unit":"Hz"},"wave_speed_m_s":{"description":"Propagation speed used. Unit: m/s.","type":"number","x-unit":"m/s"},"photon_energy_ev":{"description":"E = h × f in electronvolts (only for electromagnetic waves in vacuum, i.e. wave_speed_m_s = c). Unit: eV.","type":"number","x-unit":"eV"},"photon_energy_j":{"description":"Photon energy in joules as a scientific-notation string with 5 significant figures, e.g. \"3.9729e-19\" (only when wave_speed_m_s = c). Unit: J.","type":"string","x-unit":"J"}}},"formula":"wavelength_m = wave_speed_m_s / frequency_hz; frequency_hz = wave_speed_m_s / wavelength_m; photon_energy_j = h × frequency_hz with h = 6.62607015e-34 J·s; photon_energy_ev = photon_energy_j / 1.602176634e-19","sources":[{"name":"Wikipedia – Wavelength","url":"https://en.wikipedia.org/wiki/Wavelength","type":"reference","retrieved_at":"2026-09-23"},{"name":"Wikipedia – Photon energy","url":"https://en.wikipedia.org/wiki/Photon_energy","type":"reference","retrieved_at":"2026-09-23"},{"name":"NIST CODATA 2018 – Fundamental Physical Constants","url":"https://physics.nist.gov/cuu/Constants/","type":"standard","retrieved_at":"2026-09-23"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"Green light, 500 nm in vacuum","inputs":{"wavelength_m":5e-7},"expected":{"solved_for":"frequency_hz","frequency_hz":599584916000000,"wavelength_nm":500,"photon_energy_ev":2.479684,"photon_energy_j":"3.9729e-19"},"url":"https://tttkmbb.com/api/v1/calculate/wavelength-frequency?wavelength_m=5e-7"},{"name":"440 Hz sound in air (343 m/s)","inputs":{"frequency_hz":440,"wave_speed_m_s":343},"expected":{"solved_for":"wavelength_m","wavelength_m":0.779545,"wavelength_nm":779545454.5455},"url":"https://tttkmbb.com/api/v1/calculate/wavelength-frequency?frequency_hz=440&wave_speed_m_s=343"}],"faq":[{"q":"Why is there no photon energy for my sound wave?","a":"Photon energy E = h·f applies to electromagnetic radiation only; it is reported when the wave speed equals c (vacuum). Sound is a mechanical wave."},{"q":"What speed should I use for light in glass or water?","a":"c divided by the refractive index (about 1.5 for glass, 1.33 for water); the frequency stays the same while the wavelength shortens."}],"tags":["wavelength","frequency","photon energy","speed of light","hertz","nanometres"],"related":[{"calculator_id":"pendulum","reason":"Another periodic system: period and frequency of a pendulum."},{"calculator_id":"frequency","reason":"Convert frequencies between Hz, kHz, MHz and GHz."}],"links":{"html":"https://tttkmbb.com/physics/wavelength-frequency","markdown":"https://tttkmbb.com/physics/wavelength-frequency.md","json":"https://tttkmbb.com/physics/wavelength-frequency.json","api":"https://tttkmbb.com/api/v1/calculate/wavelength-frequency","schema":"https://tttkmbb.com/api/v1/calculators/wavelength-frequency","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-23"},"timestamp":"2026-09-23T23:27:44Z"}