Science & Physics Converters
Twenty-five converters for advanced physical quantities: viscosity, thermal properties, entropy, momentum, radiation, photometry, molarity, and more. Used in laboratory work, research, and engineering.
Mechanics & Thermodynamics
Waves, Radiation, Photometry
- Wavelength Converterm ↔ nm ↔ Å
- Photon Energy ConvertereV ↔ J
- Radioactivity ConverterBq ↔ Ci
- Radiation Dose ConverterGy ↔ rad ↔ Sv
- Radiation Exposure ConverterC/kg ↔ R
- Sound Level ConverterdB SPL ↔ Pa
- Illuminance Converterlux ↔ foot-candle
- Luminous Flux Converterlumen
- Luminous Intensity Convertercandela
- Optical Power Converterdiopter
Notes on Advanced Units
Many units in this category are unusual because they either lack decimal prefixes, come from historical measurement systems, or measure quantities that are themselves defined via several other quantities. The converter pages explain the assumptions and definitions for each.
Radiation quantities
Radiation is measured with three different but related quantities:
- Activity (Bq, Ci) — decays per second. 1 Bq = 1 decay per second. 1 Ci = 3.7 × 10¹⁰ Bq exactly.
- Absorbed dose (Gy, rad) — energy deposited per unit mass. 1 Gy = 1 J/kg. 1 rad = 0.01 Gy exactly.
- Equivalent dose (Sv, rem) — absorbed dose weighted by radiation type. 1 Sv = 1 J/kg for X-rays and gamma rays. 1 rem = 0.01 Sv exactly.
These three quantities measure different things and are not interchangeable. Always verify which is being used in a specific context.