See: action spectrum, responsivity (in detection of radiation)
Sources:
PAC, 1995, 67, 1745. 'Nomenclature, symbols, units and their usage in spectrochemical analysis-XI. Detection of radiation (IUPAC Recommendations 1995)' on page 1749 (https://doi.org/10.1351/pac199567101745)
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2270 (https://doi.org/10.1351/pac199668122223)