Assertion: spectrophotometer | /r/Desires | prism
Facets:
value: to obtain different wavelengths
type: PURPOSE
Source sentences:
text: In addition to a light source (100 W light bulb or other polychromatic sources) and detector, a spectrophotometer also requires a prism or grating to obtain different wavelengths from the light source, and a slit to select a narrow range of wavelengths.