<P> In photometry, luminous intensity is a measure of the wavelength - weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye . The SI unit of luminous intensity is the candela (cd), an SI base unit . </P> <P> Photometry deals with the measurement of visible light as perceived by human eyes . The human eye can only see light in the visible spectrum and has different sensitivities to light of different wavelengths within the spectrum . When adapted for bright conditions (photopic vision), the eye is most sensitive to greenish - yellow light at 555 nm . Light with the same radiant intensity at other wavelengths has a lower luminous intensity . The curve which measures the response of the human eye to light is a defined standard, known as the luminosity function . This curve, denoted V (λ) or y _̄ (λ) (\ displaystyle \ textstyle (\ overline (y)) (\ lambda)), is based on an average of widely differing experimental data from scientists using different measurement techniques . For instance, the measured responses of the eye to violet light varied by a factor of ten . </P>

Write s.i unit of luminous intensity and temperature