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Luminous energy: Q v [nb 3] lumen second: lm⋅s T⋅J: The lumen second is sometimes called the talbot. Luminous flux, luminous power Φ v [nb 3] lumen (= candela steradian) lm (= cd⋅sr) J: Luminous energy per unit time Luminous intensity: I v: candela (= lumen per steradian) cd (= lm/sr) J: Luminous flux per unit solid angle: Luminance: L v ...
Here is the wavelength of light, and ¯ is the luminous efficiency function, which represents the eye's sensitivity to different wavelengths of light. Luminous energy is the integrated luminous flux in a given period of time: Q v = ∫ 0 T Φ v ( t ) d t {\displaystyle Q_{\mathrm {v} }=\int _{0}^{T}{\mathit {\Phi _{\mathrm {v} }}}(t)\,\mathrm ...
This power is not a measure of the amount of light output, but rather indicates how much energy the bulb will use. Because incandescent bulbs sold for "general service" all have fairly similar characteristics (same spectral power distribution), power consumption provides a rough guide to the light output of incandescent bulbs.
Spectral sensitivity is the relative efficiency of detection, of light or other signal, as a function of the frequency or wavelength of the signal. In visual neuroscience , spectral sensitivity is used to describe the different characteristics of the photopigments in the rod cells and cone cells in the retina of the eye .
People with protanopia have essentially no sensitivity to light of wavelengths more than 670 nm. Most non-primate mammals have the same luminous efficiency function as people with protanopia. Their insensitivity to long-wavelength red light makes it possible to use such illumination while studying the nocturnal life of animals. [18]
By recording the attenuation of light for various wavelengths, an absorption spectrum can be obtained. In physics , absorption of electromagnetic radiation is how matter (typically electrons bound in atoms ) takes up a photon 's energy —and so transforms electromagnetic energy into internal energy of the absorber (for example, thermal energy ).
Light sensitivity or photosensitivity refers to a notable or increased reactivity to light. Apart from vision , human beings have many physiological and psychological responses to light. In rare individuals an atypical response may result in serious discomfort, disease, or injury.
Luminosity is an absolute measure of radiated electromagnetic energy per unit time, and is synonymous with the radiant power emitted by a light-emitting object. [1] [2] In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical objects. [3] [4]