Radiometric quantities
From WikiLectures
Radiometric quantities characterize the performance of the source or the amount of energy transferred to the irradiated bodies. In the event that a radiation source needs to be evaluated, we usually work with radiant flux and radiance. If it is necessary to evaluate radiation falling on a certain body or passing through a certain part of space, one usually works with irradiation.
| magnitude | symbol | unit | dimension | definition |
|---|---|---|---|---|
| radiance | Le | watt per steradian per square meter | W·sr−1m−2 | A measure of the radiance of a surface source, determined by the ratio of the radiance of a given surface of the source in the selected direction and the perpendicular projection of the surface in this direction: |
| luminosity | Ie | watt per steradian | W·sr−1 | It expresses the ability of a given approximately point source to radiate in the observed direction, it is determined by the proportion of the elementary radiant flux and the elementary spatial angle in which this flux is emitted: |
| radiant flow | Φe | watt | W | It expresses the power transmitted by radiation, i.e. it is the amount of radiated energy related to a very short time interval (i.e. the derivative with respect to time). |
| irradiation | Ee | watt per square meter | W·m−2 | Expresses the power falling on the surface: |
| radiant energy | Q, We | joule | J = m2·kg·s−1 | It means energy transmitted by electromagnetic radiation (flow of photons) or matter radiation (flow of matter particles, e.g. electrons, neutrons, etc.) |
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References[edit | edit source]
- BINKO, Jaroslav. Fyzikální a technické veličiny. 1. edition. Nakladatelství technické literatury, 1968.
