Difference between revisions of "Beer"
(→1. The classical law and its history) |
|||
| Line 4: | Line 4: | ||
| − | == 1. The classical law and its history == | + | <span style="font-family:Georgia;">== 1. The classical law and its history == |
| − | When electromagnetic radiation, such as ultraviolet or visible light, passes through a transparent medium that contains an absorber of that illumination, the radiation’s intensity diminishes steadily with passage through the medium. Commonly the radiation is in the form of a collimated beam that impinges perpendicularly on a slab of width L of the medium, as suggested diagrammatically in Figure 1.One may conjecture that, at any illuminated plane x within the medium, the decrease in the intensity I of the radiation with distance would be proportional to the uniform concentration c of the absorber and to the local intensity of the light at that point; that is | + | <span style="font-family:Georgia;"> When electromagnetic radiation, such as ultraviolet or visible light, passes through a transparent medium that contains an absorber of that illumination, the radiation’s intensity diminishes steadily with passage through the medium. Commonly the radiation is in the form of a collimated beam that impinges perpendicularly on a slab of width L of the medium, as suggested diagrammatically in Figure 1.One may conjecture that, at any illuminated plane x within the medium, the decrease in the intensity I of the radiation with distance would be proportional to the uniform concentration c of the absorber and to the local intensity of the light at that point; that is |
<math> | <math> | ||
\frac{\mathrm d}{\mathrm d x} ( I(x) )=-\alpha cI(x) (1) | \frac{\mathrm d}{\mathrm d x} ( I(x) )=-\alpha cI(x) (1) | ||
</math> | </math> | ||
Revision as of 22:10, 3 February 2017
== 1. The classical law and its history ==
When electromagnetic radiation, such as ultraviolet or visible light, passes through a transparent medium that contains an absorber of that illumination, the radiation’s intensity diminishes steadily with passage through the medium. Commonly the radiation is in the form of a collimated beam that impinges perpendicularly on a slab of width L of the medium, as suggested diagrammatically in Figure 1.One may conjecture that, at any illuminated plane x within the medium, the decrease in the intensity I of the radiation with distance would be proportional to the uniform concentration c of the absorber and to the local intensity of the light at that point; that is
[math] \frac{\mathrm d}{\mathrm d x} ( I(x) )=-\alpha cI(x) (1) [/math]
