Radiant power transmitted

Laws of Photometry. The time rate at which energy is transported in a beam of radiant energy is denoted by the symbol To for the incident beam, and by P for the quantity remaining unabsorbed after passage through a sample or container. The ratio of radiant power transmitted by the sample to the radiant power incident on the sample is the transmittance T ... 

Transmittance (T) Ratio of radiant power transmitted by sample to radiant power incident to it Absorbance (A) Logarithm to the base 10 of the reciprocal of the transmittance Absorptivity (a) Ratio of the absorbance to the product of the concentration and the length of the optical path. (If only one cell is used for all the work, the path length will be constant and can be left out of all ealens without introducing an e rror. To simplify the ealen, all measurements were made with the same 0.209mm cell. Hence, all the absorptivities were referred to a 0.209mm [ basis)... 

A= Absorbance = logj0l/T(T is Transmittance - ratio of radiant power transmitted by sample to radiant power incident to it) and a a -Mean Absorptivity of above compound... 

Band intensities are expressed as either transmittance (T) or absorbance (A). Transmittance is the ratio of the radiant power transmitted by a sample to the radiant power incident on the sample. Absorbance is the base 10 logarithm of the reciprocals of the transmittance A = logi0T. Quantitative measurements in the infrared usually begin with Beer s law and its analogs ... 

Transmitted radiant Radiant power transmitted by Transmitted intensity, I... 

Figure 24-18 Deviation from Beer s law caused by various levels of stray light. Note that absorbance begins to level off with concentration at high stray light levels. Stray light always limits the maximum absorbance that can be obtained because when the absorbance is high, the radiant power transmitted through the sample can become comparable to or lower than the stray light level.

To obtain spectroscopic information, the radiant power transmitted, fluoresced, or emitted must be detected in some manner and converted into a measurable quantity. A detector is a device that indicates the existence of some physical phenomenon. Familiar examples of detectors include photographic film (for indicating the presence of electromagnetic or radioactive radiation), the pointer of a balance (for indicating mass differences), and the mercury level in a thermometer (for indicating temperature). The human eye is also a detector it converts visible radiation into an electrical signal that is passed to the brain via a chain of neurons in the optic nerve and produces vision. 

Transmitted radiant power. P Radiant power transmitted by sample Transmitted inlensily. /... 

The term atomic absorption refers to the absorption of energy from a light source, with a consequent decrease in the radiant power transmitted through the flame. Measurement of this absorption corresponds to atomic absorption spectroscopy. 

Ratio of radiant power transmitted by a sample to the radiant power incident on the sample Distance between two points on adjacent waves that are in phase... 

Transmission, or the conduction of radiant energy through a medium, is characterized by transmittance, which is the ratio of radiant power transmitted by a material to the incident radiant power. Transmittance over a wide range of optical wavelengths is one of the optical characteristics of diamond. 

The ratio of the radiant power transmitted by the sample to that incident upon it T = I/Io- We shall commonly be speaking of relative transmittance. 

P = the radiant power transmitted by the sample— the transmitted radiation 303... 

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