Eta (letter)

For other uses, see Eta .

In Modern Greek the letter is pronounced Close Front Unrounded Vowel . In the Classical version of the Ancient Greek language, it was pronounced as a long . The symbol was initially used to denote the Rough Breathing , Voiceless Glottal Fricative . In the Ionic Dialect , where this sound had disappeared by the sixth century BC, the letter was used to represent the long []. When the Ionic alphabet was adopted in Athens in 403 BC , [] (previously written as Ε) was also written as Η there too, hence the modern usage.

SYMBOL

Eta is sometimes used in place of Eng (ŋ) when eng is not available, because of their similar appearance.

The upper-case letter Η is used as a symbol for:

In Textual Criticism , the Alexandrian Text-type (from ''Hesychius'', its once-supposed editor).

In Chemistry , Enthalpy .

The lower-case letter η is used as a symbol for:

In Thermodynamics , the efficiency of a Carnot Heat Engine .

In Chemistry , the number of Electron s shared between a Metal center and a ligand in a Coordination Compound . For example, an Allyl Group can coordinate to Palladium in the η¹ mode or the η³ mode.

In Optics , the Refractive Index of an optical medium (although the letter ''n'' is more common).

In Particle Physics , to represent the η Baryon s.

In Statistics , ''η''² is the "partial regression coefficient".

In Astronomy , the seventh brightest (usually) star in a Constellation . ''See'' Bayer Designation .

In Experimental Particle Physics , η stands for Pseudorapidity .

In mathematics, η-conversion, see Lambda Calculus

In Fluid Dynamics , η stands for Viscosity .

Information About ™

Eta (letter)

Information About ^{^™}