Noun

(head)

* {{quote-book

, year = 2003 , title = Islam: Questions and Answers - Schools of Thought, Religions and Sects , author = Muhammad Saed Abdul-Rahman , quotee = Sheikh Muhammed Salih Al-Munajjid , volume = 8 , publisher = MSA Publication Limited , isbn = 9781861792914 , page = 89 , passage = The athiest(SIC) is destined to Hell fire in the Hereafter. This is because the athiest refuses the most basic belief which is the existance and oneness of Allaah. , pageurl = http://books.google.com/books?id=xcPwGmYwCKUC&pg=PA89 }}

Noun

(en noun)

(physics) Flux (of radiation).

* 1984-7 , John E. Kaufman, Jack F. Christensen, (Illuminating Engineering Society of North America), IES lighting handbook: Volume 1984 :

The entire east sky provided an equivalent exitance of 19 kilolumens per square meter (Method 1)

* 1998 , Glenn D. Boreman, Basic electro-optics for electrical engineers , page 49:

For a given temperature, exitance' is a function of wavelength. This results in a family of spectral '''exitance''' curves dependent on temperature. The equation for spectral ' exitance is the Planck equation:

* 1999 , Joseph Caniou, Passive infrared detection: theory and applications , page 42:

In practice, unless otherwise indicated, it is accepted that exitance is taken to be a hemispherical quantity.

* 2006 , Craig M. Payne, Principles of Naval Weapon Systems , page 104:

Exitance is the amount of power per unit area expressed in watts per square meter (w/m2), or square centimeter (w/cm2), that leaves a surface and is radiated into a hemisphere.