# Ratio of specific heats

(Difference between revisions)
 Revision as of 18:57, 13 August 2007 (view source)m (This was well written and informative. However to be truly of encyclopaedic quality references are needed)← Older edit Latest revision as of 20:03, 15 August 2007 (view source)Jasond (Talk | contribs) m Line 7: Line 7: The adiabatic index always exceeds unity; for a [[polytropic gas]] it is constant.{{fact}} For [[monatomic gas]] $\gamma=5/3$, and for [[diatomic gases]] $\gamma=7/5$, at ordinary [[temperatures]].{{fact}} For air its value is close to that of a diatomic gas, 7/5 = 1.4.{{fact}} The adiabatic index always exceeds unity; for a [[polytropic gas]] it is constant.{{fact}} For [[monatomic gas]] $\gamma=5/3$, and for [[diatomic gases]] $\gamma=7/5$, at ordinary [[temperatures]].{{fact}} For air its value is close to that of a diatomic gas, 7/5 = 1.4.{{fact}} - Sometimes $\kappa$ is used instead of $\gamma$ to denote the [[specific heat ratio]].{{fact}} + Sometimes $k$ or $\kappa$ is used instead of $\gamma$ to denote the specific heat ratio. {{Stub}} {{Stub}}

## Latest revision as of 20:03, 15 August 2007

The ratio of specific heats (also known as adiabatic index), usually denoted by $\gamma$, is the ratio of specific heat at constant pressure to the specific heat at constant volume.

$\gamma \equiv \frac{C_p}{C_v}$

The adiabatic index always exceeds unity; for a polytropic gas it is constant. For monatomic gas $\gamma=5/3$, and for diatomic gases $\gamma=7/5$, at ordinary temperatures. For air its value is close to that of a diatomic gas, 7/5 = 1.4.

Sometimes $k$ or $\kappa$ is used instead of $\gamma$ to denote the specific heat ratio.