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Number of Results: 6 Search : kelvin

kelvin (K) kelvin (#) Fr.: kelvin The basic unit of thermodynamic temperature in the international system of units
(→ Named after the Scottish physicist William Thomson, also known as Lord Kelvin (1824-1907), one of the most influential scientists of the 19th century. |

Kelvin scale marpel-e Kelvin Fr.: échelle de Kelvin A temperature scale, redefined in 1954, in which the zero point is equivalent to
-273.16 °C. This fundamental fixed point, based on
the → → |

Kelvin's postulate farâvas-e Kelvin Fr.: postulat de Kelvin A transformation whose only final result is to transform into work
heat extracted from a source which is at the same temperature is
impossible. Kelvin's postulate is a statement of
the → |

Kelvin-Helmholtz contraction terengeš-e Kelvin-Helmholtz Fr.: contraction de Kelvin-Helmholtz The contraction of a volume of gas under its → After the Scottish physicist William Thomson, also known as Lord Kelvin (1824-1907)
and the German physicist and physician Hermann Ludwig Ferdinand von Helmholtz (1821-1894),
who made important contributions to the thermodynamics of gaseous systems;
→ |

Kelvin-Helmholtz instability nâpâydâri-ye Kelvin-Helmholtz (#) Fr.: instabilité de Kelvin-Helmholtz An → |

Kelvin-Helmholtz time zamân-e Kelvin-Helmholtz Fr.: échelle de temps de Kelvin-Helmholtz The characteristic time that would be required for a contracting spherical cloud of gas
to transform all its → G is
the → gravitational constant, M is the mass of the
cloud, R the initial radius, and L the → luminosity.
The Kelvin-Helmholtz time scale determines how quickly a pre-main sequence star contracts
before → nuclear fusion starts.
For the Sun it is 3 x 10^{7} years, which also represents the time scale on which
the Sun would contract if its nuclear source were turned off. Moreover, this
time scale indicates that the gravitational energy cannot account for the
solar luminosity. For a → massive star of M = 30 Msun,
the Kelvin-Helmholtz time is only about 3 x 10^{4} years. |