Freezing point of silver

The fixed points in the lTS-90 are given in Tabie 11.39. Platinum resistance thermometers are recommended for use between 14 K and 1235 K (the freezing point of silver), calibrated against the fixed points. Below 14 K either the vapor pressure of helium or a constant-volume gas thermometer is to be used. Above 1235 K radiometry is to be used in conjunction with the Planck radiation law,... 

Above 962°C, the freezing point of silver, temperatures on the ITS-90 ate defined by a thermodynamic function and an interpolation instmment is not specified. The interpolation instmment universally used is an optical pyrometer, manual or automatic, which is itself a thermodynamic device. 

Between the triple point of equilibrium hydrogen (13.8033 K) and the freezing point of silver (1234.93 K), Tgo is defined by means of platinum resistance thermometers calibrated at specific sets of defining fixed points. The temperatures are given in terms of the ratio of the resistance of the thermometer at temperature Tgo to the resistance at the triple point of water ... 

Above the freezing point of silver, Tgq is defined in terms of a defining fixed point and the Planck radiation law, and optical pyrometers are frequently used as temperature probes. The Comite Consultatif de Thermometrie gives a thorough discussion of the different techniques for approximation of the international temperature scale of 1990 [2, 4],... 

Above the freezing point of silver, T90 is defined by the relationship... 

Boiling point of liquid oxygen Boiling point of water Freezing point of zinc Freezing point of silver Freezing point of gold... 

Curve BC Similarly, B represents the melting point of pure silver. By the addition of lead to it, the freezing point of silver decreases along BC and we get a solution of it with lead. The curve BC is known as the freezing point or melting point curve of silver. The two phases present along it are solid silver and a solution of it with lead. It is, therefore, a univariant curve as,... 

Equilibrium between the solid and liquid phases of silver (freezing point of silver) 1,235.08 961.93... 

Range Above 1234.93 K. Above the freezing point of silver, an optical pyrometer is nsed to measnre the emitted radiant flux (radiant excitance per unit wavelength interval) of a blackbody at wavelength A. The defining equation is the Planck radiation law in the form... 

The majority of pulse calorimetric measurements use pyrometry, which is non-contact (optical) measurement of the thermal radiation emitted fi om any heated body or substance according to Planck s radiation law for black body radiation. Planck s law describes the spectral distribution of black body radiance which provides the basis for the International Temperature Scale (ITS-90) [76], especially above the freezing point of silver [77]. Because Planck s law is only... 

---