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British thermal unit (60 °F) BTU 60 °F: ≈ 1.054 68 × 10 3 J: British thermal unit (63 °F) BTU 63 °F: ≈ 1.0546 × 10 3 J: calorie (International Table) cal IT: ≡ 4.1868 J = 4.1868 J: calorie (mean) cal mean: 1 ⁄ 100 of the energy required to warm one gram of air-free water from 0 °C to 100 °C at a pressure of 1 atm ≈ 4.190 02 J ...
kT (also written as k B T) is the product of the Boltzmann constant, k (or k B), and the temperature, T.This product is used in physics as a scale factor for energy values in molecular-scale systems (sometimes it is used as a unit of energy), as the rates and frequencies of many processes and phenomena depend not on their energy alone, but on the ratio of that energy and kT, that is, on E ...
One square metre of the Earth receives about 1.4 kilojoules of solar radiation every second in full daylight. [20] A human in a sprint has approximately 3 kJ of kinetic energy, [21] while a cheetah in a 122 km/h (76 mph) sprint has approximately 20 kJ. [22] One watt-hour, of electricity or any other form of energy, is 3.6 kJ. megajoule
* Normal human body temperature is 36.8 °C ±0.7 °C, or 98.2 °F ±1.3 °F. The commonly given value 98.6 °F is simply the exact conversion of the nineteenth-century German standard of 37 °C. Since it does not list an acceptable range, it could therefore be said to have excess (invalid) precision.
Since 1982, STP has been defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 1 bar (100 kPa, 10 5 Pa). NIST uses a temperature of 20 °C (293.15 K, 68 °F) and an absolute pressure of 1 atm (14.696 psi, 101.325 kPa). [3] This standard is also called normal temperature and pressure (abbreviated as NTP).
Isotherms of an ideal gas for different temperatures. The curved lines are rectangular hyperbolae of the form y = a/x. They represent the relationship between pressure (on the vertical axis) and volume (on the horizontal axis) for an ideal gas at different temperatures: lines that are farther away from the origin (that is, lines that are nearer to the top right-hand corner of the diagram ...
Values are given in terms of temperature necessary to reach the specified pressure. Valid results within the quoted ranges from most equations are included in the table for comparison. A conversion factor is included into the original first coefficients of the equations to provide the pressure in pascals (CR2: 5.006, SMI: -0.875).
For example, both the old Celsius scale and Fahrenheit scale were originally based on the linear expansion of a narrow mercury column within a limited range of temperature, [4] each using different reference points and scale increments. Different empirical scales may not be compatible with each other, except for small regions of temperature ...