British Thermal Units to Kiloelectronvolts (BTU to keV)
1 British thermal unit equals 6.585140678×10¹⁸ kiloelectronvolts (rounded).
How to convert British thermal units to kiloelectronvolts
To convert British thermal units to kiloelectronvolts, multiply the number of British thermal units by 6.585140678×10¹⁸. The factor is rounded to 10 significant digits. To go the other way, multiply kiloelectronvolts by 1.518570443×10⁻¹⁹ (rounded).
kiloelectronvolts = British thermal units × 6.585140678×10¹⁸
Example: 10 British thermal units = 6.585140678×10¹⁹ kiloelectronvolts.
The 'calorie' on food labels is really a kilocalorie. The thermochemical calorie (4.184 J) is used here unless marked IT.
About these units
British Thermal Unit (BTU)
The International Table BTU, exactly 1,055.05585262 joules. The energy to heat one pound of water by one degree Fahrenheit; used for heating, cooling and gas appliances in the US.
Few energy units come in as many versions as the British thermal unit. It was defined as the heat needed to raise one pound of liquid water by one degree Fahrenheit, but because water's heat capacity shifts slightly with temperature, definitions differ by up to 0.5 percent: about 1,054.35 J for the thermochemical Btu, 1,054.80 J at 59 degrees Fahrenheit (used for American natural gas pricing), 1,054.68 J at 60 degrees (mainly Canadian), and 1,059.67 J at 39 degrees. A 1942 note suggests the term apparently arose in the United States and was later adopted in Britain.
The version on this site is the International Table Btu, about 1,055.06 J, which comes from the international steam table conferences that tied heat units to the joule. Joule's own 1850 experiments gave 772.692 foot-pounds of work per Btu, the number that first linked heat to mechanical effort.
Today the Btu survives in natural gas pricing (MMBtu means a million Btu), US building energy reporting, and equipment ratings in Btu per hour. One ton of air-conditioning is 12,000 Btu/h, or 3.52 kW. A single wooden kitchen match burning releases about one Btu.
1 British thermal unit = 1,055.055853 joules (approximately).
Sources: Wikipedia: British thermal unit; Wikipedia: James Prescott Joule
Kiloelectronvolt (keV)
1,000 electronvolts. X-ray photon energies are in this range.
X-rays are the usual home of the keV. Wilhelm Roentgen discovered them on 8 November 1895, and their photon energies span about 100 eV to 100 keV. Photons above roughly 5 to 10 keV count as hard X-rays, while lower ones are soft. Medical diagnostic tubes run at 20 to 150 kilovolts, which sets the highest photon energies of a radiograph at about 20 to 150 keV. One keV is 1.602176634 x 10^-16 J.
Fusion research uses it for temperature. A magnetic confinement plasma at about 15 keV corresponds to roughly 174 million kelvin. Compared with the electronvolt, a kiloelectronvolt is a thousand times larger, so it lies well above the 1 to 10 eV of chemical bonds, yet far below the millions of electronvolts released in nuclear reactions.
1 kiloelectronvolt = 1.602176634×10⁻¹⁶ joules (exactly).
Sources: Wikipedia: X-ray; Wikipedia: Electronvolt
Related conversions
- Kiloelectronvolts to British thermal units (reverse)
- British thermal units to joules
- British thermal units to kilojoules
- British thermal units to watt-hours
- British thermal units to kilowatt-hours
- British thermal units to calories
- British thermal units to kilocalories
- British thermal units to megajoules
- British thermal units to gigajoules
- British thermal units to megawatt-hours
- British thermal units to foot-pounds
- British thermal units to millijoules
- British thermal units to electronvolts
- Joules to kiloelectronvolts
- Kilojoules to kiloelectronvolts
- Watt-hours to kiloelectronvolts
- Kilowatt-hours to kiloelectronvolts
- Calories to kiloelectronvolts
- Kilocalories to kiloelectronvolts
See all energy units.