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Guidelines for Examination in the EPO
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1.1
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SI base units |
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Quantity |
Unit |
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Name |
Symbol |
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Length |
metre |
m |
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Mass |
kilogram |
kg |
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Time |
second |
s |
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Electric current |
ampere |
A |
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Thermodynamic temperature |
kelvin |
K |
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Amount of substance |
mole |
mol |
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Luminous intensity |
candela |
cd |
Definitions of SI base units:
- Unit of length
The metre is the length of the path travelled in a vacuum by light during 1/299792458 seconds.
- Unit of mass
The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.
- Unit of time
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.
- Unit of electric current
The ampere is that constant current which if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section and placed one metre apart in a vacuum, would produce between these conductors a force equal to 2 x 10-7 newton per metre of length.
- Unit of thermodynamic temperature
The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
- Unit of amount of substance
The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kg of carbon 12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles or specified groups of such particles.
- Unit of luminous intensity
The candela is the luminous intensity, in a given direction, of a source that emits monochromatic rays with a frequency of 540 x 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.
1.1.1 Special name and symbol of the SI unit of temperature for expressing Celsius temperature
