SI units Flashcards
Define SI Units
Second:
Time: Duration of the given number of oscillations of caesium 133 atom
Metre:
Distance: Length of the path travelled by light in a vacuum during a certain fraction of a second
Mole:
substance: Substance that contains as many elementary particles as there are atoms in 0.012kg of carbon-12
Ampere:
Current: The current in two parallel conductors of infinite length and placed 1 metre apart in a vacuum which would produce between them a force of 2x10-7 N.m-1
Candela:
Luminous intensity: Luminous intensity in a given direction of a source that emits monochromatic light at a specific frequency
Kilogram:
Mass: Mass of international prototype in Sevres France
Kelvin:
Temperature: 1/273.16 of the thermodynamic temp of the triple point of water
Derived SI Units
Area: Square metre. m2
Volume: Cubic metre. m3
Speed: Metre per sec. m.s-1
Velocity: Metre per sec in given direction: m.s-1
Acceleration: Metre per sec squared: m.s-2
Wave number: reciprocal metre. m-1
Current density: Ampere per square metre. A.m2
Concentration: Mole per cubic metre. mole.m-3
Dervived SI units with special symbols
Frequency:
Hertz, Hz, s-1
Force:
Newton, N, kg.m.s-2
Pressure:
Pascal, Pa, N.m-2
Energy/work:
Joule, J, N.m
Power:
Watt, W, J.s-1
Electrical charge:
Coulomb, C, A.s
Potential Difference:
Volt, V, W/A
Capacitance:
Farad, F, C/V
Resistance:
Ohm, V/A
