SI units Flashcards
what are the international system of units?
7 base units of measurement which are dimensionally independent from which other units can be derived from
what are the 7 SI base units?
SMMACKK
second (s)
meter (m)
mole (mol)
ampere (A)
candela (Cd)
kilogram (Kg)
kelvin (K)
what is the base unit for length?
meter
what is the base unit for time?
second
what is the base unit for mass?
kilogram
what is the base unit for current?
ampere
what is the base unit for temperature?
kelvin
what is the base unit for amount of substance?
mole
what is candela a measurement of?
luminosity
what are the two supplementary units?
The plane angle (radian) and solid angle (steradian) were supplementary units
but this category was abolished in 1995. These units are considered named
derived units.
what is the derived units for volume, area and density?
volume - cubic meter - m^3
area - squared meter -m^2
density - kg per cubic meter- kg/m^3
what is the derived units for velocity and acceleration?
velocity - meters per second - m/s
accelaration - meters per second squared.
what is the derived units for force, pressure and energy?
force = Newtons = Kg.m.s-2
pressure = newtons per meter squared = kg·m–1·s–2
energy = joule = N.m = kg·m2
·s–2
what is the derived unit for power?
joules/ second
joules = N.m
N = kg.m.s-2
kg·m2 ·s–3
what is the derived units for electrical charge / coulombs?
A·s
what is the Electric potential
difference in derived units - volts?
volts = W/A
watts = J/s
J = N.m
N = kg.m.s-2
kg·m2·s–3·A–1
what is the derived SI unit for capacitance?
Current / volt
kg–1·m–2·s4·A2
define capacitance and 1 farad
Capacitance is the derived SI unit for ability for a device to store charge.
it is measured in farads.
where…
A capacitator with a capacitance of one farad will store one coulomb of charge when one volt is applied
state the derived SI unit for Electrical
resistance?
units = Ohms
V/A
kg·m2·s–3·A–2
what is tesla a measure of? what are its derived SI units?
magnetic flux density
Wb/m2
kg·s–2·A–1
Wb = V.s
what is weber (Wb) a measure of? what are its derived SI units?
magnetic flux
V.s
kg·m2·s–2·A–1
what is the unit for inductance and the SI derived units?
Henry (H)
Wb/A
kg·m2·s–2·A–2
what are the following multiples of?
deca, hecto, kilo, mega, giga, tera
deca = 10^1
hecto = 10^2
kilo = 10^3
mega = 10^6
giga = 10^9
tera = 10^12
what is the name of the following multiples…
10^15, 10^18, 10^21, 10^24
10^15 = pica
10^18 = exa
10^21 = zetta
10^24 = yotta
what is the name of the following multiples…
10^-1, 10^-2, 10^-3, 10^-6, 10^-9, 10^-12, 10^-15, 10^-18, 10^-21, 10^-24
10^-1 = deci
10^-2 = centi
10^-3 = milli
10^-6 = micro
10^-9 = nano
10^-12 = pico
10^-15 = femto
10^-18 = atto
10^-21 = zepto
10^-24 = yocto
what is a Sievert? what is this also called?
radiation dose per Kg
units = Sv = J/Kg
can also be called Gray for radiation absorbed - same derived SI units.
what are the different units for pressure and conversion factors compared to 1atm?
1 atmosphere
760mmHg
760 Torr
101326 pascal
1.01325 barr
14.7 psi = pounds per square inch
1020 cm3 of water
how is kelvin converted to degrees C?
K + 273.15
what is the SI derived unit for frequency?
measured in Hertz = S^-1
what is the derived SI for joules?
joules = work done
N.m
kg.m2.s-2
what volume does 1 mole of gas occupy?
22.4 litres
Kg is the base unit for what?
Mass
(not weight)
what is the difference between weight and mass?
weight is the force acting on a mass
i.e. depending on gravity this will change
what is the SI unit for volume?
M^3
Cubic meters
what is 1atm in 1bar?
1 atmosphere = 1.013 Bar.
what is SI unit for Newton?
kg m/s2
