SI Units Flashcards
What does s stand for?
Seconds
How do you define a second?
The duration of a certain number of oscillations of a caesium-133 atom
What does mol stand for?
Mole. This is the amount of substance that contains the same number of particles as there are atoms in 0.012 kg (12 g) of carbon-12
What does m stand for?
Metre
How is a metre measured?
Length traveled by light in a vacuum in 1/300 000 000 of a second
What does A stand for?
Ampere. It is a quantity related to electric current. The current in two parallel conductors of infinite length, placed 1 metre apart in a vacuum that would produce force of 2x10-7 N/m
What does cd stand for?
Candela. This is related to intensity of illumination. It is the measurement of luminous intensity of monochromatic light
What does K stand for?
Kelvin. This is a measure of thermodynamic temperature. It is the equivalent of -273 degrees centigrade.
What does Kg stand for?
Kilograms. This is the only SI unit related to mass.
What is the derived unit for measuring area?
Square metres
What is the derived unit for measuring volume?
Cubic metres
What is the derived unit for measuring speed?
Metres per second
What is the derived unit for measuring velocity?
Metres per second with direction
What is the derived unit for measuring acceleration?
Metres per second squared
What is the derived unit for measuring current density?
Ampere per square metre
What is the SI unit for pressure?
Pascal, Pa.
What are Newtons the product of?
Mass x acceleration (Kg x m/s^2)
The second is the time taken for light to travel a certain length in a vacuum T/F
False. A second is the duration of a certain number of oscillations of a caesium-133 atom. The description of the metre is based on light travelling in a vacuum.
The base unit for weight is the kilogram T/F
False. The kilogram is the base unit for Mass. Weight is not a base unit at all: it is force acting upon mass. Hence, people on the moon have less force, i.e. gravity, acting upon them so they weigh less, even though their mass is exactly the same.
The base unit for temperature is the Celsius T/F
False. The base unit for temperature is the Kelvin, which is Celsius minus 273.15.
The base unit for length is the metre T/F
True
The base unit for electrical current is the volt T/F
False. The base unit for electrical current is the Ampere.
Derived units must always be expressed as base units T/F
False. The Pascal, for example, can be expressed as base units (kg/m-1/s-2) or a combination of base and derived units (N/m2).
Velocity and speed have the same base units T/F
True. Speed is defined as m.s-1, Velocity is defined as m.s-1 but in a given direction.
101.3 kPa is equivalent to 760 cm H2O T/F
False. It is equivalent to 760 mmHg. It would be equivalent to 1020 cmH2O.
The litre is the SI unit for volume T/F
False. The cubic centimeter is the approved unit, with 1 cm3 being equivalent to 1ml.
The kilopascal is the SI unit for pressure T/F
True. Although the pascal is the actual unit, by using the approved kilo- prefix, it is still classed as an SI unit.
1 Bar is greater than 1 Atmosphere T/F
False. Although, for simplicity, both Bar and atmosphere are considered to have a value of 1, 1 atmosphere = 1.013 Bar.
An ETCO2 of 3.5 kPa is equivalent to 27 mmHg T/F
True
10 cmH2O is equivalent to 7.6 mmHg T/F
True
In base units, what does kg x m2/s2 represent?
Joule
In base units, what does kg x m/s2 represent?
Newton
In base units, what does kg/m/s2 represent?
Pascal
In base units, what does m/s represent?
Speed
In base units, what does kg x m2/s3/A2 represent?
Ohm
1 ATM = 1.013 Bar = 101.3 kPa = 760 mmHg = 1020 cmH20
Equivalences
