Physics Flashcards
Definitions
Absolute humidity
Mass of water vapour present in a sample of air at a given temp (kg/m^3)
Absolute zero
Temperature at which all motion stops including atoms. -273.15’C / 0K
Ampere
Measure of current, Coloumbs/second, amount of charge passing a point in unit time.
Current that produces a force of 2x10^-7 newtons per metre between two parallel wires of infinite length 1m apart in a vacuum.
Boiling point
Temperature at which the vapour of a liquid equals that of ambient pressure, causing a change from liquid to vapour
Calorie
Energy required to heat up the temperature of 1g of water by 1’C, 1 calorie = 4.16J
Candela
SI unit of luminous intensity. A candle emits roughly the light intensity of 1 candela.
Coulomb
Unit of charge, amount of charge passing a point of interest in 1 second when 1 ampere is flowing. Ampere/second.
Critical temperature
The temperature above which, a gas cannot be compressed into liquid no matter how much pressure is applied.
Freezing point
Temperature at which solid and liquid phases of a substance are in equilibrium at a given pressure.
Force
That which changes the state of rest or motion. Measured in Newtons.
1 N - force required to accelerate a mass of 1 Kg by 1m.s-2.
Mass x Acceleration
Gas
A state of matter existing between liquid and plasma.
A substance above its critical temperature, with its particles vastly separated as opposed to solids and liquids, and will fill any space available.
Heat capacity
Amount of heat energy required to increase the temperature of a substance by 1’C.
SI unit - Joules/Kelvin.
Hertz
SI unit of frequency. 1 cycle per second = 1hz.
Joule
SI unit for energy.
Energy expended when applying a force of 1 NEWTON through distance of 1METRE.
Newton . Metre
Watts . Second
Pa . m3
kg.m2.s-2
Kelvin
SI unit for temperature.
1K = 1/273.16’c of the triple point of water.
Kilogram
SI unit for mass.
Latent heat
Energy dissipated or absorbed when there is a shift in the state of matter at a particular temperature- no ‘actual’ change in temperature.
Latent heat of vaporisation
The amount of heat required to convert a mass of liquid at its boiling point into vapour without an increase in temperature under standard atmospheric pressure.
kg/mol.
Mol
SI unit - amount of a substance.
Quantity of atoms containing the same number of particles as of that contained in 12g of C-12. 6.0x10^23 particles - avogadros constant.
Newton
SI unit for force. kg.m.s-2
Ohm
SI unit for resistance. Resistance between two points of a conductor when constant potential difference of 1 volt is applied and produces 1 ampere of current.
Pascal
Unit of pressure.
N.M-2
Power
Rate of work (WATTS)
1 Watt = 1 Joule/second
Relative humidity
Percentage saturation of air with water as a ratio of that if the same air was maximally saturated with water at a given temperature.
Ratio of water vapour pressure to saturated vapour pressure.
