Physics - Definitions Flashcards
Define heat capacity
It is the amount of heat required to raise temperature of a substance by 1°C.
Unit: J/K
Define heat.
Heat is a form of energy that can be transferred from hotter substance to a colder substance, the energy being in the form of kinetic energy of the molecules of the substance.
Define diffusion.
Movement of substance from an area of higher concentration to lower concentration, resulting from spontaneous movement of its constituent particles.
Osmosis
Migration of solvents from solution of lower concentration to higher concentration when they are separated by a semi permeable membrane.
State Henry’s law.
At a particular temperature, the amount of a given gas dissolved in a given liquid is directly proportional to partial pressure of the gas in equilibrium with the liquid.
It describes the mechanism of narcosis by Nitrogen, Oxygen etc. gases.
All gases have narcosis potency except Helium hence used as heliox during diving.
Humidity
Amount of water vapor present in a gas or in the atmosphere.
Absolute humidity
It is the mass of water vapor present in a given volume of air.
Expressed as gm/m3 or mg/Litre
Relative humidity
It is the ratio of mass of water vapor present in a given volume of air and mass required to saturate that given volume of air at the same temperature.
RH= Mp/Ms
Define Temperature
Temperature is the thermal state of a substance which determines wheter it will give heat to another substance or receive heat from it, heat being transferred from substance at the higher temperature to the lower temperature.
Define solubility
Extent to which a substance dissolves in another substance.
Dalton’s law
In a mixture of gases, the pressure exerted by each gas is the same as that as it would exert if it alone occupied the container.
By John Dalton
In 1891
Charles’ law
At constant pressure,
the volume of a given mass of gas varies directly with absolute temperature.
By Tachques Charles
In 1787
Boyle’s law
At constant temperature,
volume of a given mass of gas varies inversely with the absolute pressure.
By Robert Boyle
In 1662
Exponential
At a given time, the rate of change quality of a process is proportional to quantity of that process.
Flow
Flow is defined as the quantity of a fluid passing a point in unit time.
F= Q/t
Force
Force is that which changes or tends to change the state of rest or motion of an object
SI unit: Newton
1 Newton is the force that will give a mass of 1 kg acceleration of 1 m/s2
Pressure
It is the force applied or distributed over a surface or area.
P= f/a
SI Unit: Pascal
Pascal
1 pascal is a pressure of 1 Newton acting over an area of 1 square meter.
Mole
1 mole is defined as 12gm of Carbon-12 containing 6.02 × 10 to the power 23 atoms.
Number of mole = mass of substance / molar mass
Molar mass
Mass of 1 mole of the substance
Measured in gm/mol
Specific heat capacity
It is the energy required to raise the temperature of 1 kg of a substance by 1 K.
Heat capacity = mass × specific heat capacity
Latent heat
Energy released of absorbed when a substance undergoes a change of state without a change in it’s temperature.
Specific latent heat
Defined as the heat required to convert 1 kg of substance from 1 phase to another a constant temperature.
Humidity
Amount of water vapor present in a gas or in the atmosphere.
