### Avogadro's Law (Gases)

It states that equal volumes of gases at the same temperature and pressure contain the same number of molecules regardless of their chemical nature and physical properties. This number (Avogadro's number) is 6.022 X 1023. It is the number of molecules of any gas present in a volume of 22.41 litres and is the same for the lightest gas (hydrogen) as for a heavy gas such as carbon dioxide or bromine.

Stated in 1811 by the Italian chemist Amedeo Avogadro (1776-1856)

### Boyle's Law (Gases)

For a fixed amount of an ideal gas kept at a fixed temperature, P [pressure] and V [volume] are inversely proportional (while one doubles, the other halves). In other words product of the pressure and volume is exactly a constant for an ideal gas.

Propounded by Robert Boyle, an Irish Chemist in 1662

### Charles' Law (Gases)

It states that the volume of a gas is directly proportional to the temperature of the gas, provided the amount of gas and pressure are held constant.

It was first published by French natural philosopher Joseph Louis Gay-Lussac in 1802, giving credit to an unpublished work from the 1780s by Jacques Charles. It is also known as Gay-Lussac Law.

### Coulomb's Law (Electrostatics)

The magnitude of the Electrostatics force of interaction between two point charges is directly proportional to the scalar multiplication of the magnitudes of charges and inversely proportional to the square of the distances between them.

Published in 1783 by French physicist Charles Augustin de Coulomb

### Faraday's Law of Electromagnetic Induction

The induced electromotive force (EMF) in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit.

Published by English Physicist Michael Faraday in 1831.

### Hooke's Law of Elasticity

It states that, for relatively small deformations of an object, the displacement or size of the deformation is directly proportional to the deforming force or load.

Discovered by the English scientist Robert Hooke in 1660.

### Joule's Law (Electricity)

It states that, heat produced by an electric current is directly proportional to the resistance of the conductor, the square of the current, and the time for which it flows.

Given by the English physicist James Prescott Joule around 1850.