Q: Which law states that ... ?  
A: 
The energy equivalence (E) of a given mass (m) is that mass times the square of the speed of light in a vacuum (c).
In other words: E = mc^{2}
(proposed by Albert Einstein in 1905) 

"The energy equation" 
When a body is wholly or partially immersed in fluid, it is acted upon by a buoyant force equal to the weight of the displaced fluid 

Archimedes' Principle 
A robot may not injure a human being or, through inaction, allow a human being to come to harm 

Isaac Asimov's First Law of Robotics 
Equal volumes of different gases, at the same temperature and pressure, contain the same number of molecules 

Avogadro's Law 
For a fluid in motion, an increase in speed occurs simultaneously with a decrease in pressure or potential energy 

Bernoulli's Principle 
For a given mass of gas at constant temperature, the pressure is inversely proportional to the volume 

Boyle's Law 
If your back is to the wind, low pressure is on your right (in the Northern Hemisphere) 

Buys Ballot's Law 
For a given mass of gas at constant volume, the pressure is directly proportional to the temperature 

Charles' Law or Gay Lussac's Law 
The pressure exerted by a mixture of gases in a fixed volume is equal to the sum of the pressures exerted by each gas if it occupied that volume alone 

Dalton's Law of Partial Pressures 
There are no positive integers x, y, and z such that x^{n} + y^{n} = z^{n}
in which n is a natural number greater than 2 


Fermat's Last Theorem 
The rate of effusion (flow through a hole) in a gas is inversely proportional to the square root of the mass of its particles 

Graham's Law 
For an elastic material, strain is proportional to applied stress (or, extension is proportional to the force applied) 

Hooke's Law 
The planets orbit the sun in elliptical orbits with the sun at one focus 

Kepler's First Law 
The line connecting a planet to the sun sweeps out equal areas in equal amounts of time 

Kepler's Second Law 
The time required for a planet to orbit the sun, called its period, is proportional to the
long axis of the ellipse raised to the power of 3/2. The constant of proportionality is the same for all the planets 

Kepler's Third Law 
A system in chemical equilibrium, if subjected to a disturbance, tends to change in a way that opposes the disturbance 

Le Chatelier's Principle 
The direction of current induced in a circuit by a change in magnetic field is such that the magnetic field produced by this current will oppose the original field 

Lenz's Law 
Cod law with no scientific basis, stating that in any given system, if anything can possibly go wrong, it will. For example, if you drop a piece of toast, it will always land buttered side down (except when you drop it deliberately to prove the law). Can be seen as an ironic, unscientific version of the second law of thermodynamics 

Murphy's Law (Sod's Law) 
A body remains in a state of rest or uniform motion unless acted upon by a force 

Newton's First Law of Motion 
Rate of acceleration is directly proportional to the force 

Newton's Second Law of Motion 
For every action there is an equal and opposite reaction 

Newton's Third Law of Motion 
Of two equivalent theories or explanations, all other things being equal, the simpler one is to be preferred 

Occam's Razor 
The current between two points (through a conductor) is directly proportional to the potential difference across them (I = V/R) 

Ohm's Law 
Work expands so as to fill the time available for its completion 

Parkinson's Law 
In a right angled triangle, the square on the hypotenuse is equal to the sum of the squares on the other two sides 

Pythagoras' Theorem 
If A, B and C are distinct thermodynamic bodies, and
both A and C are in thermodynamic equilibrium with B, then A is also in
thermodynamic equilibrium with C. 

Thermodynamics, Zeroth Law of 