The best equation of all time!

Readers of Physics World magazine voted the most popular equations of all time. But what are their meanings? The magazine's deputy editor, Dr. Matin Durrani, gave a simple guide to the top five equations.

1. First class - Clerk Maxwell's electromagnetic theory

∇.D = p

∇.B = 0

∇xE = -∂B / ∂t

∇xH = ∂D / ∂t + j

Clerk Maxwell (Photo: dbhs.wvusd)

Where D is the displacement field, E is the electric field, B is the magnetic-flux density, H is the magnetic field (magnetic-field strength), p is the Free charge density and j are free current density.

This formula was written in 1873 by the famous Scottish physicist James Clerk Maxwell. They describe the transformation of an electromagnetic wave - such as a beam of light, an X-ray or a microwave - in space and time. .

The interesting thing about this equation is that they show that electric fields and magnetic fields - two types of fields that scientists previously thought were not related to each other - are actually closely linked. After this discovery, physicists continue to associate the electromagnetic force with two other types of natural forces, the strong nuclear force and the weak nuclear force - two types of interaction at the nucleus of atoms.

The result of the hypothesis is called the Standard Uniform Model of Particle Physics. The biggest challenge for the scientific community is now to find out whether gravity - the fourth fundamental force in nature - is related to this model. So Maxwell is actually the first physicist to integrate natural forces into a single theoretical framework.

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Euler mathematician (Photo: astrocosmo)

Maxwell's program is widely used in the telecommunications industry, for example, to design antennas for your mobile phone.

2. First rank - Euler's equation

e ^{i Õ} + 1 = 0

The equation was discovered by Swiss mathematician Leonhard Euler in the 18th century. Physicists liked this equation because it contained nine basic concepts of mathematics in a single formula.

These 9 concepts include: pi by the circumference of a circle divided by its diameter, i - is the square root of -1, and e - is 2.71828. The other six concepts are: multiplication, addition, equation, one, zero and "exponential calculation".

What is this equation for you? Nothing. Euler's formula is purely a mathematical formula with no obvious relevance to reality, although it is considered "beautiful" by some physicists .
My personal prediction: It will probably be in school uniform!

3. Newton's second law

Newton (Photo: bun.kyoto-u.ac)

F = ma

This formula describes the fact that if you use a force (F) acting on an object with a mass m, this object will achieve a certain acceleration. The equation was described by Isaac Newton in the late 17th century.

Benefits of equations? Newton's second law can be used to explain how your new Mini Cooper can accelerate from 0 to 60 miles per hour. And simply, you have to remember it to solve class exercises. 10 motivational parts if you don't want to eat geese!

4. Pythagoras's theorem

a² + b² = c²

A favorite school recipe. Pythagoras's theorem explains the relationship between the edges of a right triangle. If a and b are the lengths of the two right-angled edges and c is the length of the hypotenuse. This formula was described by the ancient Greek scientist Pythagoras in the 6th century BC.

Application of this equation? Pythagoras's equation assists in triangulation measurements, helping to show the position of someone using a mobile phone just by using feedback signals from three other mobile antennas.

5. Schrödinger's equation

HΨ = EΨ

Austrian physicist Erwin Schrödinger (photo: physics) The formula was written by Austrian physicist Erwin Schrödinger in the mid-1920s. It describes the movement of subatomic particles (like electrons), and is the background the foundation of quantum physics.

With small particles like electrons, one cannot say their position in space as well as their movement speed. All you can do is assume they are in a certain position for a certain period of time. The symbol Ψ in the equation is called a "wave function" - describing the ability of an object to exist at different points in space.

Benefits of equations? Schrödinger's equation has many applications in electronic devices. For example, it is used by Quantum Beam Company in Cambridge to build a laser-based system that allows connecting your home computer to the Internet without wires. Someone said: People with solids use each of these equations to do everything: From nanotechnology, low-dimensional systems to new materials.

6. Einstein's equation

E = mc²

Einstein (Photo: krux)

Einstein's famous formula shows that mass and energy are inseparable. If an object has mass m, it will have a resting energy of E = mc², where c is the speed object of light. Because c is extremely large - about 300,000 km / s - so even microscopic objects also have very large rest energy.

Equally, energy also has mass. You may hear a lot about this equation in 2005, during the 100th anniversary of Einstein's discovery of it as part of his theory of relativity.

Benefits of this equation? E = mc² determines the amount of energy released when the atoms are divided in the reactor of a nuclear power plant. In nuclear reactions the mass no longer preserves. Part of the mass is lost, instead the energy-generating response is large enough to be used for nuclear power plants or is the cause of the disaster in Japan's two cities by two atomic bombs. thrown by America after World War II.