Electricity

In physics, electrical phenomena can be described by the fundamental concept of electric charge: it is a property of matter that can be quantified. There are two types of charge: we call one kind of charge positive and the other negative. Through experiment, we find that like-charged objects repel and opposite-charged objects attract.

Hence, we find that there is a force between these charges that is directly proportional to the magnitude of the charge of the objects and inversely proportional to distance between them. If one object has a certain charge we will call q₁, and another has charge q₂, then we can express the force from q₁ on q₂ by:

F=(1/(4πε₀))*(q₁*q₂)/(r²)

Where r is the distance between the charges, and ε₀ is a universal constant. See Physical constants.

The unit of charge is called a Coulomb?.

Note that this formula, called [Coulomb's Law]? is only fully accurate when the charges are static or moving slowly. When charges start moving quickly, the [Electric field]? undergoes a transformation described by Einstein's Theory of Relativity, and [Magnetic field]?s are produced that effect the amount of force on q₁ and q₂.

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In electrical engineering, a positive current is a current flowing from a positive voltage to a negative voltage.

Natural forms of electricity: lightning?.

Humans use electricity. Electricity travels on conductors and is stopped by insulators. Some electrical devices that use the properties of electricty are called [electronic devices]?

Many animals are sensitivie to electric fields, some (eg sharks) more than others (eg people). A few generate their own electric fields, such as the [electric eel]?.