# Electric Field of Point Charge

 The electric field of a point charge can be obtained from Coulomb's Law:

The electric field from any number of point charges can be obtained from a vector sum of the individual fields. A positive number is taken to be an outward field; the field of a negative charge is toward it.

This electric field expression can also be obtained by applying Gauss' law.

Index

Electric field concepts
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# Electric Field of Point Charge

 The electric field of a point charge can be obtained from Coulomb's law: The electric field from any number of point charges can be obtained from a vector sum of the individual fields. A positive number is taken to be an outward field; the field of a negative charge is toward it.

This electric field expression can also be obtained by applying Gauss' law.
Index

Electromagnetic force
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# Electric and Magnetic Constants

In the equations describing electric and magnetic fields and their propagation, three constants are normally used. One is the speed of light c, and the other two are the electric permittivity of free space and the magnetic permeability of free space, . The magnetic permeability of free space is taken to have the exact value