Coulomb's Law and Charging

The force between charges at rest.

The force between two small charges acts along the line joining them. It grows with the product of the charges and falls with the square of the distance. It attracts unlike charges and pushes like charges apart.

Objects become charged by friction, by contact or by induction, but charge is never created or destroyed, only moved around. Between two electrons the electric push is vastly stronger than their gravitational pull.

• Doubling the distance cuts the force to a quarter.
• Charge is conserved and comes in multiples of e.
• Induction charges an object without touching it.

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