Electric Charge: Definition, Types & Units

Study Notes

Electric charge is a property of matter that produces and experiences electrical and magnetic effects.

A point charge is a charge whose spatial size is negligible compared to other distances.
Charge is a scalar quantity, meaning it can be added or subtracted algebraically.
Charge is transferable and can be transferred from one body to another.
Charge is always associated with mass, but mass can exist without charge.
Charge is conserved, meaning it cannot be created or destroyed.
The numerical value of an elementary charge is independent of velocity.

Charge produces electric fields and magnetic fields.
A charged particle at rest produces only an electric field, while a moving charge produces both electric and magnetic fields.
An accelerated charge radiates energy in the form of electromagnetic waves.
Charge is quantized, meaning it can only take on discrete values.
The smallest unit of charge is the charge of an electron, which is -1.6 × 10^(-19) C.

Electric charge can be positive, negative, or zero, while mass is always positive.
The charge carried by a body does not depend on its velocity, while mass increases with velocity.
Charge is quantized, while the quantization of mass is yet to be established.
Electric charge is conserved, while mass is not conserved and can be converted into energy.
The force between charges can be attractive or repulsive, while the gravitational force between two masses is always attractive.

A body can be charged by friction, which involves the transfer of electrons from one body to another.
Friction can cause one body to become positively charged and the other negatively charged.
Charging by friction involves the conservation of charge, resulting in equal amounts of positive and negative charges.
Other methods of charging include electrostatic induction.