Charge and Current Fundamentals In electricity and electromagnetism, electric charge is a fundamental property of matter that gives rise to electrostatic forces...
In electricity and electromagnetism, electric charge is a fundamental property of matter that gives rise to electrostatic forces. Charge comes in two types - positive and negative - and like charges repel while opposite charges attract.
The total charge in an isolated system always remains constant; charge can neither be created nor destroyed, only transferred between objects. This is known as the principle of conservation of charge.
An electric current is the rate of flow of electric charge. Conventional current is defined as the flow of positive charge, while electron flow refers to the movement of negatively charged electrons.
Current (I) is related to charge (Q) and time (t) by the equation:
I = Q/t
Materials can be classified as conductors or insulators based on their ability to allow charge flow:
In metals, electrical conduction occurs due to the movement of free electrons. These delocalized electrons are able to flow through the metal lattice when an electric potential is applied, constituting an electric current.
Problem: Calculate the current when a charge of 60 C flows through a circuit in 2 minutes.
Solution:
Understanding charge, current, and their relationships lays the foundation for advanced topics in electricity and electromagnetism in A Level Physics.