Electromagnetism

Fundamental Concepts


Electric charge: Electric charge is a fundamental property of matter. Objects can be positively charged, negatively charged, or neutral (having no net charge). Electric charge is measured in units of coulombs (C).
Electric field: An electric field is a force field that surrounds an electric charge. It exerts a force on other charges in the field. Electric fields are described by their strength and direction and can be visualized using electric field lines.
Electric potential: Electric potential is a scalar quantity that describes the amount of potential energy per unit charge at a given point in an electric field. It is measured in volts (V).
Magnetic field: A magnetic field is a force field that surrounds a magnet or a moving charged particle. It exerts a force on other magnets or moving charges in the field. Magnetic fields are described by their strength and direction and can be visualized using magnetic field lines.
Electromagnetic waves: Electromagnetic waves are waves of oscillating electric and magnetic fields that travel through space. They include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. Electromagnetic waves are characterized by their frequency, wavelength, and amplitude.
Maxwell's equations: Maxwell's equations are a set of four equations that describe the behavior of electric and magnetic fields. They relate the electric and magnetic fields to the sources of those fields, such as charges and currents.Electric current: An electric current is the flow of electric charge through a conductor, such as a wire. Electric current is measured in units of amperes (A).
Ohm's law: Ohm's law states that the current flowing through a conductor is directly proportional to the voltage applied across it, and inversely proportional to its resistance. It can be expressed mathematically as I = V/R, where I is the current, V is the voltage, and R is the resistance.
Electromagnetic induction: Electromagnetic induction is the production of an electromotive force (EMF) in a conductor when it is exposed to a changing magnetic field. It is the basis for the operation of electric generators and motors.
Lorentz force: The Lorentz force is the force exerted on a charged particle moving in a magnetic field. It is given by the equation F = q(E + v x B), where F is the force, q is the charge of the particle, E is the electric field, v is the velocity of the particle, and B is the magnetic field.
Coulomb's law: Coulomb's law describes the force between two electrically charged particles. It states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.Dielectric materials: Dielectric materials are insulators that can store electric charge in the form of an electric field. They are used in capacitors, which are electronic components that store and release electric energy.
Magnetic materials: Magnetic materials are materials that can be magnetized, such as iron, nickel, and cobalt. They are used in a variety of applications, including electric motors, generators, and magnetic storage devices.
Electromagnetic radiation: Electromagnetic radiation is the energy that is carried by electromagnetic waves. It includes all forms of electromagnetic waves, including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.
Ampere's law: Ampere's law relates the magnetic field to the current flowing through a wire. It states that the magnetic field around a wire is proportional to the current flowing through the wire and the distance from the wire.
Faraday's law: Faraday's law describes how a changing magnetic field induces an electromotive force (EMF) in a conductor. It states that the EMF induced is proportional to the rate of change of the magnetic field.

Electromagnetism Equations

Electric charge: Q = ne, where Q is the total charge, n is the number of charged particles, and e is the elementary charge (1.602 × 10^-19 C).
Electric field: E = F/q, where E is the electric field strength, F is the force exerted by the field, and q is the charge experiencing the field.
Electric potential: V = W/q, where V is the electric potential, W is the work done by an external force in moving a charge from one point to another, and q is the charge.
Magnetic field: B = F/qv, where B is the magnetic field strength, F is the force on a charged particle, q is the charge of the particle, and v is its velocity.
Electromagnetic waves: c = fλ, where c is the speed of light (3 × 10^8 m/s), f is the frequency of the wave, and λ is its wavelength.
Maxwell's equations: These are a set of four equations that describe the behavior of electric and magnetic fields. They are quite complex, but in their simplest form, they are:
Gauss's law for electric fields: ∇ · E = ρ/ε0Gauss's law for magnetic fields: ∇ · B = 0Faraday's law of electromagnetic induction: ∇ × E = -dB/dtAmpere's law with Maxwell's correction: ∇ × B = μ0(j + ε0(dE/dt))Electric current: I = ΔQ/Δt, where I is the current, ΔQ is the change in charge, and Δt is the time interval over which the charge flows.
Ohm's law: V = IR, where V is the voltage, I is the current, and R is the resistance of the conductor.
Electromagnetic induction: ε = -dΦ/dt, where ε is the induced EMF, Φ is the magnetic flux, and t is time.
Lorentz force: F = q(E + v x B), where F is the force on a charged particle, q is the charge of the particle, E is the electric field, v is the velocity of the particle, and B is the magnetic field.
Coulomb's law: F = k(q1q2)/r^2, where F is the force between two charged particles, k is Coulomb's constant (9 × 10^9 N m^2/C^2), q1 and q2 are the charges, and r is the distance between them.
Ampere's law: ∫ B · dl = μ0I, where B is the magnetic field, dl is a differential length element of a closed loop, I is the current passing through the loop, and μ0 is the permeability of free space.
Faraday's law: ε = -dΦ/dt, where ε is the induced EMF, Φ is the magnetic flux, and t is time.