Electromagnetism in Class 12 Physics

Electromagnetic Force: The interaction between electrically charged particles; one of the four fundamental forces of nature.
Magnetic Field (B): A vector field around magnetic materials and electric currents. Measured in teslas (T).
Electric Field (E): A vector field around charged particles. Measured in volts per meter (V/m).

Coulomb's Law: Describes the force between two point charges.
- F = k * (|q1 * q2| / r²), where k is Coulomb's constant.
Ampere's Law: Relates magnetic fields to the electric current that produces them.
- ∮B·dl = μ₀ * I_enclosed
Faraday's Law of Electromagnetic Induction: A changing magnetic field induces an electromotive force (emf).
- ε = -dΦ/dt, where Φ is the magnetic flux.
Lenz's Law: The direction of induced current is such that it opposes the change in magnetic flux.

Diamagnetic Materials: Slightly repel magnetic fields; example: copper.
Paramagnetic Materials: Weakly attract magnetic fields; example: aluminum.
Ferromagnetic Materials: Strongly attracted; can retain magnetization; example: iron.

Properties: Transverse waves consisting of oscillating electric (E) and magnetic (B) fields perpendicular to each other.
Speed of Light (c): c = 3 x 10^8 m/s, in a vacuum, where c = 1/√(ε₀μ₀).

Electromagnets: Created by electric currents; used in motors, generators, and transformers.
Induction Cooktops: Use electromagnetic induction to heat pots directly.
Magnetic Resonance Imaging (MRI): Employs strong magnetic fields and radio waves for medical imaging.

Lorentz Force: F = q(E + v × B), where q is charge, v is velocity, and B is the magnetic field.
Magnetic Flux (Φ): Φ = B·A·cos(θ), where A is the area and θ is the angle between B and A.

Electromagnetism involves the study of electric and magnetic fields and their interactions.
Fundamental laws govern the behavior of charges, fields, and magnetic materials.
Understanding these concepts is crucial for various practical applications and technologies.

Electromagnetic Force: One of the four fundamental forces, governing interactions between charged particles.
Magnetic Field (B): A vector field surrounding magnetic materials and electric currents, measured in teslas (T).
Electric Field (E): A vector field around charged particles, quantified in volts per meter (V/m).

Coulomb's Law: Formula governing the force (F) between two point charges, expressed as F = k * (|q1 * q2| / r²).
Ampere's Law: Connects magnetic fields to the electric current creating them, denoted by ∮B·dl = μ₀ * I_enclosed.
Faraday's Law of Electromagnetic Induction: Describes how a changing magnetic field produces electromotive force (emf), represented as ε = -dΦ/dt, where Φ stands for magnetic flux.
Lenz's Law: The induced current flows in a direction that opposes the change in magnetic flux, reinforcing system stability.

Diamagnetic Materials: Very weakly repel magnetic fields; example includes copper.
Paramagnetic Materials: Exhibit weak attraction to magnetic fields; aluminum is a typical example.
Ferromagnetic Materials: Strongly attracted to magnetic fields and can maintain magnetization over time; iron is a key example.

Wave Characteristics: Transverse waves with oscillating electric (E) and magnetic (B) fields that are perpendicular to each other.
Speed of Light (c): Travels at c = 3 x 10^8 m/s in a vacuum, calculated using c = 1/√(ε₀μ₀), where ε₀ is the electric permittivity and μ₀ is the magnetic permeability.

Electromagnets: Formed by electric currents, utilized in motors, generators, and transformers for converting electrical energy into mechanical energy.
Induction Cooktops: Utilize electromagnetic induction to directly heat cookware, resulting in efficient cooking.
Magnetic Resonance Imaging (MRI): Combines strong magnetic fields and radio waves for detailed imaging in medical diagnostics.

Lorentz Force: Expressed as F = q(E + v × B), where q represents charge, v is velocity, and B indicates the magnetic field.
Magnetic Flux (Φ): Defined as Φ = B·A·cos(θ), where A is the surface area and θ is the angle between the magnetic field and the area vector.

Electromagnetism encompasses the study of electric and magnetic fields and their mutual interactions.
Fundamental laws govern the behaviors exhibited by charges and magnetic materials, forming the backbone of electromagnetic theory.
Grasping these principles is essential for understanding a variety of practical technologies and applications.