Grade 12
  1. Advanced mechanics  1.1. Dynamics  1.1.1. Motion in two and three dimensions  1.1.2. Advanced Projectile Motion and Range Equations  1.1.3. Relative motion in different reference frames  1.1.4. Motion of charged particles in electric and magnetic fields  1.1.5. Non-uniformly accelerated motion in multiple dimensions  1.2. Dynamics  1.2.1. Newton's laws and applications in non-inertial frames  1.2.2. Dynamics of particle systems  1.2.3. Non-conservative forces and energy dissipation  1.2.4. Momentum in variable mass systems (rocket momentum)  1.2.5. Lagrangian and Hamiltonian Mechanics (Introduction)  1.3. Work, Energy and Power  1.3.1. Work done by non-conservative forces  1.3.2. Power in rotational and translational motion  1.3.3. Advanced Conservation Laws and Applications  1.3.4. Potential energy surface and stability  1.4. Advanced rotational speed  1.4.1. Torque in three dimensions  1.4.2. Moment of inertia for irregular bodies  1.4.3. Gyroscopic motion and precession  1.4.4. Rotational work–energy theorem  1.4.5. Euler's equations of rotational motion  1.5. Gravitational force  1.5.1. Advanced Orbital Mechanics  1.5.2. Lagrange points and stability of orbits  1.5.3. Gravitational time dilation  1.5.4. Escape velocity and energy considerations  1.5.5. Tidal force and the Roche limit
  2. Fluid mechanics and thermodynamics  2.1. Fluid dynamics  2.1.1. Applications of Bernoulli's Principle  2.1.2. Navier-Stokes equations and fluid resistance  2.1.3. Turbulent vs. Laminar Flow  2.1.4. Surface tension and capillary action  2.2. Advanced Thermal Physics  2.2.1. Thermodynamic equilibrium and heat engines  2.2.2. Entropy and the Second Law of Thermodynamics  2.2.3. Maxwell's demon and statistical thermodynamics  2.2.4. Thermodynamic potential and free energy
  3. Oscillations and waves  3.1. Advanced Simple Harmonic Motion  3.1.1. Coupled oscillations and common modes  3.1.2. Damped and driven oscillations  3.1.3. Phase space and resonance  3.1.4. Anharmonic oscillations  3.2. Wave motion  3.2.1. Advanced wave equations and dispersion  3.2.2. Shock Waves and Sonic Booms  3.2.3. Doppler effect in electromagnetic waves  3.2.4. Wave–particle duality
  4. Electromagnetism  4.1. Electrostatics  4.1.1. Gauss's law in unilateral charge distribution  4.1.2. Electric potential for complex charge configuration  4.1.3. Electrostatic energy and self-energy of a system  4.1.4. Dielectrics and Polarization  4.2. Current Electricity  4.2.1. Advanced Circuit Analysis (Thevenin and Norton theorems)  4.2.2. RC, RL and RLC circuits in AC and DC  4.2.3. Superconductivity and applications  4.3. Advanced Magnetism and Electromagnetic Induction  4.3.1. Magnetic fields in conductors and plasma  4.3.2. Lenz's law in time-dependent magnetic fields  4.3.3. Eddy Currents and Applications  4.3.4. Magnetic dipole moment and torque on electric current loops  4.4. Alternating Current and Electromagnetic Waves  4.4.1. LC Circuits and Resonance  4.4.2. Maxwell's equations and electromagnetic wave transmission  4.4.3. Applications of Electromagnetic Waves  4.4.4. Polarization and reflection of EM waves
  5. Optics  5.1. Geometrical Optics  5.1.1. Aberrations in optical systems  5.1.2. Advanced lens and mirror formulas  5.1.3. Optical Instruments and Adaptive Optics  5.2. Wave optics  5.2.1. Diffraction at single and multiple slits  5.2.2. Optical Coherence and Interferometry  5.2.3. Holography and applications
  6. Modern and quantum physics  6.1. Special relativity  6.1.1. Time expansion and length contraction  6.1.2. Relativistic energy and mass  6.1.3. Relativistic Doppler effect  6.2. Quantum mechanics  6.2.1. Schrödinger equation and wave function  6.2.2. Quantum tunneling and applications  6.2.3. Heisenberg uncertainty principle  6.2.4. Quantum superposition and entanglement  6.3. Nuclear physics  6.3.1. Binding energy and mass defect  6.3.2. Neutrino physics and beta decay  6.3.3. Nuclear Fission and Fusion  6.4. Particle physics  6.4.1. Standard Model and fundamental interactions  6.4.2. The Higgs boson and symmetry breaking  6.4.3. Antimatter and CP violation
  7. Astrophysics and cosmology  7.1. General relativity and gravity  7.1.1. Einstein's field equations  7.1.2. Gravitational waves and their detection  7.1.3. Black holes and event horizons  7.2. Cosmology  7.2.1. Dark matter and dark energy  7.2.2. Cosmic microwave background radiation  7.2.3. The expansion of the universe and Hubble's law

Grade 12 ↓


Electromagnetism


Electromagnetism is one of the fundamental forces of nature and is responsible for the interaction between charged particles. It combines the two effects of electricity and magnetism into a single phenomenon. Understanding electromagnetism involves figuring out how electric charges create electric fields and how electric currents produce magnetic fields.

Basic concepts of electric charge

Electric charge is a fundamental property of electrons, protons, and other subatomic particles. There are two types of charge: positive and negative. The interaction between these charges is governed by the following rules:

  • Like charges repel each other.
  • Unlike charges attract each other.

The unit of charge is coulomb (C), and the charge of an electron is about -1.6 × 10-19 C.

Electric field and electric force

The electric field is the region around a charged object where other charged objects experience a force. The strength of this field is measured in volts per meter (V/m). The electric field E due to a point charge Q can be calculated using Coulomb's law:

    E = K * (|Q| / R2)

Where:

  • k is the Coulomb constant, about 8.99 × 109 N m2/C2
  • r is the distance from the charge
Why

Electric field lines radiate outward from a positive charge and inward towards a negative charge.

Electric potential and voltage

Electric potential, measured in volts (V), is the energy required to move a unit charge from a reference point to a specific point within the field without any acceleration. Voltage is the difference in electric potential between two points. The relationship between electric field and potential difference is given as:

    V = E * D

Where:

  • V is the potential difference
  • E is the electric field strength
  • d is the distance between the points

Magnetism and magnetic fields

Magnetism arises from the movement of electric charges. The magnetic field is a vector field that describes the magnetic effect on moving electric charges, electric currents, and magnetic materials. The symbol B usually represents it, and the unit of measurement is Tesla (T).

A simple magnet or a current-carrying wire can demonstrate the presence of a magnetic field. You can visualize the magnetic field with imaginary lines. Here, the lines emerge from the north pole of the magnet and re-enter through the south pole, as shown below:

S N

Here, the red lines represent the magnetic field lines around a bar magnet.

Electromagnetic induction

Electromagnetic induction is the process by which a changing magnetic field within a coil of wire induces a voltage at the ends of the coil. It is the basic principle behind many electrical generators and transformers. Faraday's law of induction describes this process quantitatively:

    ε = -n * (dΦ/dt)

Where:

  • ε is the induced electromotive force (EMF)
  • N is the number of turns of the coil
  • dΦ/dt is the rate of change of magnetic flux

Alternating current and generators

Generators convert mechanical energy into electrical energy using the principle of electromagnetic induction. In an alternating current (AC) generator, the coil rotates in a magnetic field, causing the magnetic flux through the coil to change, producing an alternating voltage.

A simple AC voltage can be described by the equation:

    v(t) = v₀ * sin(ωt + φ)

Where:

  • V(t) is the voltage at time t
  • V₀ is the peak voltage
  • ω is the angular frequency
  • φ is the phase angle

Electromagnetic waves

Electromagnetic waves are waves of electric and magnetic fields that travel through space. These waves do not require a medium and can travel through a vacuum. Light, radio waves, X-rays, and microwaves are examples of electromagnetic waves. They travel at the speed of light (c ≈ 3 × 108 m/s) and can be described by the wave equation:

    c = λ * f

Where:

  • λ is the wavelength
  • f is the frequency

The electromagnetic spectrum classifies electromagnetic waves based on their wavelengths or frequencies. It ranges from long-wavelength radio waves to short-wavelength gamma rays.

The figure below shows the relationship between electric and magnetic fields in an electromagnetic wave:

l

The blue line represents the electric field, and the red line represents the magnetic field, both fields oscillating perpendicular to each other and to the direction of wave propagation.

Applications of electromagnetism

Electromagnetism has wide applications in modern technology:

  • Electric motors: use magnetic fields produced by electric currents to convert electrical energy into mechanical motion.
  • Transformers: use electromagnetic induction to transfer electrical energy between circuits, usually changing voltage levels.
  • Communications: Radio waves, a type of electromagnetic wave, are used in broadcasting, cell phones, and wireless networks.
  • Medical imaging: Technologies such as MRI rely on electromagnetic fields to create images of the inside of the human body.

Conclusion

Electromagnetism is the basis of physics, providing insight into how charged particles interact and forming the basis of many of the technologies that define modern life. By understanding the principles of electric and magnetic fields, electromagnetic waves, and the applications of these principles, one can appreciate the depth and breadth of electromagnetism's impact.


Grade 12 → 4


U
username
0%
completed in Grade 12

← Prev (3.2.4)
Wave–particle duality
Next (4.1) →
Electrostatics

Comments 



Electromagnetism

https://www.physicsflow.com/g12/4?pfal=en