Key Physical Constants and Units

Fundamental Constants

These constants are essential for calculations in electricity, magnetism, and modern physics.

• Planck's constant (h): or

• Electron mass (m_e):

• Atomic mass unit (u):

• Earth's radius (R_E):

• Earth's mass (M_E):

Electrostatics

Coulomb's Law

Describes the force between two point charges:

• Where

Electric Field and Potential

• Electric field:

• Field due to point charge:

• Surface charge:

• Potential energy:

• Work:

• Potential difference:

• Potential due to point charge:

• Potential energy of two charges:

Gauss's Law

Capacitance and Dielectrics

Capacitance

• For capacitors in series:

• For capacitors in parallel:

• Energy stored:

Electric Current and Circuits

Current and Resistance

• Ohm's Law:

• Resistance:

• Resistivity temperature dependence:

• Power:

• Current density:

• Relation to electric field:

Circuits

• Series resistors:

• Parallel resistors:

• RC time constant:

• Charging capacitor:

• Discharging capacitor:

Magnetism

Magnetic Force and Fields

• Force on moving charge:

• Force on current:

• Torque on loop:

• Magnetic dipole:

• Potential energy:

Biot-Savart and Ampère's Law

• Biot-Savart Law:

• Ampère's Law:

• Field inside solenoid:

Electromagnetic Induction

Faraday's Law and Inductance

• Faraday's Law:

• Induced emf (moving conductor):

• Mutual inductance:

• Self-inductance:

• Energy in inductor:

AC Circuits

• Impedance:

• Inductive reactance:

• Capacitive reactance:

• Resonant frequency:

Maxwell's Equations and Electromagnetic Waves

• Speed of light:

• Wave relation:

• Energy density: ,

• Poynting vector:

Geometric Optics

Reflection and Refraction

• Snell's Law:

• Lens equation:

• Magnification:

Optical Instruments

• Power of lens: (in diopters)

• Combination of lenses:

Wave Optics

Interference and Diffraction

• Double-slit:

• Single-slit:

• Diffraction grating:

• Rayleigh criterion:

Special Relativity

• Time dilation:

• Length contraction:

• Lorentz factor:

• Relativistic momentum:

• Relativistic energy:

• Energy-momentum relation:

Quantum Physics

Photoelectric Effect and Photons

• Photon energy:

• Photoelectric equation:

• Photon momentum:

Atomic Models and Spectra

• Bohr radius:

• Bohr energy levels:

• Rydberg formula:

Uncertainty Principle

• Position-momentum:

• Energy-time:

• Reduced Planck's constant:

Table: Selected Physical Constants

Additional info:

• Some equations and constants were inferred and expanded for clarity and completeness.

• Where only symbols or fragments were present, standard forms of the equations were provided.

• Table values were reconstructed from context and standard physics references.