Foundations

Current measures charge crossing a chosen surface per unit time.

An electric field assigns force per unit test charge.

Magnetic force depends on charge motion relative to the field.

A linear current-voltage relation requires suitable conditions.

Keep the heat and work sign convention explicit in an energy balance.

Apply entropy increase to the whole isolated system.

A simple gas model relates pressure, amount, volume and temperature.

One photon's energy is proportional to its frequency.

Lorentz transformations preserve a combined space-time separation.

Interaction forces act on different bodies in equal and opposite pairs.

Torque changes angular momentum about a specified origin.

Static fluid pressure rises with depth under gravity.

The hydrostatic upward force equals displaced-fluid weight.

Four field equations connect electric and magnetic fields with charge and current.

A quantum wavefunction evolves according to its Hamiltonian.

A normalized wavefunction assigns probabilities to position intervals.

The elementary charge has an exact SI numerical value.

The Boltzmann constant has an exact SI numerical value.

The mole is linked to a specified number of entities.

A specified frequency fixes the photometric SI reference.

The proton count of an atomic nucleus identifies its chemical element.

Isotopes share a proton count but have different neutron counts.

Atomic-number order reveals recurring patterns in electron structure and chemical properties.

Bonding describes interactions that bind atoms into molecules or extended structures.

The mole counts specified entities using the exact Avogadro constant.

Balanced coefficients relate the amounts consumed and produced by a reaction.

A chemical equation must preserve each element's atom count and the total charge.

At equilibrium, opposing reactions continue without net composition change.

In the Brønsted description, an acid donates a proton and a base accepts it.

Gibbs-energy change distinguishes thermodynamic favourability from reaction speed.