Question: Electromagnetic force plays a major role in what?
About the article "Electromagnetism", section "Abstract".

Candidate passages:
Electromagnetism, or the electromagnetic force is one of the four fundamental interactions in nature, the other three being the strong interaction, the weak interaction, and gravitation.
This force is described by electromagnetic fields, and has innumerable physical instances including the interaction of electrically charged particles and the interaction of uncharged magnetic force fields with electrical conductors.
The word "electromagnetism" is a compound form of two Greek terms, ἢλεκτρον, "ēlektron", "amber", and μαγνήτης, "magnetic", from "magnítis líthos" (μαγνήτης λίθος), which means "magnesian stone", a type of iron ore.
The science of electromagnetic phenomena is defined in terms of the electromagnetic force, sometimes called the Lorentz force, which includes both electricity and magnetism as elements of one phenomenon.
During the quark epoch, the electroweak force split into the electromagnetic and weak force.
The electromagnetic force plays a major role in determining the internal properties of most objects encountered in daily life.
Ordinary matter takes its form as a result of intermolecular forces between individual molecules in matter.
Electrons are bound by electromagnetic wave mechanics into orbitals around atomic nuclei to form atoms, which are the building blocks of molecules.
This governs the processes involved in chemistry, which arise from interactions between the electrons of neighboring atoms, which are in turn determined by the interaction between electromagnetic force and the momentum of the electrons.
There are numerous mathematical descriptions of the electromagnetic field.
In classical electrodynamics, electric fields are described as electric potential and electric current in Ohm's law, magnetic fields are associated with electromagnetic induction and magnetism, and Maxwell's equations describe how electric and magnetic fields are generated and altered by each other and by charges and currents.
The theoretical implications of electromagnetism, in particular the establishment of the speed of light based on properties of the "medium" of propagation (permeability and permittivity), led to the development of special relativity by Albert Einstein in 1905.
As outlined below, the electromagnetic force is written in terms of E and B, using vector calculus and Maxwell's equations symmetry in the terms containing E and B are sought for, and introducing the Maxwell stress-tensor simplifies the result.in the above relation for conservation of momentum, formula_1 is the momentum flux density and plays a role similar to formula_2 in Poynting's theorem. 
The historical figure Akbar Khan plays a major role in George MacDonald Fraser's novel "Flashman. 
Publication history.
Belladonna plays a major role in the first "Rogue" mini-series. 
The nonhomogeneous electromagnetic wave equation in terms of the field tensor is modified from the special relativity form to formula_40 where "Racbd" is the covariant form of the Riemann tensor and formula_41 is a generalization of the d'Alembertian operator for covariant derivatives.
Using formula_42 Maxwell's source equations can be written in terms of the 4-potential 2, p. 569 as, formula_43 or, assuming the generalization of the Lorenz gauge in curved spacetime formula_44 formula_45 where formula_46 is the Ricci curvature tensor.
This the same form of the wave equation as in flat spacetime, except that the derivatives are replaced by covariant derivatives and there is an additional term proportional to the curvature.
The wave equation in this form also bears some resemblance to the Lorentz force in curved spacetime where "Aa" plays the role of the 4-position.