Why is the voltage of each element uneven in the loop, and why is the electric field strength uneven

Circuit theory is an approximation using Maxwell's equations under certain conditions.

Maxwell's equations can describe all electromagnetic phenomena in nature, and their essence is that the change of the electric field with space is proportional to the change of the magnetic field with time, and the change of the electric field with time is directly proportional to the change of the magnetic field with space.

Maxwell's equations include the following: Faraday's law of electromagnetic induction (the curl of the electric field e is equal to the negative number of the magnetic induction intensity b as a function of time); Ampere's loop theorem (i.e., the total current law, the curl of the magnetic field strength h is equal to the displacement current density j plus the rate of change of the displacement vector d to time); The principle of magnetic flux continuity (the divergence of b is 0, i.e., the magnetic induction line is a closed curve); Gauss's theorem (the divergence of d is equal to the bound charge density); Boundary conditions for the material.

Each material has the following parameters: dielectric constant epsilon [Greek letters cannot be typed], permeability U (pronounced miu), conductivity cigma. where d = epsilon*e, b = u*h, j = cigma*e, resistivity is the reciprocal of conductivity.

At the interface of the material, since E and B are both vectors, they can be decomposed into two parts, perpendicular to the interface and parallel to the interface. The parallel components of e and h are constant on both sides of the interface, and the perpendicular components of b and d are constant on both sides of the interface, from which the electric and magnetic field distributions of space can be obtained, and then the current density distribution can be obtained.

The most important law in circuit theory is called Kirchhoff's law, which has the following two points:

1) The inflow current of any node in the circuit at any time is equal to the outflow current;

2) The sum of voltages of all components in any closed loop of the circuit is 0 in the same reference direction.

Kirchhoff's law applies to centralized-parameter circuits, which are wavelengths whose size is much smaller than the voltage (for alternating current), and centralized-parameter circuits can be described by linear equations and ordinary differential equations. If the size of the circuit is comparable to the wavelength of the voltage, and the size of each component (including resistance, capacitance, inductance, etc., but excluding the wire) is still much smaller than the wavelength, then a distributed parameter circuit needs to be used, and the distributed parameter circuit needs to solve the temporal and spatial distribution of voltage and current, which is described by partial differential equations; If the dimensions of the components in the circuit are comparable to the wavelengths, they can only be solved using the theory of electromagnetic fields (i.e., Maxwell's equations).

Ohm's law was proposed earlier than Maxwell's equations, because at that time electricity and magnetism were studied separately, and it was not until Oersted discovered the magnetic effect of electric current and Faraday discovered electromagnetic induction that people realized that electricity and magnetism were inseparable; Maxwell summarized the results of his predecessors and proposed Maxwell's equations.

In fact, you just need to understand the scope of application of Ohm's law, the nature of resistance, electric current, and the concept of resistivity. This question is not difficult.

In the same circuit, the voltage of each component is proportional to the size of the electric group, and the voltage at both ends of the component is different depending on the resistance of the element. The electric field strength is proportional to the voltage, so the electric field strength is unevenly distributed.

The electric field strength is not uniform due to the different voltages and currents required for each element in the circuit.