F: Lorentz force or amperometric force, q: electric charge, v: velocity, E: electric field strength, Φ (= ΔBS or B ΔS, B is the magnetic induction, S is the surface area): magnetic flux, S: the surface area, the formula can be seen through the influence of the magnetic force strength The formula shows that it is not only the magnetic flux that affects the magnetic strength, but also the surface. So it is not the magnetic flux is large, the magnetic force is large.
2, the definition of magnetic induction: charge in the electric field by the electric field force is a certain direction and the direction of the electric field at the point of the same or opposite. Current in the magnetic field somewhere in the magnetic field force (ampere force), and the current in the magnetic field placed in the direction of the current is related to the current when the direction of the current and the direction of the magnetic field parallel to the current by the smallest ampere force, equal to zero; when the direction of the current and the direction of the magnetic field is perpendicular to the current by the largest ampere force. A point charge q moving with velocity v in a magnetic field is acted upon by a force f . Under the given conditions of the magnetic field, the magnitude of f is related to the direction of motion of the charge . When v is along or reversed from a particular direction, the force is zero; when v is perpendicular to this particular direction the force is maximum, Fm. Fm is proportional to |q| and v, and the ratio is independent of the moving charge, reflecting the nature of the magnetic field itself, and is defined as the magnitude of the magnetic induction, i.e., the direction of B is defined as the right-handed helical advance from the direction of the maximum force, Fm, exerted on the positive charge to the direction of the charge's movement, v. The right-handed helical advance is defined by the right-handed helical advance from the direction of the maximum force, Fm, applied to the positive charge. . After the definition of B, the force on the moving charge in the magnetic field B can be expressed as F = QVB, which is the Lorentz force formula.