There is a point charge in vacuum, and the charge quantity is Q. according to Coulomb's law and the definition of electric field strength, the expression of electric field strength at the point where q is R is derived

There is a point charge in vacuum, and the charge quantity is Q. according to Coulomb's law and the definition of electric field strength, the expression of electric field strength at the point where q is R is derived

From Coulomb's Law: F = kqqr2 from the definition of electric field intensity: e = FQ solution: e = kqr2 answer: the expression of electric field intensity at the point where q is R is e = kqr2