Force between charges is kq1q2/r².
Coulomb's law F=kq₁q₂/r² with k=8.99×10⁹ N·m²/C². The electric field E=F/q; potential V=kq/r. Field lines start on positive charge. Gauss's law ∮E·dA=Q/ε₀ simplifies symmetrical cases.
Two 1 µC charges 10 cm apart repel with 0.9 N.
Coulomb's law gives the force between charges and underlies the electric field used in capacitors, sensors and electrostatic devices.
Force between charges is kq1q2/r².
Coulomb's law gives the force between charges and underlies the electric field used in capacitors, sensors and electrostatic devices.
The field spreads over a sphere whose area grows with the square of the radius, so the field strength falls off in the same way.
It describes how strongly a material responds to an electric field, and it appears in the force constant and in capacitance.
Typical applications include estimating the force between two charged spheres in a test rig, designing an electrostatic precipitator with a strong field and modelling the field around a charged conductor in a sensor.
Study "Series and parallel capacitors and inductors" first (topic 18 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
Inverse-square law. Superposition of fields. Field inside a conductor is zero.
Two 1 µC charges 10 cm apart repel with 0.9 N.
The next topic is "Magnetic fields", which builds directly on this one.
It is classed as Beginner in Electrical Engineering (topic 19 of 106). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.