← Physics C: Electricity and Magnetism syllabus

United StatesPhysics C: Electricity and Magnetism

Unit 8: Electric Charges, Fields, and Gauss's Law

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How is charge conserved during charging, and what distinguishes conduction, induction and polarization?

Topic 8.2 Conservation of Charge and the Process of Charging: apply conservation of charge to charging by friction, conduction and induction, and explain grounding and polarization.
A calculus-based answer to AP Physics C E&M Topic 8.2, covering conservation and quantisation of charge, charging by friction, conduction and induction, grounding, and the polarization of conductors and insulators.
10 min answer →

How does Coulomb's law quantify the force between charges, and how do you combine these forces as vectors?

Topic 8.1 Electric Charge and Coulomb's Law: model the electrostatic force between point charges with Coulomb's law and add the forces from several charges as vectors.
A calculus-based answer to AP Physics C E&M Topic 8.1, covering electric charge, Coulomb's law for point charges, the inverse-square form, and combining Coulomb forces by superposition, with worked vector problems.
11 min answer →

How do you integrate over a continuous charge distribution to find the electric field it produces?

Topic 8.4 Electric Fields of Charge Distributions: set up and evaluate integrals to find the electric field of continuous charge distributions such as rods, rings and arcs.
A calculus-based answer to AP Physics C E&M Topic 8.4, covering linear, surface and volume charge densities, setting up dE integrals, exploiting symmetry, and deriving the field of rods, rings and arcs.
12 min answer →

What is the electric field, how does a point charge produce one, and how do field lines represent it?

Topic 8.3 Electric Fields: define the electric field as force per unit charge, calculate the field of point charges, and represent fields with field lines.
A calculus-based answer to AP Physics C E&M Topic 8.3, covering the electric field as force per charge, the field of a point charge, superposition of fields, field lines, and the field inside and around conductors.
11 min answer →

What is electric flux, and how is it computed as a surface integral of the field?

Topic 8.5 Electric Flux: define electric flux as the surface integral of the field and compute it for uniform and non-uniform fields through flat and closed surfaces.
A calculus-based answer to AP Physics C E&M Topic 8.5, covering the area vector, the dot product, the flux surface integral, uniform-field and angle-dependent flux, and the net flux through a closed surface.
10 min answer →

How does Gauss's law use symmetry to find the electric field of a charge distribution?

Topic 8.6 Gauss's Law: apply Gauss's law with a chosen Gaussian surface to find the field of spherically, cylindrically and planar-symmetric charge distributions.
A calculus-based answer to AP Physics C E&M Topic 8.6, covering Gauss's law, choosing a Gaussian surface, and deriving the field of spheres, lines and planes, plus the field inside conductors.
12 min answer →