Inside a conductor at electrostatic equilibrium, electric field is
Correct answer: Zero
Why: Free charges redistribute until the internal field vanishes.
AP Physics C: E&M Practice Questions
Answer original AP-style diagnostic questions, review explanations, and identify the next unit to study.
AP Physics C: Electricity and Magnetism diagnostic practice set
These are original practice questions, not copied College Board items. Use official released questions for final calibration.
Question 1 of 3
Review the reasoning after you finish
The interactive set keeps answers hidden while you work. This review section remains crawlable and gives every student a complete correction path after the attempt.
For an isolated charged capacitor, inserting a dielectric makes voltage
Correct answer: Decrease
Why: Charge stays fixed while capacitance increases, so V=Q/C decreases.
Lenz's law determines induced-current
Correct answer: Direction
Why: The induced effect opposes the change in magnetic flux.
Practise each section under its own calculator rule
Practising with a calculator you will not be handed is the most common way a practice score stops predicting an exam score. Set each practice block up to match the section it rehearses.
| Section or part | What you may use | What that means for your work |
|---|---|---|
| Multiple choice | Four-function, scientific, or graphing calculator | Allowed throughout. Symmetry arguments beat calculation on most items. |
| Free response | Four-function, scientific, or graphing calculator | The work is calculus: line integrals, surface integrals, and separable differential equations. |
| Provided for the whole exam | Equations and constants table | Both sections. Maxwell's equations are on it; choosing the right surface or loop is on you. |
How practice should cover the complete course
Electrostatics
Coulomb's law, fields, Gauss's law
Required: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Conductors, Capacitors, and Dielectrics
Potential, energy, capacitance
Required: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Electric Circuits
Steady-state and transient RC behavior
Required: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Magnetic Fields
Forces, Biot-Savart, Ampère's law
Required: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Electromagnetism
Induction, Faraday and Lenz laws
Required: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Use the result to focus your AP Physics C: Electricity and Magnetism review
Read the score as a map, not a verdict
Each answer shows a relationship between course knowledge and an exam decision. A miss may mean that a definition is unclear, a representation was misread, or the right method was not selected. Compare each miss with these AP Physics C: Electricity and Magnetism priorities before choosing the next unit or practice set.
- Gauss-law symmetry
- Potential versus field
- RC transients
- Magnetic force directions
- Flux and Lenz-law signs
Next steps after the AP Physics C: Electricity and Magnetism diagnostic
Use a four-step correction cycle
- Write the rule or idea behind every miss.
- Solve a second problem of the same type without looking back.
- Mix that skill with two older units tomorrow.
- Complete official released questions under authentic timing.
Questions about AP Physics C: Electricity and Magnetism exam practice
How many questions are on the AP Physics C: Electricity and Magnetism exam?
The published format is 42 questions on multiple choice and 4 questions on free response. Multiple choice — About 2 minutes each. If a question needs a full integral, it usually has a symmetry shortcut instead. Free response — About 24 minutes each. Later parts build on earlier symbolic results, so keep your notation consistent.
Which AP Physics C: Electricity and Magnetism units should I practise first?
This course publishes no percentage weightings, so practise by course priority: Gauss-law symmetry; Potential versus field; RC transients. Then mix those with the units you have not touched in a fortnight.
Can I use a graphing calculator while I practise for AP Physics C: Electricity and Magnetism?
Only where the exam allows one, and practising otherwise builds the wrong habit. Multiple choice: Allowed throughout. Symmetry arguments beat calculation on most items. Free response: The work is calculus: line integrals, surface integrals, and separable differential equations. Provided for the whole exam: Both sections. Maxwell's equations are on it; choosing the right surface or loop is on you.
What is the most common way students lose points on AP Physics C: Electricity and Magnetism?
Choosing a Gaussian surface with no symmetry. Gauss's law is always true but only useful when the field is uniform over the surface you picked.
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