---
title: "AP Physics C: Electricity and Magnetism Guided Practice"
description: "Fiveable has 8,839 AP Physics C: Electricity and Magnetism multiple-choice practice questions across 6 units, plus 153 stimulus-based question sets built around a source. Practice one unit or topic at a time."
canonical: "https://fiveable.me/ap-physics-c-e-m/guided-practice"
type: "guided-practice"
subject: "AP Physics C: Electricity and Magnetism"
---

# AP Physics C: Electricity and Magnetism Guided Practice

## Overview

Fiveable has 8,839 AP Physics C: Electricity and Magnetism multiple-choice practice questions across 6 units, plus 153 stimulus-based question sets built around a source. Practice one unit or topic at a time.

## Practice Questions by Unit

- Unit 8 – Electric Charges & Fields: Gauss's Law: 1,784 multiple-choice questions, 30 stimulus sets
- Unit 9 – Electric Potential: 601 multiple-choice questions, 14 stimulus sets
- Unit 10 – Conductors and Capacitors: 958 multiple-choice questions, 26 stimulus sets
- Unit 11 – Electric Circuits: 2,451 multiple-choice questions, 40 stimulus sets
- Unit 12 – Magnetic Fields & Electromagnetism: 1,533 multiple-choice questions, 16 stimulus sets
- Unit 13 – Electromagnetic Induction: 1,512 multiple-choice questions, 27 stimulus sets

## Sample Question

A battery with internal resistance r is connected to a load resistor R. When R = r, the fraction of the total power generated by the battery that is delivered to the load is 0.50. If the load resistance is increased to R = 3r, what is the new fraction of power delivered to the load?

- (A) The fraction increases from 0.50 to 0.75
- (B) The fraction increases from 0.50 to 1.00
- (C) The fraction decreases from 0.50 to 0.25
- (D) The fraction decreases from 0.50 to 0.33

**Answer: (A)** Deriving the efficiency function n = P_load / P_total = (I^2 R) / (I^2 (R+r)) = R/(R+r) allows for prediction of the new value. Substituting R = 3r yields n = 3r/(3r+r) = 3/4 = 0.75. This demonstrates that efficiency increases as load resistance increases relative to internal resistance.

## Related Practice

- [Mathematical Routines FRQ practice: Mathematical Routines question questions scored by part](/ap-physics-c-e-m/frqs/mathematical-routines)
- [Representations FRQ practice: Translation Between Representations question questions scored by part](/ap-physics-c-e-m/frqs/translation-between-representations)
- [Experimental Design FRQ practice: Experimental Design and Analysis question questions scored by part](/ap-physics-c-e-m/frqs/experimental-design)
- [Qualitative/Quantitative FRQ practice: Qualitative/Quantitative Translation question questions scored by part](/ap-physics-c-e-m/frqs/qualitative-quantitative-translation)
- [AP Physics C: Electricity and Magnetism unit tests: a timed practice test for every unit](/ap-physics-c-e-m/unit-test)
- [AP Physics C: Electricity and Magnetism full-length practice exams](/ap-physics-c-e-m/practice-exams)
- [AP Physics C: Electricity and Magnetism subject hub](/ap-physics-c-e-m)

## About This Document

Canonical Fiveable pages are available as Markdown at the same path plus `.md`.

- [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns
- [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing
- [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`)
- [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`)