---
title: "Test Charge — AP Physics 2 Definition & Exam Guide"
description: "A test charge is a tiny positive charge used to probe an electric field without disturbing it. It's how E = F/q is defined in AP Physics 2 Topic 5.1."
canonical: "https://fiveable.me/ap-physics-2-revised/key-terms/test-charge"
type: "key-term"
subject: "AP Physics 2"
---

# Test Charge — AP Physics 2 Definition & Exam Guide

## Definition

A test charge refers to a small positive or negative charge used to measure electric fields or determine properties of charged objects. It is typically assumed to have negligible influence on the electric field itself.

## Related Study Guides

- [5.1 Electric Fields & Forces](/ap-physics-2-revised/unit-5/electric-fields-forces/study-guide/DBJDysHHkjOAbV9uEqvO)

## Review

### Related Terms

- Electric Field: A region around a charged particle or group of particles where other charged particles experience a force.
- [Coulomb's Law](/ap-physics-2-revised/key-terms/coulombs-law): Describes the electrostatic interaction between two charged objects based on their charges and distance between them.
- Electric Potential Energy: The energy associated with an electrically charged particle due to its position relative to other charged particles in an electric field.