---
title: "Amperian Loop — AP Physics C: E&M Definition & Exam Guide"
description: "An Amperian loop is an imaginary closed path used with Ampère's law to find magnetic fields from symmetric currents, like wires, solenoids, and toroids."
canonical: "https://fiveable.me/ap-physics-c-e-m/key-terms/amperian-loop"
type: "key-term"
subject: "AP Physics C: E&M"
---

# Amperian Loop — AP Physics C: E&M Definition & Exam Guide

## Definition

An Amperian loop is an imaginary closed loop used to analyze the magnetic field around a current-carrying conductor or through a specific region in space. It helps determine the direction and magnitude of the magnetic field using Ampere's law.

## Related Study Guides

- [4.4 Biot–Savart Law and Ampère’s Law](/ap-physics-c-e-m/unit-4/biot-savart-law-amperes-law/study-guide/HChNR7z7O4ql5SF8879S)

## Review

### Related Terms

- [Ampere's Law](/ap-physics-c-e-m/key-terms/amperes-law): A mathematical equation that relates the magnetic field around a closed loop to the electric current passing through it.
- [Magnetic Flux](/ap-physics-c-e-m/key-terms/magnetic-flux): The measure of how much magnetic field passes through a given area. Amperian loops are used to calculate magnetic flux.
- Gauss's Law for Magnetism: Similar to Ampere's law, but applied to situations where there are no currents present. It relates the total magnetic flux passing through a closed surface to the magnetic field within that surface.