---
title: "Planck's Constant — AP Chem Definition & Exam Guide"
description: "Planck's constant (h = 6.626 × 10⁻³⁴ J·s) links a photon's energy to its frequency via E = hν, the core equation of Topic 3.12 and the photoelectric effect."
canonical: "https://fiveable.me/ap-chem/key-terms/plancks-constant"
type: "key-term"
subject: "AP Chemistry"
---

# Planck's Constant — AP Chem Definition & Exam Guide

## Definition

Planck's constant is a physical constant that is the quantum of electromagnetic action which relates the energy carried by a photon to its frequency. Its symbol is h and it has a value of 6.62607015 × 10^-34 m^2 kg / s.

## Related Study Guides

- [3.12 Properties of Photons](/ap-chem/unit-3/photoelectric-effect/study-guide/aSateoQF56rKcT1xgLeY)

## Review

### Related Terms

- Photon Energy: The amount of energy carried by a single photon, calculated using Planck’s constant and the frequency or wavelength of light.
- [Frequency](/ap-chem/key-terms/frequency): The number of complete cycles per unit time for any periodic motion (like waves). Imagine this as how often you jump on a trampoline - more jumps per minute means higher frequency!
- [Wavelength](/ap-chem/key-terms/wavelength): The distance over which the wave's shape repeats. It’s like measuring the length from one crest to another in ocean waves.