---
title: "Spectrophotometer — AP Chem Definition & Beer-Lambert Law"
description: "A spectrophotometer measures how much light a solution absorbs at a chosen wavelength. In AP Chem Topic 3.13, it's the tool behind Beer-Lambert Law (A = εbc) and finding concentration."
canonical: "https://fiveable.me/ap-chem/key-terms/spectrophotometer"
type: "key-term"
subject: "AP Chemistry"
---

# Spectrophotometer — AP Chem Definition & Beer-Lambert Law

## Definition

A spectrophotometer is an instrument used in scientific analysis that measures how much a chemical substance absorbs (or transmits) at each wavelength of light.

## Related Study Guides

- [3.13 Beer-Lambert Law ](/ap-chem/unit-3/beer-lambert-law/study-guide/smCHzraorVz6qlWW1oeB)

## Review

### Related Terms

- Photodetector: A device that converts incoming photons into an electrical signal for measurement purposes.
- [Cuvette](/ap-chem/key-terms/cuvette): A small tube-like container with straight sides and round or square cross section for holding samples in spectroscopic experiments.
- Sample Solution: The mixture containing the compound whose absorption spectrum is being measured.