JoVE Logo

Sign In

Electromagnetic (EM) radiation consists of electric and magnetic field components oscillating in planes perpendicular to each other and mutually perpendicular to radiation propagation through space. EM radiation can be classified as a wave, characterized by the properties of waves such as wavelength (denoted as λ) and frequency (represented by ν).

Wavelength is the distance between two consecutive peaks (the highest point) or troughs (the lowest point) in the wave. Frequency is the number of repeating waves or wave cycles that pass a given point in a fixed time. Different types of electromagnetic radiation have varying wavelengths and frequencies. The electromagnetic spectrum is the ordered collection of electromagnetic radiation grouped by frequency or wavelength. The wavelength and frequency are related to the speed of the radiation through a medium. The speed of radiation in a vacuum (denoted as c) is a universal physical constant with a value of approximately 3 × 108 m/s.

Figure1

Therefore, wavelength and frequency are inversely related. Radiation with a high frequency features a low wavelength, and vice versa.

Figure2

In addition to behaving like a wave, electromagnetic radiation can also be considered a collection of particles called photons. A photon is the smallest unit or "quantum" of light or electromagnetic radiation. It has no mass or charge but carries energy. Each photon possesses a definite quantity of energy, which can be transferred to matter upon interaction. The energy of a photon (denoted as E) is directly proportional to the frequency and inversely proportional to the wavelength. The equation relating a photon's energy to its radiation frequency is known as Planck’s equation.

Figure3

Planck’s constant is denoted by h with a value of 6.626 × 10−34 m2 kg s−1.

From Chapter 12:

article

Now Playing

12.1 : Dual Nature of Electromagnetic (EM) Radiation

Introduction to Molecular Spectroscopy

1.6K Views

article

12.2 : Interaction of EM Radiation with Matter: Spectroscopy

Introduction to Molecular Spectroscopy

894 Views

article

12.3 : Molecular Spectroscopy: Absorption and Emission

Introduction to Molecular Spectroscopy

628 Views

article

12.4 : Spectrophotometry: Introduction

Introduction to Molecular Spectroscopy

2.3K Views

article

12.5 : Ultraviolet and Visible (UV–Vis) Spectroscopy: Overview

Introduction to Molecular Spectroscopy

2.0K Views

article

12.6 : UV–Vis Spectroscopy: Molecular Electronic Transitions

Introduction to Molecular Spectroscopy

920 Views

article

12.7 : UV–Vis Spectrometers

Introduction to Molecular Spectroscopy

819 Views

article

12.8 : UV–Vis Spectrum

Introduction to Molecular Spectroscopy

756 Views

article

12.9 : UV–Vis Spectroscopy: Beer–Lambert Law

Introduction to Molecular Spectroscopy

1.1K Views

article

12.10 : Photoluminescence: Fluorescence and Phosphorescence

Introduction to Molecular Spectroscopy

133 Views

article

12.11 : Variables Affecting Phosphorescence and Fluorescence

Introduction to Molecular Spectroscopy

55 Views

article

12.12 : Deactivation Processes: Jablonski Diagram

Introduction to Molecular Spectroscopy

117 Views

article

12.13 : Photoluminescence: Applications

Introduction to Molecular Spectroscopy

72 Views

article

12.14 : Fluorescence and Phosphorescence: Instrumentation

Introduction to Molecular Spectroscopy

123 Views

JoVE Logo

Privacy

Terms of Use

Policies

Research

Education

ABOUT JoVE

Copyright © 2025 MyJoVE Corporation. All rights reserved