Lecture

Electromagnetic Waves: Properties and Interactions

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Description

This lecture covers the fundamental aspects of electromagnetic waves, including their propagation, characteristics, and interactions with matter. It begins with the equation of propagation for monochromatic electromagnetic waves and discusses the electromagnetic spectrum, highlighting the visible domain and its significance. The instructor explains the energy of photons in relation to frequency and introduces key concepts such as irradiance, emittance, and solid angle. The lecture further explores the interactions of electromagnetic radiation with surfaces and the atmosphere, categorizing them into elastic and inelastic interactions. The principles of absorption, diffusion, and attenuation are examined, along with their implications for environmental detection. The instructor emphasizes the importance of understanding these interactions for applications in remote sensing and environmental monitoring. The lecture concludes with a discussion on the spectral properties of electromagnetic waves and their relevance in various scientific fields.

This video is available exclusively on Mediaspace for a restricted audience. Please log in to MediaSpace to access it if you have the necessary permissions.

Watch on Mediaspace

Official source

Related concepts (32)

Electromagnetic spectrum

The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 1025 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus.

Electromagnetic radiation

In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. Types of EMR include radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays, all of which are part of the electromagnetic spectrum. Classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric and magnetic fields.

Irradiance

In radiometry, irradiance is the radiant flux received by a surface per unit area. The SI unit of irradiance is the watt per square metre (W⋅m−2). The CGS unit erg per square centimetre per second (erg⋅cm−2⋅s−1) is often used in astronomy. Irradiance is often called intensity, but this term is avoided in radiometry where such usage leads to confusion with radiant intensity. In astrophysics, irradiance is called radiant flux.

Radiant exitance

In radiometry, radiant exitance or radiant emittance is the radiant flux emitted by a surface per unit area, whereas spectral exitance or spectral emittance is the radiant exitance of a surface per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. This is the emitted component of radiosity.

Light

Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light.

Related lectures (64)

Photon Picture of Electromagnetic Waves

Explores the photon concept in electromagnetic waves, including energy, momentum, emission by charges, coherence length, and the electromagnetic spectrum.

Photon: Quantum Properties and Experiments

Explores the quantum properties of photons, covering their wave-particle duality and implications in various experiments.

Radiometry/Photometry

Explores radiometry and photometry concepts, including the history of photomedicine and the measurement of electromagnetic radiation and light.

Electromagnetic Waves: Wave Equation and Description

Explores the wave equation for electromagnetic waves, Maxwell's derivation, the electromagnetic spectrum, and plane wave description.

Chemical Equilibria and Reactivity