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Chapter 33

電磁波

Chapter 33

Electromagnetic Waves

James Clerk Maxwell formulated a single theory combining all the electric and magnetic effects scientists knew during that time, calling the phenomena his …
The German physicist Heinrich Hertz (1857–1894) was the first to generate and detect certain types of electromagnetic waves in the laboratory. …
Electromagnetic waves are categorized according to their wavelengths and frequencies, giving the electromagnetic spectrum. These waves are classified as …
The existence of combined electric and magnetic fields that propagate through space as electromagnetic (EM) waves is the most significant prediction of …
Consider a plane wavefront traveling in position x-direction with a constant speed. This wavefront can be utilized to obtain the relationship between …
Electromagnetic waves are consistent with Ampere's law. Assuming there is no conduction current Ampere's law is given as: Consider a plane …
Electromagnetic waves can travel in the vacuum as well as in matter. For example light, which is an electromagnetic wave, can travel through air, water, …
Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes, this energy is obvious, such as in the summer sun's …
The energy transport per unit area per unit time, or the Poynting vector, gives the energy flux of an electromagnetic wave at any specific time. For a …
An object absorbing an electromagnetic wave would experience a force in the direction of propagation of the wave. This force occurs because …
Electromagnetic waves can be reflected; the surface of a conductor or a dielectric can act as a reflector. As electric and magnetic fields obey the …
Maxwell's equations for electromagnetic fields are related to source charges, either static or moving. These fields act on a test charge, whose …
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the …
The radiation pressure applied by an electromagnetic wave on a perfectly absorbing surface equals the energy density of the wave. The wave's momentum …
The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological …
Lightning is one of the most common and destructive forces in nature and has long been studied using spectroscopic techniques, first with traditional …
Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by …
Channel sounders are used to measure channel characteristics for radio systems. There are several types of channel sounders used today: continuous-wave …