Name: transverse fields in electromagnetic waves
Uploaded: 2023-04-30T12:46:03.000Z
Duration: 1 min 30 s
Channel: JoVE

K12 Standards

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North Carolina K-12 Science Standard Course of Study

9-12

Physics

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Waves and Their Applications in Technologies for Information Transfer

PS.Phy.7.1

Plane Electromagnetic Waves I

yz düzlemine paralel bir düzlemle iki farklı bölgeye bölünmüş bir xyz koordinatı düşünün.
Sol tarafta +y ve +z yönlerinde düzgün bir elektrik ve manyetik alan bulunurken, sağ taraf alansızdır.
Dalga cephesi adı verilen bu sınır düzlemi, sabit bir hızla +x yönünde hareket eder.
Herhangi bir anda, alanların yayılma yönüne dik herhangi bir düzlem üzerinde tekdüze olduğu bu tür dalgalara düzlem dalgaları denir.
Bu dalgalar Maxwell denklemlerini sağlar. Dikdörtgen bir Gauss kutusu düşünün.
Elektrik alanı y yönü boyunca olduğundan, x yönü ve z yönü boyunca yüzey için elektrik akıları sıfırdır.
Üst yüzey için, akı alt yüzeye zıttır ve sıfır net akı verir.
Kutu elektrik yükü içermediğinden, elektrik ve manyetik akı sıfırdır.
Bu nedenle, Gauss yasası elektromanyetik radyasyon için geçerlidir.
Bu nedenle, elektrik ve manyetik alan vektörleri birbirine ve yayılma yönüne diktir ve enine doğa gösterir.

<ol>
	<li>Genç, H.D. ve Freedman, R.A. (2012). Modern Fizik ile Üniversite Fiziği. San Francisco, Kaliforniya: Pearson. Bölüm 32.2; sayfa 1055–1056.</li>
	<li>Stax'ı açın. (2019). Üniversite Fiziği Cilt 2. [Web sürümü]. <a href="https://openstax.org/details/books/university-physics-volume-2">https://openstax.org/details/books/university-physics-volume-2 adresinden alındı</a>; Bölüm 16.2; Sayfa 706–707.</li>
</ol>

uçak elektromanyetik dalgalar i

Maxwell denklemlerinin en önemli tahmini, elektrik ve manyetik alanların birleşmiş bir şekilde elektromanyetik (EM) dalgalar halinde uzayda yayılmasıdır. Maxwell denklemleri boş uzayda geçerli olduğu için tahmin edilen elektromanyetik dalgaların yayılması için bir ortama ihtiyaç duyulmaz. Bir EM dalgası, yüke uygulanan yük başına kuvvet olarak tanımlanan bir elektrik alan ve hareketli yüke uygulanan yük başına kuvvet olan bir manyetik alan içerir.

EM alanının sadece x-koordinatı ve zamanın bir fonksiyonu olduğu varsayılır. Bu nedenle, elektrik alanın y-bileşeni E_y(x, t) olarak yazılır ve manyetik alanın z-bileşeni B_z(x, t) olarak yazılır. Serbest alanın varsayımı nedeniyle serbest yükler veya akımlar olmadığı için Maxwell denklemindeki sarmalanan yük ve akım sıfır olarak kabul edilir.

Elektrik alanı için Gauss yasası uygulanabilirliği, kenar uzunluğu Δx olan kare kesitli bir dikdörtgen Gauss yüzeyi varsayarak incelenir. Elektrik alanın y-bileşeni, kutunun üst ve alt yüzünde aynıdır. Bu nedenle, her iki yüzeydeki akılar birbirini iptal eder. Benzer şekilde, elektrik alanın z-bileşimi tarafından yüzeyin iki yan tarafından geçen net akı da iptal edilir. Dolayısıyla, yüzeyden herhangi bir net akı, yalnızca elektrik alanın x-bileşiminden gelir. Elektrik alanın y- veya z-bağımlılığı olmadığı için, E_x(x, t), yüzeyin bir yüzünde sabit olan A alanına sahip bir kutunun yüzünde sabit bir değeri E_x(x + Δx, t) olan elemanlarının üzerinde sabittir. Gauss yasasıuygulanarak x-bileşiminin net akısı bulunur.

<img alt="Equation1" src="/files/ftp_upload/13822/13822_Equation_PT_1.svg" style="text-align: center; height: 30px;" />

Çünkü enc ile sarmalanan yük, sıfır olduğu için bileşimin net akısı da sıfırdır ve yukarıdaki denklem herhangi bir Δx için Ex(x, t) = Ex(x + Δx, t) olarak ifade eder. Bu tür bir bileşen Ex(x, t) x-ekseninde yayılan bir elektromanyetik dalga parçası olmayacaktır, bu yüzden bu dalga için Ex(x, t) = 0'dır. Dolayısıyla, elektrik alanın yönüne dik olan elektrik alanın yalnızca Ey(x, t) ve Ez(x, t) bileşenleri sıfır olmayan bileşenleridir.

Elektrik alanı için Gauss yasasıyerine manyetizma için Gauss yasasıkullanılarak benzer bir argüman geçerlidir. Bu, manyetik alanın da dalga yayılma yönüne dik olduğunu gösterir. Elektromanyetik dalgası, bu nedenle, salınan elektrik ve manyetik alanlarının yayılma yönüne dik olarak bir transvers dalga olduğunu gösterir.

Uçak Elektromanyetik Dalgalar I

Uzayda elektromanyetik (EM) dalgalar olarak yayılan birleşik elektrik ve manyetik alanların varlığı, elektromanyetik (EM) dalgalar olarak en önemli tahmindir ...

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Unit 1

Ünite 1

Electromagnetic Waves

Elektromanyetik Dalgalar

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

transverse fields in electromagnetic waves

Electromagnetic waves are made of electric and magnetic fields that move through space together. Maxwell's equations predict these waves, and they can travel in free space without a medium. The electric field acts on a stationary charge, while the magnetic field acts on a moving charge.

For a wave traveling along the x-axis, the fields are written as Ey(x, t) and Bz(x, t). In free space, there are no free charges or currents, so the charge enclosed and current terms in Maxwell's equations are set to zero. This lets us test which field components can remain in the wave.

To apply Gauss's law for electric fields, a rectangular Gaussian surface with a square cross-section of side l and a third side of length Δx is used. The y-component of the electric field is the same on the top and bottom sides, so those fluxes cancel. The z-component through the two lateral sides also cancels, so any net flux comes only from Ex.

Because Ex depends only on x and time, it is constant over one face of the box and may have a different value on the opposite face. Gauss's law gives zero net flux because the enclosed charge is zero. That means Ex(x, t) = Ex(x + Δx, t) for any Δx, so Ex(x, t) is not part of the wave and must be zero. The electric field components left in the wave are Ey(x, t) and Ez(x, t), both perpendicular to the direction of travel.

A similar argument applies to the magnetic field by using Gauss's law for magnetism instead of Gauss's law for electric fields. This shows that the magnetic field is also perpendicular to the direction of propagation. An electromagnetic wave is therefore a transverse wave, with oscillating electric and magnetic fields at right angles to the wave's motion.

Transverse Fields in Electromagnetic Waves

transverse-fields-in-electromagnetic-waves

electromagnetic waves

Maxwell’s Equations Behind EM Waves

Maxwell’s equations explain how electric and magnetic fields work together to create electromagnetic waves. James Clerk Maxwell brought together the ideas of Oersted, Coulomb, Gauss, and Faraday and built a single theory of electromagnetism. Together with the Lorentz force law, his equations describe the laws of electricity and magnetism. A key part of Maxwell’s work is the symmetry in the equations. Faraday’s law shows that a changing magnetic field produces an electric field. Maxwell added...

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Heinrich Hertz used sparks and tuned circuits to show that electromagnetic waves could be produced in the lab. Starting in 1887, the German physicist ran experiments that confirmed electromagnetic waves exist and travel at the speed of light. Hertz built an alternating-current RLC circuit. RLC stands for resistor, inductor, and capacitor. The circuit was set to a known resonant frequency and connected to a loop of wire. High voltage across the gap in the loop created sparks. Those sparks gave...

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Electromagnetic Waves in Everyday Technology

Electromagnetic waves are grouped by wavelength and frequency. This set of waves is called the electromagnetic spectrum. It includes radio waves, microwaves, infrared, visible light, X-rays, and gamma rays. Radio waves have wavelengths from millimeters to kilometers. They are often used for audio communication, such as radios. In many cases, they come from alternating current in the wires of a broadcast antenna. Radio waves also carry AM and FM radio, cellular phone signals, and TV signals. <br...

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plane electromagnetic waves i

Electromagnetic waves are made of electric and magnetic fields that move through space together. Maxwell's equations predict these waves, and they can travel in free space without a medium. The electric field acts on a stationary charge, while the magnetic field acts on a moving charge. For a wave traveling along the x-axis, the fields are written as Ey(x, t) and Bz(x, t). In free space, there are no free charges or currents, so the charge enclosed and current terms in Maxwell's equations are...

plane electromagnetic waves ii

Faraday’s Law in a Plane Wave

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propagation speed of electromagnetic waves

propagation-speed-of-electromagnetic-waves

Maxwell’s Equations and Light Speed

Electromagnetic waves follow Ampere’s law when there is no conduction current. A plane wavefront moves in the positive x-direction. To analyze it, a rectangle is placed in the xz-plane with its area vector pointing in the positive y-direction. The line integral around the rectangle is taken counterclockwise. The magnetic field is zero on some sides and perpendicular on others. It is parallel to one side, and that side gives a non-zero contribution to the integral. Because the left side of...

electromagnetic waves in matter

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energy carried by electromagnetic waves

How EM Waves Transfer Energy

Electromagnetic waves transfer energy through their electric and magnetic fields. This energy can be easy to notice, like the warmth from the summer sun, or harder to feel, like the energy in gamma rays that can damage living cells. The fields in an electromagnetic wave can exert forces on charges in a system. They can move those charges and do work on them. Even if a wave is not absorbed right away, it still carries energy away from its source. If some of the wave energy is absorbed, the...

intensity of electromagnetic waves

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momentum and radiation pressure

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key terms and concepts

See why electromagnetic waves are transverse. Learn how Maxwell’s equations show that electric and magnetic fields stay perpendicular to the direction of travel.

Transverse Fields in Electromagnetic Waves | JoVE K12

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Transverse Fields in Electromagnetic Waves

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