Name: electromagnetic wave reflection at conductors
Uploaded: 2023-09-18T17:11:17.000Z
Duration: 1 min 15 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Physical Science

PS.7

PS.7.a

Standing Electromagnetic Waves

Sıkı bir ipte oluşan duran dalgaları hatırlayın. 
Duran dalgalar, zıt yönde hareket eden ancak aynı genlik ve frekansa sahip iki dalganın birleşimidir.
Y-z düzlemine yerleştirilmiş mükemmel bir iletken levha düşünün. Doğrusal polarize bir elektromanyetik dalga, negatif x yönünde hareket ederken tabakaya çarpar.
Gelen dalga, iletkenin yüzeyindeki akımı indükler, bu da ek elektrik alanlarına neden olur ve gelen dalga ile aynı frekans ve genliğe sahip yansıyan bir dalga üretir.
Bu iki dalganın üst üste binmesi, duran dalgayı oluşturur. Bu ifadeleri basitleştirmek, elektrik alanın ve manyetik alanın büyüklüklerinin sıfır olduğu dalga üzerindeki noktaları sağlar. Bunlara düğümler veya düğüm düzlemleri denir.
Bir antinod, genliğin maksimum pozitiften maksimum negatif yer değiştirmeye gittiği bir noktadır.
Elektrik alanın düğümleri, manyetik alanların antinodları ile çakışır ve bunun tersi de geçerlidir. Bu nedenle, her noktada 90 derece faz dışıdırlar.

<ol>
	<li>Genç, H.D. ve Freedman, R.A. (2012). Modern Fizik ile Üniversite Fiziği. San Francisco, Kaliforniya: Pearson. Bölüm 32.5; sayfa 1069–1070.</li>
</ol>

duran elektromanyetik dalgalar

Elektromanyetik dalgalar yansıtılabilir; bir iletkenin veya bir dielektrik malzemenin yüzeyi bir yansıtıcı gibi davranabilir. Elektrik ve manyetik alanlar süperpozisyon prensibine uyar, dolayısıyla elektromanyetik dalgalar da uyar. Bir olay dalgası ile yansıyan elektromanyetik dalganın süperpozisyonu gerilmiş bir tel üzerinde oluşturulan duran dalgaya benzer bir duran dalga oluşturur.

Diyelim ki mükemmel bir iletken levha yz-düzlemine yerleştirildi ve negatif x-yönünde hareket eden doğrusal kutupsal bir elektromanyetik dalga ona çarptı. Elektrik alanı mükemmel bir iletkenin yüzeyiyle paralel bir bileşene sahip olamaz, bu yüzden elektrik alanı yz-düzlemi boyunca her yerde sıfır olmalıdır. Olay elektromanyetik dalganın elektrik alanı her zaman yz-düzlemi boyunca sıfır değildir, ancak bu olay dalgası iletkenin yüzeyinde titreşen akımlara neden olur ve buna bağlı olarak ek bir elektrik alanı ortaya çıkarır. Bu alanın ve olay alanının vektör toplamı olan net elektrik alanı, içerde ve iletkenin yüzeyinde her yerde sıfırdır. İletkenin yüzeyinde indüklenen akımlar aynı zamanda uçaktan uzaklaşan yansıyan bir dalga da üretir. Süperpozisyon prensibi, herhangi bir noktadaki toplam alanın olay ve yansıyan dalgaların elektrik alanlarının vektör toplamı olduğunu belirtir, manyetik alan gibi. Olay ve yansıyan dalgaların süperpozisyonu duran dalgaları oluşturur.

<img alt="Equation1" src="/files/ftp_upload/13829/13829_Equation_1.png" style="text-align: center; height: 20px;" />

<img alt="Equation2" src="/files/ftp_upload/13829/13829_Equation_2.png" style="text-align: center; height: 18px;" />

Bu ifadeleri basitleştirme, elektrik alanı ve manyetik alan niceliklerinin sıfır olduğu dalga noktalarını sağlar. Bunlar düğüm veya düğüm düzlemleri olarak adlandırılır. Ardışık iki düğüm düzleminin ortasında en büyük genlik düzlemleri bulunur; bunlar antinode düzlemleridir.

Toplam elektrik alanı bir sinüs fonksiyonudur ve toplam manyetik alan bir kosinüs fonksiyonudur. Bu nedenle, iki alanın sinusoidal değişimleri her noktada faz farkıdır. Elektrik alan düğümleri manyetik alanların antinodlarıyla çakışır ve bunun tersi de geçerlidir. Bu nedenle, her noktada 90° faz farkına sahiptirler. Bu, bir yönde seyahat eden bir dalga için elektrik ve manyetik alanların sinusoidal değişimlerinin herhangi bir noktada aynı fazda olduğunun aksine.

Duran Elektromanyetik Dalgalar

Elektromanyetik dalgalar yansıtılabilir; Bir iletkenin veya bir dielektriğin yüzeyi bir reflektör görevi görebilir. Elektrik ve manyetik alanlar uyarken...

Education

JoVE Core

Physics

Fizik

Unit 1

Ünite 1

Electromagnetic Waves

Elektromanyetik Dalgalar

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

electromagnetic wave reflection at conductors

Electromagnetic waves can reflect from a conductor or a dielectric. When the reflected wave combines with the incoming wave, the result is a standing electromagnetic wave. This is similar to the standing waves formed on a stretched string.

To see how this happens, consider a perfect conductor placed in the yz-plane. A linearly polarized electromagnetic wave moving in the negative x-direction strikes the surface. The electric field cannot have a component parallel to the surface of a perfect conductor, so the electric field must be zero everywhere in the yz-plane.

The incident wave is not zero at the surface, but it induces oscillating currents on the conductor. These currents create an additional electric field. The net electric field is the vector sum of the incident and induced fields, and it is zero everywhere inside and on the conductor's surface. The same surface currents also produce a reflected wave that moves away from the plane.

The total field at any point is the vector sum of the incident and reflected electric fields, and the same idea applies to the magnetic field. This superposition creates standing waves. The places where the electric or magnetic field magnitude is zero are called nodes, or nodal planes. The planes halfway between adjacent nodes have maximum amplitude and are called antinodal planes.

For these standing waves, the total electric field follows a sine function, while the total magnetic field follows a cosine function. The two fields are therefore 90° out of phase at each point. Electric field nodes line up with magnetic field antinodes, and magnetic field nodes line up with electric field antinodes. This is different from a wave traveling in one direction, where the electric and magnetic fields are in phase at a given point.

Electromagnetic Wave Reflection at Conductors

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key terms and concepts

Explore how reflected electromagnetic waves form standing patterns at conductors, with nodes, antinodes, and electric and magnetic fields out of phase.

Electromagnetic Wave Reflection at Conductors | JoVE K12

physics

JoVE Temel Fizik, kinematik, dinamik, akışkanlar mekaniği, statik, dalgalar ve akustik dahil olmak üzere temel fizik konularının teorisini ve uygulamasını kısa ve anlaşılması kolay animasyonlu videolarla tanıtıyor. Ek olarak, sektör içindeki bilim insanı videoları, dünya çapındaki günümüz laboratuvarlarında gerçekleştirilen klasik ve orijinal araştırma deneylerinde ilgili kavramların uygulanmasını göstermektedir.

Minnesota Academic Standards in Science

9-12

4.2.1 9P.3.2.2.1

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New Jersey Student Learning Standards for Science

High School

waves-and-their-applications-in-technologies-for-information-transfer

Waves and Their Applications in Technologies for Information Transfer

HS-PS4-5

Alabama Course of Study Science

9-12.PS.2.2.e

9-12.P.3.7.c

Florida Department of Education

SC.912.P.10

SC.912.P.10.17

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

P-PS4-2

P-PS4-4

Earth and Space Science (ESS)

Earth’s Place in the Universe

E-ESS1-2.

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PS.7.b

Electromagnetic Wave Reflection at Conductors

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