Dzidziso Yekutanga yeMafungu eElectromagnetic
Mafungu emagetsi akakosha pazvinhu zvakawanda zvesainzi netekinoroji yemazuva ano. Mafungu aya haangokoshi chete pakunzwisisa zvakasikwa asiwo ane mashandisirwo anoshanda muzvikamu zvakasiyana-siyana, zvakaita sekutaurirana, mushonga, uye mainjiniya. Pakati pawo, mafungu emagetsi anomiririra hukama huripo pakati pemagetsi nemagetsi, zvichipararira muchadenga. Kunzwisisa dzidziso huru dzemafungu emagetsi kunoita kuti munhu anzwisise misimboti iri pasi pesimba inodzora maitiro avo nekushandiswa kwavo.
Historical Background
Kudzidza nezvemafungu emagetsi kwakatanga nekushanda kwaJames Clerk Maxwell muzana remakore rechi19. Maequation aMaxwell, akaumbwa muma1860, ndiwo musimboti wedzidziso yemagetsi. Maequation aya anotsanangura kuti minda yemagetsi nemagineti inopararira sei uye inobatanidzwa sei. Basa raMaxwell rakabatanidza dzidziso dzakaparadzana dzemagetsi nemagineti uye rakafanotaura kuvapo kwemafungu emagetsi. Heinrich Hertz akazosimbisa kufungidzira kwaMaxwell kuburikidza nekuyedza muma1880, achipa humbowo hwechokwadi hwekuvapo kwemafungu.
Maequations aMaxwell
Maequations aMaxwell ane maequations mana akasiyana anotsanangura kuti minda yemagetsi (E) neminda yemagineti (B) inogadzirwa uye inochinjwa sei pakati payo uye nechaji nema currents:
1. Mutemo waGauss weMagetsi: Mutemo uyu unoti kuyerera kwemagetsi kuburikidza nepanzvimbo yakavharwa kunoenderana nechaji yakavharirwa nepanzvimbo iyoyo. Pamasvomhu, inotsanangurwa se:
\[
\nabla \cdot \mathbf{E} = \frac{\rho}{\epsilon_0}
\]
apo \(\rho\) iri huwandu hwechaji, uye \(\epsilon_0\) iri mvumo yenzvimbo yakasununguka.
2. Mutemo waGauss weMagineti: Mutemo uyu unoti kufamba kwemagineti kuburikidza nepanzvimbo yakavharwa zero, zvichiratidza kuti hapana 'magineti' akafanana nemagetsi. Unoratidzwa se:
\[
\nabla \cdot \mathbf{B} = 0
\]
3. Mutemo waFaraday weKupinza: Mutemo uyu unotsanangura kuti simba remagineti rinochinja-chinja nguva rinogadzira sei munda wemagetsi. Chimiro chemasvomhu ndeichi:
\[
\nabla \nguva \mathbf{E} = -\frac{\partial \mathbf{B}}{\partial t}
\]
4. Mutemo waAmpère (nekugadziriswa kwaMaxwell): Mutemo uyu unoti masimba emagineti anogadzirwa nemagetsi uye shanduko mumunda wemagetsi. Unopiwa na:
\[
\nabla \nguva \mathbf{B} = \mu_0 \mathbf{J} + \mu_0 \epsilon_0 \frac{\partial \mathbf{E}}{\partial t}
\]
apo \(\mathbf{J}\) iri huwandu hwezvino, uye \(\mu_0\) iri kubvumidzwa kwenzvimbo yakasununguka.
Kubviswa kweWave Equation
Kubva muequations dzaMaxwell, munhu anogona kuwana equation yemafungu emagetsi. Nekutora curl yeMutemo waFaraday woiisa muMutemo waAmpère, uku tichifunga kuti hapana ma free charges nema currents, tinowana:
\[
\nabla \nguva (\nabla \nguva \mathbf{E}) = – \frac{\ partial (\nabla \nguva \mathbf{B})}{\ partial t}
\]
Kushandisa vector identity \(\nabla \nguva (\nabla \nguva \mathbf{E}) = \nabla (\nabla \cdot \mathbf{E}) - \nabla^2 \mathbf{E}\) uye mutemo waGauss wemagetsi (\(\nabla \cdot \cdot \mathbf{E)), togona kurerutsa{E} =
\[
\nabla^2 \mathbf{E} = \mu_0 \epsilon_0 \frac{\partial^2 \mathbf{E}}{\partial t^2}
\]
Iyi ndiyo equation yemafungu yemagetsi. Maitiro akafanana anogona kushandiswa kuwana equation yemafungu yemagetsi, \(\mathbf{B}\). Aya mafungu equations anotsanangura kuti mafungu emagetsi anopararira sei muchadenga.
Hunhu hweMafungu eElectromagnetic
Mafungu emagetsi ane simba remagetsi nemagineti anotenderera akatarisana uye akananga kunobva mafungu. Zvikamu zvemagetsi (E) nemagetsi (B) zviri muchikamu uye zvinotenderera sinusoidal. Hunhu uhwu hwemafungu emagetsi neB hunoreva kuti mafungu emagetsi mafungu anotenderera.
Kumhanya kwemafungu emagetsi ari mu vacuum, kunoratidzwa ne \(c\), kunopiwa ne:
\[
c = \frac{1}{\sqrt{\mu_0 \epsilon_0}}
\]
Mhedzisiro iyi inoshamisa inoratidza kuti kumhanya kwechiedza mu vacuum chinhu chakakosha chechinhu ichi, chakabatana nekubvumidzwa uye kubvumidzwa kwenzvimbo yakasununguka. Mu vacuum, c inenge \(3 \times 10^8 \text{m/s}\).
Spectrum yeMafungu eElectromagnetic
Mafungu emagetsi anosanganisira mafrequency akasiyana-siyana uye ma wavelengths, zvichigadzira electromagnetic spectrum. Iyi spectrum inosanganisira marudzi akasiyana-siyana emafungu, kubva kumafungu eredhiyo ane frequency yakaderera kusvika kune ma gamma rays ane frequency yakakwirira. Mafungu aya anowanzo kamurwa kuita nzvimbo zvichienderana newavelength uye frequency, kusanganisira (mukutevedzana kwekuwedzera kwefrequency): mafungu eredhiyo, ma microwave, infrared radiation, chiedza chinoonekwa, ultraviolet radiation, ma X-ray, uye gamma rays.
Dunhu rega rega re spectrum rine hunhu hwakasiyana uye mashandisirwo aro. Semuenzaniso, mafungu eredhiyo anoshandiswa pakutaurirana, ma microwave ekushandisa radar nekubika, infrared yekutora mifananidzo yekupisa, chiedza chinoonekwa chekuona kwevanhu, chiedza che ultraviolet chekubvisa utachiona, ma X-ray ekutora mifananidzo yezvekurapa, uye gamma rays yekurapa kenza.
Polarization
Polarization zvinoreva kurongeka kwemagetsi emagetsi emagetsi emagetsi. Mumafungu ane polarized linearly, magetsi anotenderera mudenderedzwa rimwe chete. Polarization yakatenderera inoitika kana magetsi emagetsi achitenderera mudenderedzwa sezvo mafungu achipararira. Polarization ye elliptical inyaya yakajairika apo magetsi anobuda mudenderedzwa.
Kupatsanurana kwechiedza chinhu chakakosha mukuona nekutaurirana. Semuenzaniso, magirazi ezuva anopatsanurana anovhara mamwe maratidziro emafungu echiedza kuderedza kupenya, uye maantenna akagadzirwa kuti aenderane nekupatsanurana kwemasaini anotumirwa uye anogamuchirwa kuti akwanise kutaurirana zvinobudirira.
Kufungisisa, Kupatsanura, uye Kupatsanura
Mafungu emagetsi anosangana nezvinhu kuburikidza nemaitiro akadai sekufungisisa, kupenya, uye kupenya. Kufungisisa kunoitika kana mafungu asangana nemuganhu uye odzokera shure. Kupenya kunoreva kukotama kwemafungu sezvaanopfuura kubva kune imwe nzira kuenda kune imwe ine hunhu hwakasiyana, hunoratidzwa neSnell's Law. Kupatsanurwa kunosanganisira kupararira kwemafungu akakomberedza zvipingamupinyi uye kuburikidza nemaburi, ayo anonyanya kuoneka kune marefu ewavelengths.
mhedziso
Dzidziso huru yemafungu emagetsi, yakavakirwa muequations dzaMaxwell, inopa hwaro hwekunzwisisa maitiro uye mashandisirwo emafungu aya. Dzidziso idzi dzinotsanangura kupararira kwemafungu emagetsi, kumhanya kwawo, uye kudyidzana kwawo nezvinhu, pakati pezvimwe zvinhu. Kuziva pfungwa idzi dzakakosha pakusimudzira tekinoroji uye kuwedzera kunzwisisa kwedu nyika yechisikigo.
