Chitsanzo cha funso lokambirana za kukula kwa EMF yoyambitsidwa
Pendauluan
Mphamvu yoyendetsedwa ndi ma electromotive (EMF) ndi chinthu chomwe chinapezeka ndi Michael Faraday mu 1831. Faraday adapeza kuti mphamvu ya maginito yosintha mu loop kapena coil ya conductor ingayambitse magetsi. Chinthuchi chimatchedwa electromagnetic induction ndipo ndicho maziko a matekinoloje ambiri amakono, monga majenereta, ma transformer, ndi ma motors amagetsi. Nkhaniyi ifotokoza mavuto angapo a zitsanzo ndikukambirana za kukula kwa EMF yoyendetsedwa, yomwe idzakhala yothandiza kwambiri makamaka kwa ophunzira omwe amaphunzira sayansi yamagetsi ndi maginito.
Lingaliro Loyambira la EMF Yoyambitsidwa
Tisanafufuze bwino nkhaniyi, ndi bwino kubwerezanso mfundo yoyambira ya induced emf. Lamulo la Faraday limati induced emf mu conducting loop imagwirizana mwachindunji ndi kuchuluka kwa kusintha kwa magnetic flux kudzera mu loop. Mwa masamu, lamulo la Faraday lingapangidwe motere:
\[ \mathcal{E} = – \frac{d\Phi}{dt} \]
Kumene:
– \( \mathcal{E} \) ndi EMF yoyambitsidwa (volts)
– \( \Phi \) ndi maginito otuluka (Weber, Wb)
– \( t \) ndi nthawi (yachiwiri, s)
Chizindikiro chotsutsa mu equation chikuwonetsa Lamulo la Lenz lomwe limati njira ya mphamvu yoyambitsidwa idzapanga mphamvu yamaginito yomwe imatsutsa kusintha kwa mphamvu yamaginito yomwe idayambitsa.
Mafunso ndi Kukambirana Zitsanzo
Funso 1: Chozungulira Chimodzi
Funso: Chozungulira chimodzi chokhala ndi malo okwana 0.02 m² chimayikidwa mu mphamvu ya maginito yofanana ya kukula kwa 0.5 T, yolunjika pamwamba pa chozungulira. Mphamvu ya maginito imachotsedwa mwadzidzidzi mu masekondi 0.1. Werengani kukula kwa EMF yomwe imabwera mu chozunguliracho.
Kukambirana:
Ndizodziwika kuti:
– Malo ozungulira a coil (A = 0.02, text{m}^2)
– Kukula kwa mphamvu ya maginito \( B = 0.5 \, \text{T} \)
– Nthawi yosinthira munda \( \Delta t = 0.1 \, \text{s} \)
Kusintha kwa mphamvu ya maginito:
\[ \Delta \Phi = B \times A \]
\[ \Delta \Phi = 0.5 \, \text{T} \times 0.02 \, \text{m}^2 \]
\[ \Delta \Phi = 0.01 \, \malemba{Wb} \]
Kukula kwa EMF komwe kumayambitsidwa:
\[ \masamu{E} = – \frac{\Delta \Phi}{\Delta t} \]
\[ \mathcal{E} = – \frac{0.01 \, \text{Wb}}{0.1 \, \text{s}} \]
\[ \ masamu{E} = -0.1 \, \lemba{V} \]
Chifukwa chomwe chikufunsidwa ndi kukula kwa EMF (popanda kulabadira chizindikirocho):
\[ |\masamu{E}| = 0.1 \, \lemba{V} \]
Funso 2: Koyilo yokhala ndi N Turns
Funso: Chokochi chimakhala ndi ma turn 100 ndipo malo ake pamwamba ndi 0.03 m². Chokochichi chili mu mphamvu ya maginito yofanana ya 0.4 T perpendicular kwa chokochi. Ngati mphamvu ya maginito iwonjezeka kufika pa 1.2 T mu masekondi 0.4, werengani avareji ya emf yomwe imapangidwa mu chokochi.
Kukambirana:
Ndizodziwika kuti:
– Chiwerengero cha ma turns \( N = 100 \)
– Malo ozungulira a coil (A = 0.03, text{m}^2)
– Kusintha kwa mphamvu ya maginito \( \Delta B = 1.2 \, \text{T} – 0.4 \, \text{T} \)
– Nthawi yosinthira munda \( \Delta t = 0.4 \, \text{s} \)
Kusintha kwa mphamvu ya maginito pa kuzungulira kulikonse:
\[ \Delta \Phi = A \times \Delta B \]
\[ \Delta \Phi = 0.03 \, \text{m}^2 \times (1.2 \, \text{T} – 0.4 \, \text{T}) \]
\[ \Delta \Phi = 0.03 \, \text{m}^2 \times 0.8 \, \text{T} \]
\[ \Delta \Phi = 0.024 \, \malemba{Wb} \]
Kusintha konse kwa ma flux a N:
\[ \Delta \Phi_{\text{total}} = N \times \Delta \Phi \]
\[ \Delta \Phi_{\text{total}} = 100 \nthawi 0.024 \, \text{Wb} \]
\[ \Delta \Phi_{\text{total}} = 2.4 \, \text{Wb} \]
Kukula kwa EMF komwe kumayambitsidwa:
\[ \mathcal{E} = – \frac{\Delta \Phi_{\text{total}}}{\Delta t} \]
\[ \mathcal{E} = – \frac{2.4 \, \text{Wb}}{0.4 \, \text{s}} \]
\[ \ masamu{E} = -6 \, \lemba{V} \]
Chifukwa chomwe chikufunsidwa ndi kukula kwa EMF (popanda kulabadira chizindikirocho):
\[ |\masamu{E}| = 6 \, \lemba{V} \]
Funso 3: Kusuntha Koyilo mu Magnetic Field
Funso: Chozungulira chamakona anayi chokhala ndi ma turns 50, kutalika kwa 4 cm, ndi mulifupi wa 2 cm, chimayikidwa mu mphamvu ya maginito yofanana ya 0.3 T yofanana ndi kutalika kwa chozungulira. Ngati chozunguliracho chikutuluka mu mphamvu ya maginito pa liwiro losasintha la 5 cm/s, kodi EMF yomwe imayambitsa mu chozunguliracho ndi chiyani?
Kukambirana:
Ndizodziwika kuti:
– Chiwerengero cha ma turns \( N = 50 \)
– Kutalika \( l = 0.04 \, \text{m} \)
– M'lifupi \( w = 0.02 \, \text{m} \)
– Kukula kwa mphamvu ya maginito \( B = 0.3 \, \text{T} \)
– Liwiro lotulukira la mphamvu ya maginito \( v = 0.05 \, \text{m/s} \)
Mphamvu yamagetsi pa coil yomwe ikuyenda mu magnetic field imaperekedwa ndi:
\[ \mathcal{E} = B lv \]
Popeza coil ili ndi ma N turns, EMF yonse yomwe imayambitsa ndi:
\[ \mathcal{E}_{\text{total}} = NB lv \]
\[ \mathcal{E}_{\text{total}} = 50 \times 0.3 \, \text{T} \times 0.04 \, \text{m} \times 0.05 \, \text{m/s} \]
\[ \mathcal{E}_{\text{total}} = 50 \nthawi 0.0006 \, \text{V} \]
\[ \masamu{E}_{\mawu{chiwerengero}} = 0.03 \, \mawu{V} \]
Mapeto
Kukambirana za mavuto omwe ali pamwambapa kukuwonetsa momwe emf yoyambitsidwa ingawerengeredwere kuchokera ku kusintha kwa maginito kapena kuchokera ku kayendedwe ka coil mu mphamvu ya maginito. Lingaliro ili ndi lofunikira kwambiri pa zamagetsi ndipo limagwiritsidwa ntchito m'njira zambiri muukadaulo. Kumvetsetsa momwe mungawerengere emf yoyambitsidwa molondola kudzera mumavuto ogwira ntchito kudzathandiza kwambiri ophunzira kudziwa bwino izi ndikuzigwiritsa ntchito m'magawo osiyanasiyana.
