Znaš kada se tvoj telefon prikači na magnetni držač u... Show more
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Updated May 15, 2026
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Magnetno Polje i Električna Struja
1 / 8
Erstedov eksperiment i osnove
Erstedov ogled je bio jednostavan, ali revolucionaran. Kada je pustio struju kroz žicu, igla kompasa u blizini se pomerila! To je dokazalo da struja stvara magnetno polje oko sebe.
Magnetno polje je nevidljivi prostor oko provodnika gde deluju magnetne sile. Možeš ga "videti" pomoću kompasa ili opiljaka gvožđa. Linije sila su zamišljene linije koje pokazuju kako polje "teče" - gušće linije znače jače polje.
Ključna stvar: Magnetno polje postoji SAMO dok struja teče. Čim isključiš struju, polje nestaje odmah!
💡 Zapamti: Ovo je osnova rada svih elektromagneta - mogu se uključivati i isključivati!
Magnetno polje pravog provodnika
Oko prave žice sa strujom nastaju kružne linije magnetnog polja. Linije su koncentrični krugovi koji okružuju žicu.
Da odrediš smer polja, koristi pravilo desne ruke za prav provodnik: ispruži palac u smeru struje, a savijeni prsti će pokazati smer magnetnog polja oko žice.
Ovo pravilo ti je neophodno za sve zadatke! Uvek prvo pronađi smer struje (od plusa ka minusu baterije), zatim primeni pravilo.
💡 Za test: Struja teče od pozitivnog ka negativnom polu baterije kroz spoljašnji deo kola!
Solenoid - kalem kao magnet
Solenoid je žica namotana u spiralu, i kada kroz njega teče struja - bum, imaš pravi magnet! Unutar kalema polje je jako i ujednačeno, a spolja liči na obični šipkasti magnet.
Solenoid ima severni (N) i južni (S) pol, baš kao stalni magnet. Da odredišpolare, koristi pravilo desne ruke za solenoid: obuhvati kalem tako da prsti prate smer struje, a palac će pokazati severni pol.
Razlika je što elektromagnet radi samo dok ima struje - isključiš struju, nestane magnetizam!
💡 Pametno: Elektromagneti su bolje od stalnih magneta jer možeš kontrolisati kada rade!
Jačina elektromagneta
Najbolja stvar kod elektromagneta je što možeš kontrolisati koliko su jaki! Jačina zavisi od tri faktora:
Jača struja = jače magnetno polje. Više navojaka žice = jače polje. Gvozdeno jezgro unutar kalema = mnogo jače polje od vazduha.
Ova kontrola čini elektromagnete super korisnim. U kranovima za metal, elektromagnetno kačenje telefona, zvučnicima - svuda gde trebaš da "uključiš" ili "isključiš" magnetizam.
💡 Praktično: Električna zvona rade tako što elektromagnet privlači metalnu pločicu koja udara u zvono!
Primeri i pravila za zadatke
Prvi korak u svakom zadatku: odredi smer struje u kolu! Struja uvek teče od pozitivnog ka negativnom polu baterije kroz spoljašnji deo.
Za prav provodnik: palac u smeru struje, prsti pokazuju smer polja oko žice. Za solenoid: prsti prate struju u navojcima, palac pokazuje severni pol.
Ne mešaj pravila! Postoje dva različita pravila desne ruke i svako ima svoju ulogu.
💡 Trik za uspeh: Uvek nacrtkaj smer struje pre nego što primeniš bilo koje pravilo!
Pregled za test
Osnove: Svaka struja pravi magnetno polje (Ersted). Polje postoji samo dok struja teče.
Prav provodnik: Kružno polje oko žice. Solenoid: Ponašaju se kao šipkasti magneti sa N i S polovima.
Jačina elektromagneta: Zavisi od struje, broja navojaka i gvožđa u sredini. Pravila desne ruke: Različito za žicu i kalem - ne mešaj ih!
💡 Za odličnu ocenu: Vežbaj određivanje smerova - to je ono što se najčešće pita na testu!
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Magnetno Polje i Električna Struja
Znaš kada se tvoj telefon prikači na magnetni držač u kolima? To radi zahvaljujući vezi između struje i magnetizma! Danski naučnik Ersted je pre 200 godina slučajno otkrio da električna struja stvara magnetno polje - i ta veza je osnova... Show more
Erstedov eksperiment i osnove
Erstedov ogled je bio jednostavan, ali revolucionaran. Kada je pustio struju kroz žicu, igla kompasa u blizini se pomerila! To je dokazalo da struja stvara magnetno polje oko sebe.
Magnetno polje je nevidljivi prostor oko provodnika gde deluju magnetne sile. Možeš ga "videti" pomoću kompasa ili opiljaka gvožđa. Linije sila su zamišljene linije koje pokazuju kako polje "teče" - gušće linije znače jače polje.
Ključna stvar: Magnetno polje postoji SAMO dok struja teče. Čim isključiš struju, polje nestaje odmah!
💡 Zapamti: Ovo je osnova rada svih elektromagneta - mogu se uključivati i isključivati!
Sign up to see the contentIt's free!
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Magnetno polje pravog provodnika
Oko prave žice sa strujom nastaju kružne linije magnetnog polja. Linije su koncentrični krugovi koji okružuju žicu.
Da odrediš smer polja, koristi pravilo desne ruke za prav provodnik: ispruži palac u smeru struje, a savijeni prsti će pokazati smer magnetnog polja oko žice.
Ovo pravilo ti je neophodno za sve zadatke! Uvek prvo pronađi smer struje (od plusa ka minusu baterije), zatim primeni pravilo.
💡 Za test: Struja teče od pozitivnog ka negativnom polu baterije kroz spoljašnji deo kola!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
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Solenoid - kalem kao magnet
Solenoid je žica namotana u spiralu, i kada kroz njega teče struja - bum, imaš pravi magnet! Unutar kalema polje je jako i ujednačeno, a spolja liči na obični šipkasti magnet.
Solenoid ima severni (N) i južni (S) pol, baš kao stalni magnet. Da odredišpolare, koristi pravilo desne ruke za solenoid: obuhvati kalem tako da prsti prate smer struje, a palac će pokazati severni pol.
Razlika je što elektromagnet radi samo dok ima struje - isključiš struju, nestane magnetizam!
💡 Pametno: Elektromagneti su bolje od stalnih magneta jer možeš kontrolisati kada rade!
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Jačina elektromagneta
Najbolja stvar kod elektromagneta je što možeš kontrolisati koliko su jaki! Jačina zavisi od tri faktora:
Jača struja = jače magnetno polje. Više navojaka žice = jače polje. Gvozdeno jezgro unutar kalema = mnogo jače polje od vazduha.
Ova kontrola čini elektromagnete super korisnim. U kranovima za metal, elektromagnetno kačenje telefona, zvučnicima - svuda gde trebaš da "uključiš" ili "isključiš" magnetizam.
💡 Praktično: Električna zvona rade tako što elektromagnet privlači metalnu pločicu koja udara u zvono!
Sign up to see the contentIt's free!
Access to all documents
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Primeri i pravila za zadatke
Prvi korak u svakom zadatku: odredi smer struje u kolu! Struja uvek teče od pozitivnog ka negativnom polu baterije kroz spoljašnji deo.
Za prav provodnik: palac u smeru struje, prsti pokazuju smer polja oko žice. Za solenoid: prsti prate struju u navojcima, palac pokazuje severni pol.
Ne mešaj pravila! Postoje dva različita pravila desne ruke i svako ima svoju ulogu.
💡 Trik za uspeh: Uvek nacrtkaj smer struje pre nego što primeniš bilo koje pravilo!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
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Pregled za test
Osnove: Svaka struja pravi magnetno polje (Ersted). Polje postoji samo dok struja teče.
Prav provodnik: Kružno polje oko žice. Solenoid: Ponašaju se kao šipkasti magneti sa N i S polovima.
Jačina elektromagneta: Zavisi od struje, broja navojaka i gvožđa u sredini. Pravila desne ruke: Različito za žicu i kalem - ne mešaj ih!
💡 Za odličnu ocenu: Vežbaj određivanje smerova - to je ono što se najčešće pita na testu!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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4.6/5
App Store
4.7/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user