FIZIC *F* FE. ELECTROMAGNETISM

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FE.

ELECTROMAGNETISM

FIZIC *F* FE. ELECTROMAGNETISM

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CUPRINS

Cuvnt inainte ................................................................................................................................................ 3 FE.01. Electrostatica. Sarcini i cmpuri........................................................................................................ 5

FE.01.1. Introducere............................................................................................................................ 5 FE.01.2. Structura materiei................................................................................................................. 5 FE.01.3 Conservarea sarcinii electrice............................................................................................... 5 FE.01.4. Cuantificarea sarcinii electrice............................................................................................. 6 FE.01.5. Legea lui Coulomb........... 6 FE.01.6. Distribuii de sarcin. Densitatea de sarcin ........... 7

FE.02. Cmpul electric ....................... 8 FE.02.1. Cmpul electric .................................................................................................................... 8 FE.02.2. Liniile cmpului electric ...................................................................................................... 10 FE.02.3. Fluxul cmpului electric .................................................................................................... 11 FE.02.4. Legea lui Gauss.................................................................................................................... 12 FE.02.5. Lucrul mecanic efectuat de fora cmpului electric............................................................ 13 FE.02.6. Potenialul cmpului electric ............................................................................................... 14 FE.02.7. Cmpul electric al dipolului electric .................................................................................... 15 FE.02.8. Relaia dintre cmp i potenial .......................................................................................... 17 FE.02.9. Capacitatea electric ........................................................................................................... 18 FE.02.10. Polarizarea electric. Vectorul inducie electric............................................................... 19 FE.02.11. Energia cmpului electric................................................................................................... 26 FE.02.12. Aplicaii multimedia .......................................................................................................... 27 FE.03. Curentul electric................................................................................................................................. 29 FE.03.1. Curentul electric .................................................................................................................. 29 FE.03.2. Intensitatea curentului electric ............................................................................................ 30 FE.03.3. Densitatea de curent ............................................................................................................. 30 FE.03.4. Purttorii de sarcin n metale......................................... 32 FE.03.5 Legea lui Ohm....................................................................................................................... 32 FE.03.6. Benzi de energie. Conductori. Semiconductori...................................................... 35 FE.03.7. Circuite de curent continuu ............................................................................. 38 FE.03.8.Aplicarea legii lui Ohm..................................................................................................... 39 FE.03.9. Circuite electrice ramificate. Legile lui Kirchoff............................................................ 41 FE.03.10. C Aplicaii multimedia.................................................................................................. 43 FE.04. Cmpul magnetic............................................................................................................................... 44 FE.04.1. Cmpul magnetic. Fore magnetice ................................................................................... 44 FE.04.2. Intensitatea cmpului magnetic ........................................................................................... 44 FE.04.3. Caracterul vectorial al cmpului magnetic .......................................................................... 45 FE.04.4. Liniile cmpului magnetic ....................... 47 FE.04.5. Fluxul cmpului magnetic .. 47 FE.04.6. Aciunea cmpului magnetic asupra curentului electric .. 48 FE.04.7. Sursele cmpului magnetic .................................................................................................. 51 FE.04.8. Legea Biot-Savart ....................... 51 FE.04.9. Cmpul magnetic n centrul unei spire ....................... 52 FE.04.10. Cmpul magnetic al unui curent rectiliniu infinit lung .................................... 53 FE.04.11. Legea lui Ampre ...................... 54 FE.04.12. Amperul - unitate fundamental n SI ............................................................... 55 FE.04.13. Legea lui Gauss pentru magnetism ................................................................................... 56 FE.04.14. Aplicaii ale cmpului magnetic ....................................................................................... 57 FE.04.15. Aplicaii multimedia.......................................................................................................... 61 FE.05. Proprieti magnetice ale substanei................................................................................................... 63 FE.05.1. Momentul magnetic atomic.................................................................................................. 63 FE.05.2. Intensitatea de magnetizare................................................................................................. 64 FE.05.3. Cmpul magnetic ................................................................................................................. 65

FIZIC *F* FE. ELECTROMAGNETISM

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FE.05.4. Susceptibilitatea magnetic ................................................................................................. 66 FE.05.5. Clasificarea substanelor dup proprietile magnetice....................................... 67 FE.05.6. Aplicaii multimedia ............................................................................................................ 76 FE.06. Fenomene electromagnetice variabile in timp .................................................................................. 77 FE.06.1. Inducia electromagnetic ................................................................................................... 77 FE.06.2. Legea Faraday-Lenz ........................................................................................................... 77 FE.06.3. Natura tensiunii electromotoare induse .............................................................................. 79 FE.06.4. Inducia mutual.................................................................................................................. 80 FE.06.5. Autoinducia Inducia electromagnetic ............................................................................. 82 FE.06.6. Curentul de deplasare........................................................................................................... 84 FE.06.7. Inducia magnetoelectric ................................................................................................... 85 FE.06.8. Ecuaiile lui Maxwell 85 FE.06.9. Aplicaii multimedia ........................................................................................................... 86 FE.07. Unde electromagnetice ...................................................................................................................... 88 FE.07.1. Producerea undelor electromagnetice................................................................................... 88 FE.07.2. Cmpul electromagnetic. Unde electromagnetice................................................................ 89 FE.07.3. Ecuaia undelor plane sinusoidale...................................................................................... 91 FE.07.4. Ecuaia de propagare a undelor electromagnetice ............................................................... 92 FE.07.5. Viteza de propagare a undelor electromagnetice ................................................................. 94 FE.07.6. Energia cmpului electric ................................................................................................... 95 FE.07.7. Energia cmpului magnetic ................................................................................................ 95 FE.07.8. Energia i impulsul undelor electromagnetice.................................................................... 97 FE.07.9. Clasificarea undelor electromagnetice ................................................................................ 100 FE.07.10. Aplicaii multimedia ......................................................................................................... 103 FE.09. Aplicaii de laborator ......................................................................................................................... 105 FE.09.1. Determinarea sarcinii specifice a electronului din legea lui Langmuir................................ 105 FE.09.2. Masurarea capacitatilor si inducta