Gauss Law vs Coulomb Law
Gauss txoj cai thiab Coulomb txoj cai yog ob txoj cai tseem ceeb uas siv hauv electromagnetic field theory. Cov no yog ob txoj cai tseem ceeb tshaj plaws, uas ua rau txoj kev loj hlob ntawm electromagnetic teb. Cov cai no, nrog rau Ampere txoj cai, ua rau Maxwell qhov sib npaug. Maxwell qhov sib npaug yog ib pawg ntawm plaub qhov sib npaug uas tuaj yeem piav qhia txhua qhov tshwm sim hauv electromagnetic txoj kev xav. Yuav tsum muaj kev nkag siab zoo hauv ob txoj cai no, kom nkag siab txog kev xav ntawm electromagnetism tag nrho. Hauv tsab xov xwm no, peb yuav tham txog dab tsi Gauss txoj cai thiab Coulomb txoj cai yog, lawv cov ntawv thov, cov ntsiab lus, qhov sib xws ntawm ob, thiab thaum kawg qhov sib txawv ntawm Gauss txoj cai thiab Coulomb txoj cai.
Gauss's Law
Gauss txoj cai yog ib txoj cai tseem ceeb heev uas piav txog cov khoom ntawm cov hluav taws xob, cov hlau nplaum thiab cov gravitational. Gauss txoj cai lij choj rau hluav taws xob teb hais tias hluav taws xob flux los ntawm txhua qhov chaw kaw yog sib npaug rau cov nqi hluav taws xob uas nyob ze ntawm qhov chaw. Nws tuaj yeem hais tau raws li ∅=Q/ε0 qhov twg φ yog tag nrho cov hluav taws xob flux hla saum npoo, Q yog tus nqi them los ntawm qhov chaw, thiab ε 0yog qhov dielectric tas li. Yuav kom nkag siab txog lub tswv yim no, ib tug yuav tsum xub to taub lub tswvyim ntawm hluav taws xob flux. Qhov hluav taws xob flux hla ib qhov chaw yog qhov ntsuas ntawm tus naj npawb ntawm cov kab hluav taws xob uas dhau los ntawm ib qho chaw. Qhov no yog ncaj qha proportional rau tus naj npawb ntawm cov kab hluav taws xob thoob plaws qhov chaw. Gauss txoj cai rau cov hlau nplaum yog ib txoj cai tseem ceeb heev. Gauss txoj cai lij choj rau cov hlau nplaum hais tias tag nrho cov hlau nplaum sib nqus ntawm txhua qhov chaw kaw yog xoom. Qhov no yog vim tsis muaj magnetic monopoles. Sib nqus ncej tsuas yog muaj raws li dipoles. Nyob rau hauv txhua qhov chaw kaw, qhov sib nqus sib nqus polarity yog xoom. Yog li ntawd, qhov sib nqus flux hla txhua qhov chaw kaw yog xoom.
Coulomb's Law
Coulomb txoj cai yog txoj cai piav qhia txog kev sib cuam tshuam ntawm cov khoom siv hluav taws xob. Qhov no hais tias lub zog nruab nrab ntawm ob qhov hluav taws xob uas muaj hluav taws xob yog proportional rau cov nqi thiab inversely proportional rau lub square ntawm qhov kev ncua deb ntawm ob hais. Qhov no tuaj yeem qhia tau siv qhov sib npaug F=Q1Q2/ 4πr2ε 0 qhov twg Q1 thiab Q2 yog cov nqi ntawm cov khoom, r yog qhov kev ncua deb ntawm ob tus nqi, thiab ε0yog qhov dielectric tas li ntawm qhov chaw dawb. Yog tias qhov sib npaug no txhais tau rau qhov nruab nrab uas tsis yog qhov chaw dawb, ε 0yuav tsum tau hloov nrog ε, qhov twg ε yog qhov dielectric qhov nruab nrab. Yog tias cov nqi no yog tib lub cim, F yuav yog tus nqi zoo. Qhov no txhais tau hais tias ob qho kev them nqi tau rov ua dua ib leeg. Yog tias ob qhov kev them nqi no muaj cov cim sib txawv, F yuav dhau los ua tus nqi tsis zoo; yog li no, piav txog qhov kev nyiam ntawm ob tus nqi.
Qhov txawv ntawm Coulomb txoj cai thiab Gauss txoj cai yog dab tsi?
• Coulomb txoj cai lij choj piav qhia txog kev sib cuam tshuam ntawm ob qhov kev them nqi thaum Gauss txoj cai piav qhia txog cov dej ntws tawm ntawm qhov chaw kaw los ntawm cov cuab yeej nyob hauv qhov chaw.
• Coulomb txoj cai tsuas yog siv tau rau thaj chaw hluav taws xob nkaus xwb thaum Gauss txoj cai siv tau rau hluav taws xob teb, sib nqus teb thiab gravitational fields.
