YPermittivity vs Permeability
Permeability thiab Permittivity yog ob lub ntsiab lus pom hauv electromagnetic txoj kev xav tsim los ntawm James Clark Maxwell. Lawv yog cov ntsiab lus sib npaug qhov twg permittivity yog siv nyob rau hauv hluav taws xob teb thiab permeability yog siv nyob rau hauv lub magnetic teb.
Permittivity (ε)
Permittivity yog ib qho kev ntsuas ntawm qhov kev tawm tsam hauv kev tsim hluav taws xob los ntawm qhov nruab nrab. Nws txhais tau tias yog qhov sib piv ntawm qhov hluav taws xob hloov chaw (D) hauv qhov nruab nrab thiab qhov siv hluav taws xob ua rau nws (E). Nws yog ib qho tseem ceeb ntawm hluav taws xob parameter ntawm cov ntaub ntawv, tshwj xeeb tshaj yog nyob rau hauv cov ntaub ntawv ntawm insulators.
ε=D/E
Permittivity yog ntsuas nyob rau hauv Farads ib meter (Fm-1), nyob rau hauv lub thoob ntiaj teb system ntawm units.
Qhov permittivity ntawm qhov nruab nrab piav qhia txog tus nqi ntawm flux generated ib chav tsev nqi hauv nruab nrab. Qhov siab permittivity qhia tau hais tias tus nqi siab ntawm polarization nyob rau hauv nruab nrab thiab ntau hluav taws xob flux los tsim cov hluav taws xob tawm tsam. Yog li ntawd, lub net teb lub zog nyob rau hauv ib tug dielectric nruab nrab yog tsawg yog lub permittivity siab.
Permittivity nyob rau hauv lub tshuab nqus tsev yog qhov tas mus li thiab yog qhov tsawg tshaj plaws permittivity. Nqus permittivity yog denoted los ntawm ε0, thiab muaj nqis 8.854 × 10-54 Fm-1 Qee zaus Nws yog qhov yooj yim los muab qhov permittivity ntawm dielectric nruab nrab raws li ntau yam ntawm lub tshuab nqus tsev permittivity uas tso cai rau kev siv lej yooj yim thiab kev sib piv ntawm qhov permittivity ntawm cov xov xwm sib txawv. Relative permittivity yog qhov piv ntawm qhov tseeb permittivity thiab lub tshuab nqus tsev permittivity. Permittivity Absolute (ε) yog qhov permittivity tiag tiag ntawm nruab nrab.
εr=ε/ε0 thiab yog li ε=εr ε 0
Kev txheeb ze permittivity tsis muaj units thiab ib txwm ntau dua 1.
Permittivity yog ze ze rau qhov cuam tshuam ntawm qhov nruab nrab, uas yog qhov ntsuas ntawm qhov yooj yim ntawm polarization ntawm dipoles hauv nruab nrab. Yog hais tias qhov susceptibility ntawm nruab nrab yog χ, ε=εr ε0 =(1+χ) ε0 thiab li no (1+χ)=εr
Permeability (µ)
Permeability yog ib qho kev ntsuas ntawm cov khoom muaj peev xwm los tsim cov hlau nplaum hauv nws. Nws txhais tau tias yog qhov sib piv ntawm qhov sib nqus qhov sib nqus (B) hauv nruab nrab thiab sab nraud magnetic teb lub zog (H). Nws yog ib qho khoom tseem ceeb thaum xav txog cov khoom sib nqus ntawm cov khoom.
µ=B/H
SI unit of Permeability is Henry per meter (Hm-1). Permeability yog scalar kom muaj nuj nqis.
Permeability kuj tuaj yeem piav qhia raws li qhov inductance ib chav tsev ntev. Nws piav qhia txog qhov sib nqus flux tsim nyob rau hauv nruab nrab thaum siv cov hlau nplaum sab nraud. Yog hais tias tus tsim flux txhawb rau sab nraud teb, nws yog hu ua paramagnetism. Yog hais tias lub flux tawm tsam sab nraud, ces nws hu ua diamagnetism.
Qhov permeability nyob rau hauv qhov chaw dawb (nqus) yog qhov tsawg tshaj plaws permeability, thiab nws cov nqi yog 1.2566 × 10-6 Hm-1los yog NA-2 Ib yam li hauv permittivity, nws yooj yim los txhais cov txheeb ze permeability. Cov lus qhia rau txheeb ze permeability yog raws li nram no:
µr=µ/µ0
Magnetic susceptibility yog ib qho kev ntsuas ntawm qhov magnetization ntawm cov khoom, ntxiv rau qhov magnetization ntawm qhov chaw nyob los ntawm cov khoom, thiab nws yog denoted los ntawm χ mthiab nws yog ib dimensionless kom muaj nuj nqis.
µ=µr µ0 =(1+χm) µ 0 thiab li no (1+χm)=µr
Qhov txawv ntawm Permittivity thiab Permeability yog dab tsi?
• Permittivity thiab permeability yog ob lub ntsiab lus pom hauv electromagnetic txoj kev xav. Permittivity cuam tshuam cov hluav taws xob thaum lub Permeability cuam tshuam cov magnetic teb. Lawv yog cov khoom zoo sib xws hauv electromagnetic teb.
• Permittivity txhais tau tias yog qhov piv ntawm qhov sib txawv ntawm qhov chaw tawm mus rau lub zog hluav taws xob, qhov permeability txhais tau tias yog qhov piv ntawm qhov sib nqus ntawm qhov sib nqus thiab qhov sib nqus lub zog.
• Cov nyiaj tso cai rau cov txiaj ntsig polarization hauv cov khoom thaum permeability tso nyiaj rau cov hlau nplaum ntawm cov khoom.
• Permeability yog ntsuas hauv Henry ib meter Hm-1, hos permittivity yog ntsuas hauv Farads ib meter Fm-1.
