PH2200 Formula Sheet - Electric Charges, Fields, and Circuits Summary

Nov 2, 2026

PH2200公式汇总覆盖电荷与力、电场与电势、并联与串联电容、电路与电流密度、以及磁场与电磁感应等核心物理内容。内容包含库仑力与高斯定律相关的通量表达、平行板电容与理想电池的电势差关系、串并联等效电阻/电容推导、欧姆与回路/节点定律应用。还给出安培/右手定则下磁场公式、法拉第电磁感应与麦克斯韦相关的场—波关系表达，并整理若干物理常数与几何公式。

LanguageEnglish

CategoryTechnology

FormatPDF

Pages2

Reading Time5 min

AccessFree to download

Electric Charges and Forces

The Electric Field

The Electric Potential

Gauss’s Law

Capacitors and Current

Parallel-plate Capacitor

Current and Conductivity

Fundamentals of Circuits

The Magnetic Field

Magnetic Forces

Electromagnetic Induction

Electromagnetic Fields and Waves

Physical Constants and Useful Geometry

PH2200 Formula Sheet Knight Electric Charges and Forces K q1 q2 F = F = ~~ ~~1 on 2 2 on 1 2 r q = ( Np − Ne ) e GE = GFon q / q G G Fon B = qBE GE = 41πε0~~ ~~qr~~ ~~2~~ ~~ point charge The Electric Field GEnet = ∑i GEi Electric dipole: -q G p s - + +q Gp = ( qs, from negative to positive ) Field on axis GE = ~~ ~~41πε0~~ ~~2r Field in bisecting plane GE =− ~~ ~~41πε0~~ ~~ linear charge density : λ = ~~ ~~QL surface charge density : η = ~~ ~~QA volume charge density : ρ = ~~ ~~QV Uniform infinite line of charge: G ⎛ 1 2 λ ⎞ E = ⎜ , perpendicular to line ⎟ ⎝ 4πε0 r ⎠ Uniform infinite plane of charge: GE = ⎛⎜ η , perpendicular to plane⎞⎟⎝ 2ε0 ⎠ Uniformly charged sphere: GE = ~~ ~~4πQε~~ ~~0r~~ ~~2~~ ~~ for r ≥ R Parallel-plate capacitor: G ⎛ ⎞ E = ⎜ η , from positive to negative ⎟⎝ ε0 ⎠ ( Ering )z ( Edisk )z Ga = ( q / 1 zQ = 4πε0 ( z 2 + R2 )3/ 2 η ⎡ z ⎤= 2ε0 ⎢⎣1 − z 2 + R2 ⎦⎥ m ) GE τ = pE sinθ Gauss’s Law Φ e = GE ⋅ GA = EAcosθ constant field Φ e = ∫ GE ⋅ dGA surface Φ e = GE ⋅ dGA = ~~ ~~Qε~~i~~n0~~ ~~ GE at surface of a charged conductor:⎧ η ⎪ Esurface = ⎨ ε0 ⎪⎩perpendicular to surface The Electric Potential Uelect = U0 + qEs (parallel-plate capacitor) U 1 2 = 1 q1q2 Uelect = ∑ 1 qiqj q +q 4πε0 r iper turn | | --- | | dt | Ecoil = ωABNsin ωt V = N2 V 2 1 N1 Electromagnetic Fields and Waves GE ⋅ dGA = ~~ ~~Qε~~i~~n0~~ ~~ GB ⋅ dGA = 0 GE ⋅ dGs = − ~~ ~~dΦdtm GB ⋅ dGs = μ0Ithrough + ε0 μ0 ~~ ~~dΦdte~~ ~~GF = q ( GE + Gv × GB) Idisp = ε0 ~~ ~~dΦdte~~ ~~vem = c = 1/ ε0 μ0 c = λf E = cB GS = ~~ ~~1μ0~~ ~~ ( GE × GB) I = P = S = 1 E 2 = cε0 E 2 A avg 2cμ0 0 2 0 prad = ~~ ~~FA = Ic~~ ~~ (perfect absorber) I = I0 cos2 θ Itransmitted = ~~ ~~12 I0 (incident light unpolarized) Physical Constants K = 8.99 × 109 N ⋅ m2 /C2 ε0 = 8.85 × 10−12 C2 /N ⋅ m2 e = 1.60 × 10−19 C me = 9.11 × 10−31 kg mp = 1.67 × 10−27 kg μ0 = 1.26 × 10−6

FAQs

电场与电势差在平行板电容中如何关联？

文档给出平行板电容的电场与电势差关系：V（由E与板间距离或等效表达式表示），并结合UeIect与U0/qEs的形式描述电势能变化。

如何使用高斯定律计算电场通量？

文档写出电场通量与积分形式：Φe 与 ∫GE·dGA 的关系，并给出带电导体表面电场方向与法向分量的表达。

电磁感应与电磁波之间的关键关系是什么？

文档给出感应电动势E与磁通变化率dΦ/dt相关的式子，并在后续列出电磁场与波动关系（例如c=λf、E=cB），体现场与波的耦合。

Nov 2, 2026

Uploaded by Jordan Avery