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The atlas of physics 94 laws · 382 quantities · 299 equations

Vrms voltage vmpeak voltage Irms current impeak current vm=2⋅V im=2⋅I νfrequency ωangular frequency Linductance Ccapacitance XLinductive reactance XCcapacitive reactance VLvoltage across the inductor VCvoltage across the capacitor πpi Irms current ω=2⋅π⋅ν XL=2⋅π⋅ν⋅L XC=12⋅π⋅ν⋅C VL=I⋅XL VC=I⋅XC Rresistance Ppower drawn Vrms voltage Irms current P=V2R V=I⋅R Rresistance Zimpedance Ppower drawn νrresonant frequency φphase angle ωrresonant angular frequency XLinductive reactance XCcapacitive reactance Vrms voltage Irms current πpi Linductance Ccapacitance Z2=R2+(XL-XC)2 V=I⋅Z P=I2⋅R φ=atan⁡(XC-XLR) νr=12⋅π⋅L⋅C ωr=2⋅π⋅νr
Zatomic number Kkinetic energy dclosest approach kcoulomb constant eelementary charge K=k⋅2⋅e⋅Z⋅ed mmass rorbit radius vorbital speed Ebbinding energy nquantum number Zatomic number Upotential energy Etotal energy Epphoton energy νfrequency kcoulomb constant eelementary charge πpi hplancks constant Eb=k⋅e22⋅r m⋅v2r=k⋅e2r2 v=2⋅π⋅k⋅Z⋅e2n⋅h m⋅v⋅r=n⋅h2⋅π U=−k⋅e2r E=−k⋅e22⋅r Ep=h⋅ν
Icurrent Across section ρdensity Mmolar mass nfree electrons vddrift speed llength of the conductor tdrift time NAavogadro constant eelementary charge n=ρ⋅NAM I=n⋅e⋅A⋅vd l=vd⋅t Vvoltage Icurrent Rresistance llength of the conductor Across section ρresistivity V=I⋅R R=ρ⋅lA αtemperature coefficient R₀reference resistance T₀reference temperature Ttemperature Rresistance R=R0⋅(1+α⋅(T-T0))
mmass vspeed λde broglie wavelength hplancks constant λ=hm⋅v φ₀work function ν₀threshold frequency V₀stopping potential Kmaxmaximum kinetic energy hplancks constant eelementary charge νfrequency h⋅ν0=φ0 e⋅V0=h⋅ν-φ0 e⋅V0=Kmax νfrequency λwavelength Ephoton energy pphoton momentum Pemitted power Nphotons a second Vaccelerating potential hplancks constant cspeed of light E=h⋅ν c=ν⋅λ p=hλ P=N⋅E
rseparation Feelectric force kcoulomb constant qcharge Fe=k⋅q1⋅q2r2 qcharge nnumber of charges ndotcharges a second tcharging time eelementary charge q=n⋅e n=ndot⋅t Efield strength rseparation Eqfield of a charge Fforce of the field qcharge kcoulomb constant F=q⋅E Eq=k⋅qr2 Efield strength Aarea rradius Φelectric flux qcharge inside Ddiameter σsurface charge density λlinear charge density Elfield near a line Epfield between plates πpi ε₀permittivity of free space A=π⋅r2 Φ=E⋅A Φ=qε0 A=π⋅D2 q=σ⋅A El=λ2⋅π⋅ε0⋅r Ep=σε0
Bmagnetic field Nturns Aarea νfrequency ε₀peak emf πpi ε0=N⋅B⋅A⋅2⋅π⋅ν Nturns Aarea Rresistance Bmagnetic field θangle to the field Φmagnetic flux εinduced emf Iinduced current Δttime taken flux through a loop emf from the change of flux current driven by the emf Bmagnetic field Rlength of the rod ωangular speed εinduced emf ε=B⋅ω⋅R22
Eelectric field Bmagnetic field kwave number ωangular frequency λwavelength νfrequency cspeed of light πpi E=c⋅B k=2⋅πλ ω=2⋅π⋅ν c=ν⋅λ
Ccapacitance Qcharge Vvoltage Uenergy stored Aarea dplate separation Kdielectric constant ε₀permittivity of free space Q=C⋅V C=K⋅ε0⋅Ad U=C⋅V22 Efield strength pdipole moment θangle to the field Upotential energy Qheat given out qcharge llength of the dipole τtorque energy of a dipole in a field p=q⋅l τ=p⋅E⋅sin⁡θ energy lost as heat qcharge rdistance Vpotential Wwork to bring in kcoulomb constant V=k⋅qr W=q⋅V qcharge rdistance Upotential energy kcoulomb constant U=k⋅q1⋅q2r
Mcentral mass Rccentral radius hheight of the orbit kKkeplers constant Ebbinding energy vspeed Ggravitational constant rradius πpi Tperiod mmass v2=G⋅Mr kK=4⋅π2G⋅M T2=kK⋅r3 r=Rc+h Eb=G⋅M⋅m2⋅r rdistance from the centre hheight above the surface Vggravitational potential veescape speed vspeed Rradius of the body mmass height is measured from the surface potential of a mass escape speed from where it is energy kept in free flight mmass Rradius of the body gssurface gravity rgseparation Eggravitational intensity Ggravitational constant gs=G⋅mR2 Eg=G⋅mrg2
Ppressure Vvolume namount Ttemperature Mmolar mass ρdensity Rgas constant P⋅V=n⋅R⋅T ρ=n⋅MV lmean free path νccollision frequency Rgas constant Ttemperature πpi dmolecular diameter Ppressure NAavogadro constant vrmsrms speed l=R⋅T2⋅π⋅d2⋅P⋅NA νc=vrmsl dmolecular diameter rmolecular radius Vmvolume of the molecules fVfraction filled by molecules Nmolecules πpi Vvolume namount d=2⋅r Vm=N⋅π⋅d36 fV=VmV n≠0 mmass Nmolecules namount Mmolar mass NAavogadro constant m=n⋅M N=n⋅NA vrmsrms speed Eavgaverage thermal energy Rgas constant Ttemperature Mmolar mass NAavogadro constant vrms=(3⋅R⋅TM)0.5 Eavg=3⋅R⋅T2⋅NA fdegrees of freedom Cvmolar heat at fixed volume ΔTtemperature rise Qheat at fixed volume Rgas constant namount Cv=f⋅R2 Q=n⋅Cv⋅ΔT
pmomentum Jimpulse p₀starting momentum pfinal momentum mmass v₀starting velocity vfinal velocity Fnetnet force Δttime taken p→0=m⋅v→0 p→=m⋅v→ J→=p→-p→0 J→=F→net⋅Δt mmass Fnetnet force Fforce Wweight aacceleration ggravity F→net=m⋅a→ m≠0 free of forces weight of a body net force is the resultant second law in size
μrrelative permeability Icurrent nturns per length Hmagnetic intensity Mmagnetisation Bmagnetic field Immagnetising current μ₀permeability of free space H=n⋅I M=(μr-1)⋅H B=μr⋅μ0⋅H B=μ0⋅n⋅(I+Im)
dpiston diameter rpiston radius sstroke Vvolume pushed Aarea πpi d=2⋅r A=π⋅d24 V=A⋅s mmass ggravity Fthrust Aarea Ppressure P=FA Papressure at the surface ρdensity hdepth Pggauge pressure ggravity Ppressure Pg=ρ⋅g⋅h P=Pa+Pg ggravity aradius ρdensity σdensity of the fluid vtterminal velocity ηcoefficient of viscosity vt=2⋅a2⋅(ρ-σ)⋅g9⋅η Ssurface tension rradius ΔPexcess pressure ΔPsexcess pressure in a soap bubble Pipressure inside lslider length FSpull of the film Ppressure ΔP=2⋅Sr ΔP_s=4⋅Sr Pi=P+ΔP FS=2⋅S⋅l mmass ggravity Aarea lfilm thickness vspeed Fviscous drag ηcoefficient of viscosity F=η⋅A⋅vl
Bbulk modulus ΔVVfractional compression aedge Vvolume ΔVfall in volume ρBdensity when squeezed Pggauge pressure ρdensity B=PgΔV_V V=a3 ΔV_V=ΔVV ρB=ρ1-ΔV_V mmass ggravity Fshearing force Aface lfaceface length wfaceface width Lheight Δxshift σsshearing stress θsshearing strain Gshear modulus A=lface⋅wface σs=FA θs=ΔxL G=σsθs mmass ggravity Fload rthickness Ddiameter Across section Loriginal length ΔLextension σstress εstrain Yyoungs modulus πpi r=D2 A=π⋅r2 σ=FA ε=ΔLL Y=σε
αdirection vvelocity vx=v⋅cos⁡θ ggravity aacceleration ax=0 rradius vspeed ωangular speed nrevrevolutions νfrequency accentripetal acceleration qagainst gravity Tperiod ggravity mmass Fccentripetal force πpi Δttime taken v=ω⋅r ω=2⋅πT ν=1T ν=nrevΔt ac=v2r q=acg Fc=m⋅ac volumevolume massmass speedspeed densitydensity nnumber of moles angularfrequencyangular frequency workwork currentcurrent temperaturetemperature pressurepressure timetime powerpower stotal path length energyenergy gravitationalpotentialgravitational potential μcoefficient of friction chargecharge accelerationacceleration velocityvelocity displacementdisplacement angularvelocityangular velocity forceforce angularmomentumangular momentum plinlinear momentum electricfieldelectric field averagevelocityaverage velocity magneticmomentmagnetic moment vABrelative velocity impulseimpulse Afirst vector Bsecond vector φangle between Rresultant βresultant direction αdirection Axx component Ayy component R2=A2+B2+2⋅A⋅B⋅cos⁡φ R⋅sin⁡β=B⋅sin⁡φ R⋅cos⁡β=A+B⋅cos⁡φ Ax=A⋅cos⁡α Ay=A⋅sin⁡α A=Ax2+Ay2
vvelocity Δvchange of velocity aavaverage acceleration v₀starting velocity vfinal velocity Δttime taken Δ→v=v→-v→0 a→av=Δ→vΔt vvelocity v1=v2-v3 aacceleration ggravity ttime vfinal velocity v₀starting velocity xfinal position x₀starting position v→=v→0+a→⋅t x→=x→0+v→0⋅t+a→⋅t22 v→2=v→02+2⋅a→⋅(x→-x→0) x→-x→0=(v→+v→0)⋅t2 a1=a2 xposition Δxdisplacement dpath length Δttime taken vavaverage velocity cavaverage speed x₀starting position xfinal position Δ→x=x→-x→0 v→av=Δ→xΔt cav=dΔt d1=d2+d3 Δt1=Δt2+Δt3
Bmagnetic field Icurrent Nturns Rradius Aarea mmagnetic moment θangle to the field τtorque πpi m=N⋅I⋅π⋅R2 m=N⋅I⋅A τ=m⋅B⋅sin⁡θ Icurrent Nturns Rradius Llength of the coil nturns per length Bcfield at the centre Bsfield inside ddistance from the wire Bwfield near a wire μ₀permeability of free space πpi Bc=μ0⋅N⋅I2⋅R n=NL Bw=μ0⋅I2⋅π⋅d Bs=μ0⋅n⋅I ggravity Bmagnetic field mmass qcharge vspeed Icurrent llength in the field Fforce on a wire fforce per length rradius of the path θangle to the field νfrequency of revolution πpi F=I⋅l⋅B f=I⋅B⋅sin⁡θ r=m⋅vq⋅B v=2⋅π⋅r⋅ν
mHhydrogen atom mass mnneutron mass mmass Eenergy Zatomic number Amass number dmmass defect Ebbinding energy Qq value cspeed of light E=m⋅c2 dm=Z⋅mH+(A-Z)⋅mn-m Eb=dm⋅c2 Q=dm⋅c2 R₀size of a nucleon s share Amass number Zatomic number mmass Rnuclear radius ρnuclear density Ubcoulomb barrier πpi kcoulomb constant eelementary charge R=R0⋅A0.333333333 ρ=m4⋅π⋅R33 Ub=k⋅(Z⋅e)22⋅R
Nrepetitions νfrequency Tperiod Δttime taken ν=NΔt T=1ν Aamplitude sstroke ωangular frequency νfrequency φphase constant vmaxmaximum speed amaxmaximum acceleration aacceleration πpi xposition Δttime taken vvelocity s=2⋅A ω=2⋅π⋅ν vmax=ω⋅A amax=ω2⋅A displacement in shm velocity in shm acceleration in shm amplitude from where and how fast gsurface gravity Llength of the string Tperiod πpi T=2⋅π⋅Lg mmass kspring constant Kkinetic energy Upotential energy Etotal energy ωangular frequency Aamplitude vvelocity xposition ω2=km E=k⋅A22 energies at an instant
rsreflectance s polarised rpreflectance p polarised rreflectance τtransmittance μ₁refractive index of first medium iangle of incidence μ₂refractive index of second medium rrangle of refraction rs=(μ1⋅cos⁡i-μ2⋅cos⁡rrμ1⋅cos⁡i+μ2⋅cos⁡rr)2 rp=(μ1⋅cos⁡rr-μ2⋅cos⁡iμ1⋅cos⁡rr+μ2⋅cos⁡i)2 r=rs+rp2 r+τ=1 rlangle of reflection iangle of incidence i=rl μrefractive index rrangle of refraction μ₁refractive index of first medium μ₂refractive index of second medium ccritical angle iangle of incidence μ1⋅sin⁡i=μ2⋅sin⁡rr μ1⋅sin⁡c=μ2⋅sin⁡90° rr=90° i>c rr<i rr>i n₁index before n₂index after Rradius of curvature uobject distance dodistance in front vimage distance u=−do n2v-n1u=n2-n1R μ₂₁relative refractive index μ₂refractive index of second medium μ₁refractive index of first medium μ21=μ2μ1 Rradius of curvature rsizesize of the radius dodistance in front ffocal length fsizesize of the focal length uobject distance vimage distance mmagnification hoobject height hiimage height u=−do f=R2 1v+1u=1f m=−vu m=hiho nrefractive index of the lens nsindex of the surroundings R₁first radius R₂second radius r₂size of the second radius ffocal length fsizesize of the focal length Ppower of the lens dodistance in front uobject distance vimage distance mmagnification hoobject height hiimage height u=−do 1f=(nns-1)⋅(1R1-1R2) P=1f 1v-1u=1f m=vu m=hiho rreflectance r=1
niintrinsic carriers naatoms xddoping NDdonors neelectrons nhholes ND=xd⋅na ne=ND ne⋅nh=ni2
Mmass Rradius Imoment of inertia Fpull τtorque lcord unwound Krotrotational kinetic energy Langular momentum αrangular acceleration θangle turned ωangular velocity I=M⋅R22 τ=I⋅αr l=R⋅θ torque of a pull at the rim kinetic energy of turning angular momentum of turning ωangular velocity αrangular acceleration θangle turned nrevturns ω₀starting angular velocity ωfinal angular velocity Δttime taken πpi ω=ω0+αr⋅Δt θ=ω0⋅Δt+αr⋅Δt22 ω2=ω02+2⋅αr⋅θ nrev=θ2⋅π
mmass sspecific heat capacity Llatent heat T₁temperature at first T₂temperature after Qheat to warm QLheat to change phase Qinheat taken in Q=m⋅s⋅(T2-T1) QL=m⋅L Qin=Q+QL Kthermal conductivity Across section Llength of the rod TChot end TDcold end Hheat current H=K⋅A⋅(TC-TD)L Ttemperature kccooling constant T₀starting temperature Tffinal temperature Δttime taken T1-T2Δt=−kc⋅(T2+T12-T3) L₁length at first L₂length after Δlchange in length T₁temperature at first T₂temperature after αlcoefficient of linear expansion L2-L1=αl⋅L1⋅(T2-T1) Δl=L2-L1
Ppressure Vvolume γratio of specific heats P₁starting pressure P₂final pressure V₁starting volume V₂final volume P1⋅V1γ=P2⋅V2γ ΔQheat absorbed ΔWwork done by the system Wonwork done on the system ΔUchange of internal energy ΔQ=ΔU+ΔW Won=−ΔW
llength ggravity mmass Tperiod kconstant xpower of length ypower of gravity zpower of mass vspeed hheight ttime aacceleration s₀start v₀starting speed sdistance m₀rest mass Kkinetic energy T=k⋅lx⋅gy⋅mz x+y=0 -2⋅y=1 z=0 m⋅v22=m⋅g⋅h s=s0+v0⋅t+a⋅t22 Vvolume vspeed aacceleration Fforce ρdensity Wwork Ssurface area hheight bbreadth Sccylinder surface area Vsvolume of a slab ρrelrelative density ρwdensity of water mllinear magnification liimage length loobject length Aiimage area Aoobject area VNvolume of them all Vmmolar volume RVroom to spare llength ttime mmass πpi rradius Aarea Nnumber of entities V=l3 v=lt a=vt F=m⋅a ρ=mV W=F⋅l S=6⋅l2 V=4⋅π⋅r33 Sc=2⋅π⋅r⋅(r+h) A=l⋅b Vs=l⋅b⋅h ρrel=ρρw ml=lilo ml2=AiAo VN=N⋅V RV=VmVN πpi cspeed of light hplancks constant eelementary charge Ggravitational constant kcoulomb constant ε₀permittivity of free space μ₀permeability of free space Rgas constant NAavogadro constant afirst measured Δaerror in first δarelative error in first bsecond measured Δberror in second δbrelative error in second pproduct Δperror in product δprelative error in product ttotal ddifference lcleast count dmscale division Nddivisions read past δa=Δaa δb=Δbb p=a⋅b δp=δa+δb Δp=δp⋅p t=a+b d=a-b lc=dmNd llength mmass ttime Ielectric current Ttemperature namount of substance Ivluminous intensity sarc length rradius θplane angle Aarea Ωsolid angle tlightlight time dlightlight distance Nnumber of entities Bbaseline Ddistance away θpparallax angle cspeed of light NAavogadro constant θ=sr Ω=Ar2 dlight=c⋅tlight N=n⋅NA θp=BD
θangle to the light s polarisation tshare passed t=cos⁡θ2
νfrequency νbeatbeat frequency νbeat=ν1-ν2 vspeed of sound Llength of the pipe nharmonic νfrequency ν=n⋅v4⋅L Ppressure Ttemperature Mmolar mass ρdensity γratio of specific heats vspeed of sound Rgas constant ρ=P⋅MR⋅T v=γ⋅Pρ vspeed of sound Llength of the pipe nharmonic νfrequency ν=n⋅v2⋅L aamplitude kwave number ωangular frequency λwavelength Tperiod νfrequency vwave speed Δxseparation Δφphase difference πpi k=2⋅πλ ω=2⋅πT ν=1T v=ν⋅λ Δφ=k⋅Δx mmass Llength of the string μlinear mass density Ttension vwave speed ttravel time nharmonic νfrequency kwave number ωangular frequency μ=mL v=Tμ v=ωk t=Lv ν=n⋅v2⋅L
Kkinetic energy ΔKchange of kinetic energy mmass vvelocity Fnetnet force Fforce Wweight WFwork Wgwork by gravity kinetic energy of a body kinetic energy gained work energy theorem Ppower Fnetnet force Fforce Wweight vvelocity power of a force WFwork Wgwork by gravity Wnetnet work Fnetnet force Fforce Wweight Δxdisplacement work of a steady force work of the net force work of the weight