PHY 2049: Physics IISlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14PHY 2049: Physics IITutoring Center is open in room NPB 1215, M-F 12:00AM -4:00PM. It is free.Hopefully all Wiley Plus problems have beensolved. Please see me immediately after the class if there is still an issue.PHY 2049: Physics IIAbout bicycle riding: If some one shows you a trick, it means that,It is possible to do that trickThe person who showed you, can do the trick. It does not mean that you can do the trick.Try it a lot of times and you can too.Electric fields from different geometrical objects.wiresRings and disksPlanesAnother algorithm Al-Khwarizmi the Persian astronomer and mathematician, wrote a treatise in Arabic in 825 AD, On Calculation with Hindu Numerals, which was translated into Latin in the 12th century as Algoritmi de numero Indorum[1], which title was likely intended to mean "Algoritmi on the numbers of the Indians", where "Algoritmi" was the translator's rendition of the author's name; but people misunderstanding the title treated Algoritmi as a Latin plural and this led to the word "algorithm" (Latin algorithmus) coming to mean "calculation method". The intrusive "h" is most likely due to a false cognate with Greek αριθμος arithmos = "number". (wikipedia: http://en.wikipedia.org/wiki/Algorithm#EtymologyPHY 2049: Physics IIFlux and Gauss’ theoremPHY 2049: Physics IIGaussian (imaginary) surfacesFlux = Φ = ∑ E.dAE.dA for a cube is easy to visualize.Let calculus do it for a sphere or any other shape.Φc = qtotal /εoS1: Φc = q/ εoS2: Φc = -q/ εoS3: Φc = 0S4: Φc = 0•For a cylinder with axial field, no contribution to flux from the side walls.•From the far top, >0•Near (bottom) , <0PHY 2049: Physics IINo force/field from the charge outsideOn inside circle E.4πr2=q/εo Coulomb’s lawVery outside, E = k 5q/r2P++++++PHY 2049: Physics IIThe electric field in a metal is zeroCharge +q on inside surface.Because it is neutral, outside surface must be -q.PHY 2049: Physics IIElectric field is radial.E.A = 0 for the top and bottom surfaces.Sideways:E 2πrh = λh/ε0E = λ/ 2πrε0PHY 2049: Physics IIPlane2EA = σA/εoE = σ/2εoPHY 2049: Physics IIE = σ/εo insidePHY 2049: Physics IIGauss’ theoremElectric fields due to a point charge (Coulomb’s), a wire and a plane.Charge shells don’t act inside.In an insulator with uniformly distributed charge, only charge enclosed contributes to the
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