Parallel plate Definition and 275 Threads

  1. B

    Why Is There a Negative Sign in the Modal Impedance of TEn Mode?

    Hi, I'm working on a parallel plate wave guide for wave propagation and had a question about it. Here's a quick diagram: While analyzing an EM field polarized in the y-direction, the modal impedance of the TEn mode comes out to be: Why is that negative sign there? If someone could just...
  2. Drakkith

    Increase in Charge on a Parallel Plate Capacitor

    Homework Statement The charge on the 3.00 cm2 area plates of an air-filled parallel plate capacitor is such that the electric field is at the breakdown value. By what factor will the maximum charge on the plates increase when bakelite is inserted between the plates? (The dielectric strength of...
  3. E

    Grounding parallel plate conductors

    Homework Statement So, I always make mistakes on problems such as this (the grounding part), so I'm hoping someone could really explain to me how the process works instead of just answering this particular problem. There are n large parallel plate conductors carrying charges Q1, Q2,... Qn...
  4. A

    Understanding the Effects of a Conducting Plate on a Parallel Plate Capacitor

    Homework Statement Consider a parallel plate capacitor of area A and separation d. The plates are isloated. One has charge +Q and the other -Q. An isolated conducting plate of area A and thickness t is inserted between the plates as shown. a. Find the E fields between the conductors b. Find...
  5. D

    Understanding Charge Accumulation in Parallel Plate Capacitors

    Homework Statement My lecture notes say that no current flows through capacitors as the dielectric material is a poor conductor. It goes on to say that the capacitor appears as an open circuit to a DC voltage source. It then says that charge will accumulate on the plates with an equal amount of...
  6. Rath123

    Is the Time Constant Affected by Changing Plate Distance in an RC Circuit?

    If, by some means, the distance between the parallel plates of the capacitor is reduced to half of what it was before, would the time constant change? If yes, then what would be the new time constant?
  7. P

    Dielectric inserted in parallel plate capacitor

    Homework Statement When a dielectric is partially inserted between two plates of a capacitor that is disconnected, what will be it's motion? Also what will be its motion if the capacitor is connected to a battery? Homework EquationsThe Attempt at a Solution For the first part. I think the...
  8. S

    Resistance and Capacitance of Two Metal Plates "Touching"

    Homework Statement Two conductive metal plates are bonded together. Upon bonding, an oxide layer forms between them. The oxide layer is negligible thus the overall resistance of the plates is small. However I am having trouble finding this overall resistance, i.e., trying to find Cp and Rp...
  9. roms05

    Parallel Plate Capacitor with variable Dielectric (water)

    Hi everyone. I have a problem with my device. It consists of a parallel plate capacitor with plates made of galvanized iron. Each plate's area is 1mx1inch. It's connected to a bleeder resistor and basically, the circuit is just a simple RC circuit. The source I'm using is a constant 5V DC...
  10. S

    Potential in parallel plate system from charge density?

    Homework Statement Note - I have used an image here. For the simple reason I don't want to confuse anyone by missing out subscripts. But if that is not acceptable let me know and I will attempt to write it out. Homework Equations I have considered using Poissons equation - but couldn't...
  11. S

    Path of Light Beam in Plane Parallel Plate

    Homework Statement In plane parallel plate the refractive index is a function of coordinate ##z##, so that ##n=n_0 -{n}'z^2## for ##{n}'>0##. The origin of the coordinate system is in the middle of the layer, and ##z## is parallel to the normal of the layer. In paraxial approximation calculate...
  12. B

    Removing The Dielectric From A Parallel Plate Capacitor

    Homework Statement Consider a parallel-plate capacitor, with two square plates of side \mathrm{12.0 cm} separated by a \mathrm{4.50- mm} gap. Half of the space between the gaps is filled with a material of dielectric constant \mathrm{K = 3.40}, while the rest is filled with just air. (a) What...
  13. roms05

    Low Cost Parallel Plate Capacitor

    Hello! I'm hoping someone can help me with my problem. I'm currently working on a low cost parallel plate capacitor. I used a galvanized iron as the plate material since this is a low cost material. The problem is when I measure the voltage across the capacitor, the voltage read peaks at a...
  14. X

    Energy stored in parallel plate capacitor

    Can anyone please tell me whether I have solved this question correctly or not. 1. Homework Statement A parallel plate capacitor has a charge of 0.040µC on each plate with a potential difference of 240 V. The parallel plates are separated by 0.20 mm of air. What energy is stored in this...
  15. K

    Inf. Parallel Plate Capacitors and Potential Energy

    Hopefully no one minds that I post a couple questions in a row as long as I'm following the rules: 1. Homework Statement Two infinite parallel plates labelled W and X are separated by 5.2 cm. The electric potential between the plates is 150 V. An electron starts from rest at time tW and...
  16. S

    Impact speed of an electron in a parallel plate capacitor

    Homework Statement The electric field strength is 2.50×104 N/C inside a parallel-plate capacitor with a 1.20 mm spacing. An electron is released from rest at the negative plate. What is the electron's speed when it reaches the positive plate? Homework Equations F = eE = ma vf2 = vi2 + 2ad...
  17. N

    Capacitance of an asymmetrical parallel plate capacitor

    I've been looking all over and to my great surprise have not be able to find an answer to this question. What is the capacitance between to parallel plates if one plate is larger than the other? For example, the capacitance between a 1" diameter plate and a 4" diameter plate. Thanks.
  18. K

    Inserting metal to parallel plate capacitor

    If there is a parallel plate capacitor with plate area, A, plate separation, d, and a slab of copper of thickness, b, is inserted exactly halfway between the plates. How to find it's new capacitance, C', and new potential difference, V' ? Answer: V' = E(d-b) and C' = εA / (d-b) I...
  19. D

    Dimensions of Parallel Plate Capacitors

    Homework Statement The electric field between two circular plates of a capacitor is changing at a rate of 1.5 x 10^6 V/m per second. If the displacement current at this instant is Id = 0.80 x 10^-8A, find the dimensions of the plate. Homework Equations Id = ΔQ/Δt = ε0(ΔΦE/Δt) ΦE = EA Q = CV...
  20. AdityaDev

    Doubt in parallel plate capacitor

    I was going through the capacitor lesson in my textbook. In it its written "...both positive and negative plates will produce electric field in the same direction, hence the electric field adds up...outside the plates, electric field is zero since the field due to negative and positive charges...
  21. H

    Why is Electric Field Constant between a Parallel Plate Capacitor?

    So electric field tells us the force per unit charge that is felt by a test charge at a distance d from a source charge. So it tells us that the closer the test, or other charge, is to the source charge ,the stronger the interaction, and also that the larger the source charge, the stronger the...
  22. Y

    Using Method of Imaging for two point charges between Parallel Plate Capacitors

    Homework Statement Use either image charge method of separation of variables to solve: The distance between two large, grounded parallel conducting plates is 4x. Between them, two point charges +Q and -Q are inserted and have a distance x and 3x from one of the plates. (A line connecting the...
  23. S

    Calculate Potential Energy of Electron at a Parallel Plate Capacitor

    Homework Statement An electron with a speed of 5.0x10^6 m/s is injected into a parallel plate apparatus, in a vacuum, through a hole in the positive plate. The electron collides with the negative plate at 1.0x10^6 m/s. What is the potential difference between the plates? Vi= 5.0x10^6...
  24. A

    Electric charge in parallel plate capacitor with 2 parallel dielectrics

    Homework Statement My question is: If we have a parallel plate capacitor with 2 parallel dielectrics both taking A/2 of the complete surface, is the total electric charge equal to sum of the electrical charges in the first dielectric and the second dielectric, i.e is qtotal=q1+q2=σ1*A/2+σ2*A/2...
  25. J

    Parallel plate conductors of opposing charge and unequal magnitude

    A question has occurred to me during preparation for a Physics exam. My textbook does a good job of discussing a capacitor charged equal but opposite. But I want to take it a step further. My question is how to calculate the E field between 2 plates of opposing charge that have unequal...
  26. C

    Parallel plate capacitor problem

    Homework Statement A parallel plate capacitor is constructed with plates of area .0280 m^2 and separation .550mm Find the charge on each plate when potential difference between plates is 20.1V. what separation would be necessary to give a charge of 20 nC on each plate?Homework Equations Im...
  27. ShayanJ

    Parallel plate capacitor with layers of dielectrics in between

    Consider a parallel plate capacitor with layers of dielectric between its plates somehow that the interfaces between them are parallel to the plates of the capacitor. If the surface charge density on the plates of the capacitors be \sigma , gauss's law gives D=\sigma which is the same inside...
  28. G

    Polarized Slab between Parallel Plate Electrode

    Homework Statement Find the electric field everywhere for the following permanently polarized structures which do not support any free charge: (b) Permanently polarized slab P_0 i_x of thickness b placed between parallel plate electrodes in free space at potential difference V_0...
  29. kartikwat

    Can a capacitor still function without both plates?

    What would have been if the opposite and equal charge wouldn't have been induce on 2nd conductor in parallel plate capacitor when connected to a battery
  30. tristanm

    Parallel Plate Capacitor and Battery

    Homework Statement Two parallel plates, each having area A = 3558 cm2 are connected to the terminals of a battery of voltage Vb = 6 V as shown. The plates are separated by a distance d = 0.54 cm. 1) What is Q the charge on the top plate? 3.5*10^-9 C 2) What is U, the energy stored in...
  31. R

    Electric Field of a Not So Parallel Plate Capacitor

    Does anyone have any idea how I could begin to examine the field of two conducting plates which are side by side instead of parallel ?
  32. T

    How do I calculate the acceleration of a particle in a parallel plate capacitor?

    Homework Statement The Attempt at a Solution All I need to know is the acceleration acting on the particle after the potential is applied. v_f^2 = v_i^2 + 2ad (1*10^{-5})^2 = -(1*10^{-5})^2 + 2a(1*10^{-3}) a = 1*10^{-7} m/s2 Is this the correct approach to finding acceleration?
  33. A

    Work required to separate parallel plate capacitors

    Homework Statement A parallel plate capacitor with capacitance C is charged to a value q and then isolated. The separation between the plates is then tripled. What was the work required to separate the capacitors?Homework Equations U=1/2CV^2 Q=CV C=ε0A/dThe Attempt at a Solution...
  34. T

    Electrostatics - 3rd plate inserted into parallel plate capacitor

    Electrostatics -- 3rd plate inserted into parallel plate capacitor Homework Statement This question is from the book by I.S Grant and W.R Phillips on Electromagnetism. Two large parallel plates of area A and distance d apart are maintained at potentials 0 and V. A third similar plate...
  35. L

    Calculating Electron Trajectory in a Parallel Plate Conductor

    Homework Statement An electron is fired at a speed vo = 5.6 ✕ 10^6 m/s and at an angle θo = -40° between two parallel conducting plates that are D = 2.5 mm apart, as in Figure P16.66. The voltage difference between the plates is ΔV = 103 V. Homework Equations F = Eq E = V/d a = F/m The...
  36. T

    Parallel Plate Capacitor Diameter

    Homework Statement Two circular disks spaced 0.50 mm apart form a parallel-plate capacitor. Transferring 1.70 ×109 electrons from one disk to the other causes the electric field strength to be 3.50 ×105N/C. What are the diameters of the disks? Homework Equations Refer to attachment...
  37. E

    Electron launched at an angle in a parallel plate field.

    Homework Statement http://puu.sh/6i6HY.png Homework Equations Fe = q*Ee The Attempt at a Solution a) dx = vx*t 0.0682 = 4.92*106 * cos(68) * t t = 0.0682 / [4.92*106 * cos(68)] = 3.70036*10-8 seconds dy = dyi + vy*t + at2 0 = 0 + 4.92*106 * [0.0682 / [4.92*106 * cos(68)]] * sin(68) + a...
  38. U

    Dielectric half-filled parallel plate capacitor

    Question taken from Griffiths Pg 185, Problem 4.19: For part (b): -Why are the electric fields the same whether in dielectric or in air? In part (a), they are clearly different! -Why is σ_{tot} = ε_{0}E = ε_{0}\frac{V}{d} -In calculation of capacitance, why is the total charge (\frac...
  39. T

    Breakdown in parallel plate capacitor with dielectric

    Homework Statement Two related questions (from Electromagnetics by Notaros) The dielectric of a parallel-plate capacitor has two homogeneous parts, referred to as dielectric 1 and dielectric 2. The boundary surface between the parts is flat and parallel to the capacitor plates. The dielectric...
  40. T

    Energy of a parallel plate capacitor homework

    Hi all "A parallel plate capacitor in which plates of area A are separated by a distance d, has a capacitance C = \frac{Aε_{0}ε_{r}}{d} It is charged to a pd V. Neglecting edge effects, derive an equation for the electric field E in the capacitor, and show that the energy stored per unit volume...
  41. mrspeedybob

    Multiple parallel plate capacitor question.

    Consider a capacitor with 4 parallel plates and 3 dielectric insulators arranged like this...+I-I+I- The insulator in the center has an equal amount of + and - charge on each side of it so shouldn't the electric field across this insulator be almost zero? If I constructed this capacitor with...
  42. F

    Parallel Plate Waveguide Loss Dependence On Mode

    Hi, The attenuation resulting from puting a signal into a parallel plate waveguide is dependent on the excited mode. Why does the TM mode have greater attenuation than the TE mode? I can see in the maths it 'works out' to be that, but what would be a more conceptual/physical reason? Is the...
  43. A

    Energy radiated by a parallel plate capacitor

    Homework Statement A parallel-plate capacitor C , with plate separation d , is given an initial charge ±Q_{0}. It is then connected to a resistor R, and discharges, Q(t)=Q_{0} e^{-t/RC} 2 (a) What fraction of its energy Q_{0}^{2}/2C does it radiate away? Homework Equations The equations for...
  44. F

    Parallel Plate Waveguide Basic Functionality Issue

    Hi, I think I'm missing something with how a parallel plate waveguide works. In the picture I've shown below, there intensity of the E-field change depending on how far across the waveguide it is. While I know that this has to happen in order for anything to propagate, I don't quite...
  45. O

    Final Velocity in parallel plate capicator?

    1. The plates of a parallel plate capacitor are separated by a distance (4cm). A point charge of magnitude (q=2e) (3.2*10^-19 C) is fired horizontally through a small hole in the positive plate of the capacitor. The charge is fired with speed (8.5 *10^5 m/s) and, upon reaching point M (located @...
  46. H

    Green's Function and Parallel Plate Waveguide

    Homework Statement A parallel plate waveguide has perfectly conducting plates at y = 0 and y = b for 0 ≤ x < ∞ and -∞ < z < ∞. Inside that bound, the waveguide is filled with a dielectric with k as a propagation constant. The Green's function to be satisfied is \nabla^2G + k^2G =...
  47. V

    Capacitance of two parallel plate capacitors

    Homework Statement Two square metal plates with sides of length 0.1 m are separated in vacuum by 10-3 m. Find their capacitance. Homework Equations C = Q/V For a parallel plate capacitor: C = E0A/L The Attempt at a Solution If A is supposed to be the length of the metal...
  48. A

    Parallel Plate Capacitor with Dialectric

    Homework Statement How much charge can be placed on a capacitor with air between the plates before it breaks down if the area of the plates is 5 cm^2. Homework Equations C=\frac{Q}{\Delta V} C=kC_o C=k\frac{\varepsilon _o A}{d} Where "k" is the dialectric constant. The Attempt at a...
  49. S

    Capacitance approximation of a non parallel plate capacitor

    I am in process of designing a homemade capacitance sensor and I'd like to have an approximation of the resulting capacitance of the following geometry. The plates are placed on the outer surface of a food grade plastic cylinder. The distance z between their edges is many times smaller than the...
  50. T

    Conducting slab between the plates of parallel plate capacitor

    Homework Statement The space between the plates of a parallel plate capacitor is completely filled with a conducting slab.What is the capacitance of the system ? Homework Equations The Attempt at a Solution The capacitance of a capacitor when a dielectric medium is placed...
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