Plates Definition and 622 Threads

  1. M

    Calculation of large deflection of plates

    I want to calculate/preparing a spread sheet for large deflection of simple supported plates. I search for too many documents but all of them for small deflection d≤ t\2 (d deflection, t thickness of sheet). I found a website http://www.xcalcs.com/cgi-bin/tutti/x3calcs.cgi?d=i_4_2_1_0_0&l=en but...
  2. P

    Attraction of metal plates and ball

    Homework Statement I'm having trouble understanding charges on Earthed plates I think. I know the answer for this question is that the ball will be attracted to the high voltage plate and stay there but I do not know why is that. Homework Equations A light metal ball is suspended between...
  3. T

    Is there a lower limit to the separation between capacitor plates?

    Let's say I build a parallel plate capacitor using two metal plates with perfectly smooth surfaces. They are separated by some small distance d, with only vacuum between them. I then apply some AC voltage across the plates. Is there some effect which causes loss in the capacitor (equivalent...
  4. Z

    Photon polarization and 1/2 wave plates

    I have seen this explained but would appreciate comments as to whether I understand it correctly. #1. A vertically polarized photon hits a 1/2 wave plate set at 90 degrees will not pass through since cos(90)^2 = 0 #2. 50% of vertically polarized photons that hit a 1/2 wave plate set at...
  5. H

    Why Do Glass Plates with Water Not Separate Under Weight but Slide Easily?

    1. I took two glass plates with a thin film of water trapped in it. One of plates had hook in it. Weights were hung in it. I found that these plates didn't separate until weights of about 2-3 kg was applied. 2.But if slided, it moved easily. I can explain observation no. 2. It is because the...
  6. S

    Constructive/Destructive Interference of Two Glass Plates

    Homework Statement "Light is incident from above two plates of glass separated on both ends by small wires of diameter d = .6um. Considering only interference between light reflected from the bottom surface of the upper plate and light reflected from the upper surface of the lower plate...
  7. W

    3D Electric field vector calculation for two parallel plates

    Homework Statement For two metal plates parallel to each other, when voltages was applied to them, there is an electric field in between. I measured the voltage at 12 points (known x,y,z) between them. these 12 points formed a rectangular box (three on each of four lines, which is...
  8. R

    Finding Electric Force between 2 parallel plates

    Homework Statement An alpha particle is placed between two horizontal parallel charged plates that are 2.00 cm apart. The potential difference between the plates is 12.0 V. WHAT is the ELECTRIC FORCE acting on the alpha particle? -Mass of alpha particle: 6.65 x 10^-27 kg Homework...
  9. C

    Gauss' Law for finding E between metal plates

    I'm having some difficulty applying Gauss's Law to metal plates. From what I've studied it seems to me that Gauss's Law only really works when there is spherical symmetry, in all other cases it is an approximation. Am I correct in inferring this? However, in a case where the distance between...
  10. R

    How to find the electric field between two ideal plates?

    There are two plates that lie horizontally parallel to each other, separated by a distance of 1 cm. Each plate is 2 cm long. The question wants you to assume that the electric field between the two fields is constant, and pointing directly downwards. On the left-most edge of this plate...
  11. B

    Separating capacitor plates: (+) or (-) work?

    Homework Statement Consider a parallel-plate capacitor with plates of area A and with separation d. Find F(V), the magnitude of the force each plate experiences due to the other plate as a function of V, the potential drop across the capacitor. Hint i used If the plate separation were changed...
  12. robphippen

    Understanding the Use of Quarter-Wave Plates for 3D Cinema

    So... 3d cinema relies on circular polarized light these days. Creating circular polarized light requires the use of a quarter-wave plate, which exploits birefringence to; (a) effectively create two rays of light linearly polarized at right angles (b) retards one of them by a quarter...
  13. N

    Thin ceramic plates sources / manufacture techniques?

    I need to insulate the area between two heat sinks. The gap is about 10mm, and the bottoms of the heat sinks are facing each other with a peltier chip sandwiched in-between. However the two sinks are in separate enclosed sections, and I need to insulate the hot side from the cold side as much as...
  14. P

    Force between the plates of a plane capacitor

    I found this problem while self-studying Electricity and Magnetism, and I want to know if my solution is rigorous. Homework Statement Show that the plates of a plane capacitor attract each other mutually with a force equal to F=\frac{q^2}{2\epsilon_0 A} Obtain this result by calculating the...
  15. F

    Combining Quarter-Wave Plates: Effects & Differences

    If we put two identical quarter-wave plates together what will be the resulting plate? How would it be different from one of the quarter-wave plates?
  16. N

    Magnetic field of parallel plates

    Apologies if this has been answered before. I did search but couldn't find it... Imagine two fixed conducting parallel plates separated by 10cm of air. If an alternating voltage is applied to these at 10MHz an electric field produced between the two plates like a giant capacitor. Given that...
  17. D

    Vena contracta in orifice plates

    Hi, does anybody know how to find the diameter of the vena contracta in gas/vapour flows in orifice plates?
  18. C

    Plate Bending Analysis: Point Load Distribution

    Hello. First time on the forum. I have a plate being supported off a series of beams (see pdf). The beams are close together and restrained. The plate is simply supported on all sides and the beams simply supported. The plate is to be used to distribute a point-load over the beams and is...
  19. S

    How Does a Thin Plate Between Infinite Plates Affect Heat Transfer?

    Homework Statement Two infinite plates are kept at different temperatures T_{cold}<T_{hot}, with vacuum between them. A very thin plate, isolated from the environment, is inserted between the two plates. How will the net rate of heat emission from the hot plate to the cold plate change...
  20. K

    Force Experienced by Charges between Parallel Plates

    Hello, Is the force experienced by a charge at any point between two charged parallel plates the same? Just a preliminary step to my homework question, Let's say I have two parallel charged plates. (positive on top and negative on bottom with field lines going downwards.). Would all positive...
  21. P

    Electrostatic force between 2 distant parallel plates

    Homework Statement The problem is: If you have 2 rectangular plates 1cmx10cm each, which means that the area is A=10cm2=10-3m2for each plate; every plate holds a Constant positive charge of Q=+2x10-6C each; these plates are separated by a distance d=1cm=10-2m What is the electrostatic...
  22. J

    Capacitors with more than two plates?

    I am a mechanical engineer and not an electrical engineer, so feel free to snicker at my question. Can a capacitor have more than two plates? If so, what happens? Is it less efficient? How would a tripple- or quaduple-plate capacitor behave differently than a dual-plate capacitor, assuming...
  23. V

    Increase the distance between plates of a capacitor in direct current

    Hi. I've been studying in details how a microphone works. I've found a type of microphones where capacitor is used to record sound. The idea is simple. Increasing and decreasing the distance between the plates of a capacitor (sound waves) results in the changing capacitance. Being connected...
  24. N

    How much negative energy is that space between two non-conducting plates?

    The negative pressure generated in the Cashmeir effect suggest that negative energy can exist in small spaces between non-conducting plates. How much negative energy exist in a given amount of space as measured in units that refer to energy (as opposed to units of force created by the Cashmeir...
  25. K

    ES potential two parallel plates

    Derive the electrostatic potential between two flat plates in electrolyte solution. The surface potential at the plate surfaces is low. I think this problem uses the Poisson equation for electostatic potential, but the one I came up with was wrong. It involves the hyperbolic cos. (cosh)
  26. R

    Change in electric potential between 2 parallel plates

    Homework Statement A proton is released from rest in a uniform electric field of mag. 90000 V/m directed along the positive x axis. the proton undergoes a displacement of .2m in the direction of the electric field. Find the change in electric potential. Homework Equations no idea...
  27. P

    Can we have electrostatic levitation using capacitor type plates?

    Hi all, I am in the process of developing a science project. That is when I came across different types of levitation including electrostatic levitation. Maglev trains are a good example of magnetic levitation. We know that like charges repel each other. Its on the last sentence that I...
  28. A

    What Is the Mass of an Oil Drop Balanced Between Metal Plates?

    Homework Statement Two horizontal metal plates are 1cm apart in air. An oil drop bearing a charge of one electronic unit is balanced between the plates when the potential difference between them is 800volts. Find the mass of the drop. Homework Equations I may need to use some...
  29. M

    How Does an Electron's Speed Change in a Uniform Electric Field?

    Homework Statement An electron is projected with an initial speed 1.50×10^6 m/s into the uniform field between the parallel plates in the figure . Assume that the field between the plates is uniform and directed vertically downward, and that the field outside the plates is zero. The electron...
  30. M

    Uniform electric field paralell plates

    hi, I've just been reading a bit of physics to get myself ready to do a degree after a year of not a lot and was looking at uniform fields so i tried to prove that infinite plates have a uniform field however i seem to have disproved it with coulombs law. here's my logic, please explain the...
  31. C

    Capacitance, parallel plates, electric field

    Homework Statement To find the capacitance of parallel plates, I am first finding the E field using gauss. However I don't know what the gaussian surface will be. I don't think it will be a gaussian pillbox as the plates aren't infinite, but will it be a sphere?? On a side note, if I...
  32. J

    Fully Developed Flow between two parallel plates

    Hey you all, I have a practice exam problem which is causing some difficulty for me. Basically I have a fully developed flow through two parallel plates. One plate has a constant heat flux and the other plate is heavily insulated. I have found the velocity profile: U=2*Uinf*(1-r^2/h^2)...
  33. B

    What would happen if I take apart the plates of a charged capacitor?

    what would happen if I take apart the plates of a charged capacitor? Would the plates stay charged, or will the plates loose their charge? will the energy stored in the capacitor during charging stay stored in the plates though there is no more existence of electric field?
  34. T

    Electrons accelerated between two plates

    Homework Statement Electrons are accelerated between points A and B to the energy of 7.1keV, see attachment. The coordinate system was selected to have the origin at the startup point A. The electrons enter an area between two parallel plates where the magnetic field is established by...
  35. U

    Electric field between two charged plates

    Is there any possible way that an electric field between two positivly charged plates (charge is the same on both of them) could induce a charge in a conductor that is put in this field?
  36. R

    Capacitor how the plates are connected

    Homework Statement Capacitor C1 is charged so that potential difference between its plates is 20V. Another capacitor C2=33 microF has potential difference of 4 V. After plates of the capacitor that carry the charge of the opposite sign were connected the potential difference became 2V, find...
  37. K

    How Does Temperature Change Over Time Between Two Aluminum Plates?

    Hi, I have an easy problem for you I think but I'm not a specialist in thermo problems. Here is my problem. Homework Statement 2 plates in aluminum, one at T1=230°C and the other one at T2=30°C. In between, some air or something else (I don’t know yet). Homework Equations Equation...
  38. Z

    Charge on three metallic plates

    Homework Statement 3 metallic plates are placed at a separation d1 and d2 as shown in figure. A charge Q is given to the middle plate which is free to move, then A)it will slide towards left if d2>d1 B)it will slide towards right if d2>d1 The Attempt at a Solution I found out the charge...
  39. Z

    Electric field outside the plates of a capacitor

    Is there any electric field outside the region between the plates of a parallel plate capacitor? What about near the edges? Do we neglect that variation in deriving an expression for the field inside? The positive and negative charges appear only on one side of each plate so I don't think there...
  40. T

    Electric Fields Lines of a pair of Finite Parallel Plates

    Homework Statement Comment on the electric field lines of a pair of finite parallel plates (a) between the plates and (b) near the edges of the plates. Homework Equations The Attempt at a Solution
  41. A

    Two Parallel Conducting Plates with moving charge

    Homework Statement Two parallel conducting plates that are in deep space are brought to a potential difference of 3500 V, and a small pellet of mass 6.95 mg carrying a charge of 6.70 × 10-7 C accelerates from rest from the positive plate. With what speed will it reach the other plate...
  42. R

    Find Electric Field between Two Plates with Varying Permittivity

    We have a problem for our Electromagnetics class. It is the following "A parallel-plat capacitor of cross-sectional area A an thickness d is filled with a dielectric material whose relative permittivity varies linearly from \epsilon_{r}=1 at one plate to \epsilon_{r}=10 at the other plate...
  43. H

    Fluid Flow between parallel infinite plates

    Hello I am trying to understand some fluid mechanics I have two parallel infinite plates with fluid between the plates and some fluid above the plates. The fluid above the plates has a free surface exposed to the atmosphere. And we can neglect body forces. The fluid flow (steady and...
  44. G

    A charge accelerating between two plates

    Hi all, Suppose an alpha particle of 3.2 x 10-19 C accelerates from rest between two oppositely charged plates starting from the positive plate. The electric field between the plates is uniform equal to 39000N/C. The distance between the plates is 4.50 x 10-3m Does the alpha particle...
  45. P

    Fields at the ends of a parallel plates

    Why do the field lines bulge out at the ends of plates with finite lengths? I understand why the field is uniform between infinitely long plates but cannot extend the concept to plates with fixed length:( I know they have to bulge but why not bulge inwards rather than outwards?
  46. M

    Any current in an AC circuit if you moved the plates of a capacitor apart?

    capacitor question...(why does AC need a return path) say you have an ac power source (120 v) connected to a circuit which just has one parallel plate open air capacitor, with the plates separated by, say, 1 mm. you measure the current flowing through the circuit and you get some rms value...
  47. R

    Zero potential between two plates

    Say there are two charged plates opposite each other, 1m apart; one is +20V and the other is -20V. There is a point where we say there is zero potential, 50cm from either plate. I don't understand how we can say that a charge would have zero potential when we define potential energy as an...
  48. Z

    Work Done in moving the plates of a Capacitor

    Homework Statement Consider a parallel plate capacitor connected to a battery. You move the plates closer to each other. Will you do positive or negative work? The Attempt at a Solution As the plates are moved closer to each other, capacitance increases which increases the stored energy (V...
  49. R

    Uniform field between parallel plates

    Hey, I've recently been studying electric fields, and our teacher told us that the field is approximately uniform between two charged parallel plates, ie the force acting on a unit charge is equal everywhere. This doesn't seem to tie with everything else we've been taught; surely, as you...
  50. P

    Force between condensator plates

    Homework Statement how i can calculate force between condensator plates?
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