What is Plates: Definition and 621 Discussions

According to Latter Day Saint belief, the golden plates (also called the gold plates or in some 19th-century literature, the golden bible) are the source from which Joseph Smith translated the Book of Mormon, a sacred text of the faith. Some witnesses described the plates as weighing from 30 to 60 pounds (14 to 27 kg), gold in color, and composed of thin metallic pages engraved with hieroglyphics on both sides and bound with three D-shaped rings.Smith said that he found the plates on September 22, 1823, on a hill near his home in Manchester, New York, after the angel Moroni directed him to a buried stone box. He said that the angel prevented him from taking the plates but instructed him to return to the same location in a year. He returned to that site every year, but it was not until September 1827 that he recovered the plates on his fourth annual attempt to retrieve them. He returned home with a heavy object wrapped in a frock, which he then put in a box. He allowed others to heft the box but said that the angel had forbidden him to show the plates to anyone until they had been translated from their original "reformed Egyptian" language.
Smith dictated the text of the plates while a scribe wrote down the words which would later become the Book of Mormon. Eyewitnesses to the process said Smith translated the plates, not by looking directly at them, but by looking through a transparent seer stone in the bottom of his hat. Smith published the first edition of the translation in March of 1830 as the Book of Mormon, with a print run of 5,000 copies at a production cost of $3,000 (or 60 cents per book).
Smith eventually obtained testimonies from 11 men who said that they had seen the plates, known as the Book of Mormon witnesses. After the translation was complete, Smith said that he returned the plates to the angel Moroni; thus they could never be examined. Latter Day Saints believe the account of the golden plates as a matter of faith, and critics often assert that either Smith manufactured them himself or that the Book of Mormon witnesses based their testimony on visions rather than physical experience.

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  1. A

    I Do the plates of the capacitor exert a force on each other?

    Do the plates of the capacitor exert a force on each other due to opposite electrical charges? Consider a planet capacitor. A simple calculation shows that this force must be very large. If you are not convinced of the magnitude of the force, I will give a simple example.
  2. V

    Polarities of capacitor plates in a complex circuit

    (a) I think the top plate of C5 could end up with either + or - charge, and not necessarily + charge as shown. This is because the connected plates of C1, C5 and C3 form an isolated system to which we can apply the law of conservation of charge i.e. Total charge just before transient currents...
  3. J

    Moment of inertia question for two plates welded together

    If two plates of Aluminum (both are 2" tall, and 1/2" thick) were placed over each other (see photo 1) and then welded together all around the perimeter of the second plate (the blue one) as indicated by the yellow lines in photo 2, then would the moment of inertia be calculated as if the local...
  4. Pushoam

    Force between the plates of a capacitor with dielectric slab inserted

    The the electric field inside decreases due to the presence of a dielectric by a factor of dielectric constant K. Hence the force between the plates will decrease. Is this right?
  5. Astronuc

    Mag 6.4, Triple Point -Juan de Fuca (Gorda), N America, Pacific Plates

    M 6.4 - 12km WSW of Ferndale, CA https://earthquake.usgs.gov/earthquakes/eventpage/nc73821036/executive 2022-12-20 10:34:25 (UTC) 40.523°N 124.393°W 16.1 km depth https://en.wikipedia.org/wiki/Juan_de_Fuca_Plate#/media/File:Juan_de_fuca_plate.png Numerous aftershocks (Mag 2-4) occurring...
  6. A

    Problem Connecting Core with Face Plates (APDL)

    Hello everyone, I would like to know if anyone could help me with my apdl model. I have created a model of a honeycomb sandwich panel but the solution is not converging, is there something that I should pay attention to? I have connected the core and the plates simply with NUMMRG command...
  7. L

    Maximum charge on the plates of a capacitor

    What I have done: The electromotive force due to Faraday's Law is: ##\mathcal{E}=-\frac{d\phi(\vec{B})}{dt}=\frac{d}{dt}(Ba^2)=a^2\frac{dB}{dt}=-10^{-4}V.## In the circuit, going around the loop in a clockwise fashion: ##\oint_{\Gamma}\vec{E}\cdot d\vec{l}=-\frac{d\phi(\vec{B})}{dt}\Rightarrow...
  8. A

    Understanding Electric Field of Positive & Negative Plates

    I am confused with the solution. It says ##\vec E = \frac{\sigma}{\epsilon_0}##. Shouldn't E = ##2*\vec E = 2*\frac{\sigma}{\epsilon_0}##? Electric field of the positive plate and electric field of the negative plate.
  9. T

    Fate of Sinking Tectonic Plates

    Just stumbled across this and thought it was interesting. https://scitechdaily.com/fate-of-sinking-tectonic-plates-has-long-puzzled-scientists-now-theyve-found-an-answer/ The original is behind a paywall at: https://doi.org/10.1038/s41586-021-03937-x Cheers, Tom
  10. C

    Future of tectonic plates

    Hi PF! I'm teaching a little unit on tectonic plates and have a question about the projected pattern of future plates. I know that plates can be broken into 2 (or more) new plates as the result of a continental rift. Our textbook also says that "The Atlantic seafloor may eventually become old...
  11. Dario56

    I Fluid Viscosity & Viscous Friction Between Plates

    When fluid is placed between two parallel plates such that one plate is moving and other is stationary, fluid will start flowing. Between plate and the fluid there is viscous friction given by equation: $$ F = -\eta A \frac {dv} {dy} $$ where $ \eta $ is fluid viscosity, $A$ is area of a plate...
  12. Jrads

    Charge between parallel plates

    Electric field between the plates V=4x10^3 d=0.02 E=4x10^3/0.02 E=2x10^5 V/m Calculate the force on charge -e -e = -1.602x10^-6 Me = 9.11x10^-31 F=qE F=(1.602x10^-6)(2x10^5) F=0.3204 N Using F=ma a=F/Me a=0.3204/9.11x10^-31 a=3.517x10^29 m/s Time = distance / speed T=.01 (half distance of...
  13. meher4real

    Electric field between two parallel plates

    [New poster has been reminded to show their best efforts to work the schoolwork problem when starting a homework thread] My question is : An electron beam with velocity vector v = (0; 0.6x10^8 ;0) m.s enters between two oppositely charged plates parallel to the xz plane. - How large is the...
  14. S

    Electric fields of charged plates

    I thought it might be the case that the "2m away" wasn't applicable as the electric field doesn't change if the point away is less than the length of the plate, so I thought I should use the equation listed. All examples I can find talk about two charged plates, or the effect on cylinders...
  15. Roger Dalton

    Calculating Magnetic Energy Between Plates

    The current density between the plates is J = 1 A/m2. So, I have to calculate first the magnetic energy in the whole space. Out of the sheets, there is no current, so the magnetic energy would be 0 in that places. Hence, U = J(1/2) \int_{inside the plates}A(r)dr, where A(r) is the vector...
  16. larginal

    Electromagnetics: find D,E,P between two parallel conducting plates

    I tried to solve this problem on my own, but I'm not sure whether I solved correctly or not. it is electromagnetics homework from my Uni, and it is pretty tough for me. I attached the image of the problem and how I tried to solve this one. I hope somebody will give some feedback.
  17. Z

    Potential Gradient for individual charges and parallel plates?

    In my book, the potential gradient for a charge placed anywhere in space is defined as: E = -V/r HOWEVER, for parallel plate (capacitors) the potential gradient is defined as E = V/d (V being the potential difference). How come there's no negative sign for the potential gradient of the parallel...
  18. iVenky

    Dielectric and Attraction Between Oppositely Charged Plates

    I am not able to intuitively understand the reasoning behind why the presence of dielectric between oppositely charged plates, let's say, reduces the force of attraction between the plates. I understand to some extent that electric field lines prefer to flow through dielectric (or insulator)...
  19. SebastianRM

    Slip Conditions for flow between Parallel Plates

    The problem states: Two parallel plates separated by distance h, the plate at the top moves with velocity V, while the one at the bottom remains stationary. My initial approach was: I considered, ##du/dy = V/h## and for the shear stress ##\tau = \mu \frac{\partial u}{\partial y}## For...
  20. B

    Motional EMF for loops of wire vs conducting plates

    I'm in an intro E&M class, and I'm trying to distinguish between Motional EMF for loops of wire and conducting plates. This question might be kind of silly, but are Eddy currents pretty much the same thing as induced currents in a loop of wire? More specifically, what I am trying to ask is if...
  21. LCSphysicist

    Why do we need to equate the rate of energy of the second plate to zero?

    First i computed the rate of energy wrt time of the second plate: $$dq_{2}/dt = A \sigma ((373)^4/2 + (273)^4/2 - T_{2}^4)$$ Equaliting it to zero we get the answer. But i am not sure why do we need to equality it to zero. The q arrow on the figure suggest me that it is conservation of energy...
  22. patric44

    Questions related to the current between the plates of a vaccum tube?

    hi guys i have an assigment of deriving the current between the plates of a vacuum tube as a function of the potential bias applied on the upper plate from what i had found this relation is called Child-Langmuir law and states that : $$I = K V_{d}^{3/2}$$ from what i find online i can derive it...
  23. M

    Electron between two parallel plates

    a) E = s / E0 so s is 4.87E-9 b) The electron will be projected at up angle since its charge is negative ( not sure if there's another reason behind it) c) Initial speed: V0 = 5 * 10^6 * cos(theta) + 5 * 10^6 * sin(theta)The force suffered by the electron is: Fy = q*Ey Fy = -1.602*10^19 *...
  24. archaic

    Current leakage between the charged plates of a capacitor

    1)$$\frac{Q}{\Delta V}=\frac{\kappa\epsilon_0A}{\ell}\Leftrightarrow\Delta V=\frac{Q\ell}{\kappa\epsilon_0A}$$$$I=\frac{A\Delta V}{\ell\rho}=\frac{Q}{\kappa\epsilon_0\rho}$$ 2) The charge is decreasing by ##\Delta Q##, so ##Q(t)=Q-\Delta Q##.$$I=\frac{\Delta Q}{\Delta t}\Leftrightarrow\Delta...
  25. archaic

    Inserting a dielectric between the plates of a parallel plate capacitor

    a)$$C=\frac{\kappa\epsilon_0\ell x}{d}+\frac{\epsilon_0\ell(\ell-x)}{d}=\frac{\epsilon _0ℓ\left(\kappa x+ℓ-x\right)}{d}$$ b)$$U=\frac{1}{2C}Q^2=\frac{dQ^2}{2\epsilon _0ℓ\left(\kappa x+l-x\right)}$$ c)$$F=-\frac{dU}{dx}=\frac{dQ^2\left(\kappa -1\right)}{2\epsilon _0ℓ\left(\kappa...
  26. Sj4600

    Electric Potential Energy Question: Electron and Proton accelerating between charged plates

    Ve=0m/s Vp= 0m/s Qe/Qp= 1.60E-19 Me=9.11E-31 Mp-1.67E-27 Ive pretty much gathered all of the equations I think I need to solve the problem. I just am stuck. The last step I realize that the forces would be equal to each other so I have mp x ap = me x ae but then when I try to solve for the...
  27. R

    Electric Field Between two Parallel Conducting Plates of Equal Charge

    Attached is the subsection of the book I am referring to. The previous section states that the electric field magnitude at any point set up by a charged nonconducting infinite sheet (with uniform charge distribution) is ##E = \frac{\sigma}{2\epsilon_0}##. Then we move onto the attached...
  28. oondi

    Electromagnetism: Force between two charged plates

    Hello, I need to find the force between the two metal plates, one is charged positively, and another is charged negatively. I have to use surface integration, but then I get two surface integrations because of the two differently charged plates. Now I am confused. Please help me. Thank you in...
  29. J

    Point-like charge between grounded plates: Induced charges

    I don't understand why moving charge doesn't affect the magnitude of induced charge. Could someone explain why it is possible? Thanks in advance.
  30. S

    Interference pattern for two glass plates closely separated and tilted

    hi, i know you have to use 2t/lambda= m/2 to get the answer of 10.9 um. However i was taught that there would be phase difference caused by reflection, since n1(air)< n2(glass). SO the equation in my head would be 2t/lambda - 1/2= m/2. Can someone explain why I'm wrong?
  31. FEAnalyst

    Radiation heat transfer between parallel plates

    Hi, the approximate (not accounting for plate size and separation distance) formula for heat flux exchanged via radiation between two parallel plates is: $$q=\frac{\sigma (T_{1}^{4}-T_{2}^{4})}{\frac{1}{\varepsilon_{1}}+\frac{1}{\varepsilon_{2}}-1}$$ where: ##\sigma## - Stefan-Boltzmann...
  32. F

    The real reason for a capacitor having the same amounts of + and - charges on the two plates

    Most textbooks say that a capacitor whether it be a single one or one in series/parallel should have equal amounts of + and – charges on both plates and that they mostly conclude the + charges attract the same amount of – charges on the other plate without giving any reason. Now I claim that...
  33. r-swald

    Find how far a proton travels between capacitor plates

    I first attempted to use kinematics, but to find acceleration I would need to find the force either by finding the e-field first and multiplying it with q, or just kQq / r^2. However, I was not given second charge or surface charge density. Is there another way I could go about making the...
  34. E

    Gauss' law for a physical capacitor with finite thickness plates

    In derivations of capacitance it is standard to consider two oppositely charged, infinitely thin sheets. If we construct a Gaussian cylinder across one sheet, we obtain ##E_{1} = \frac{\sigma}{2\epsilon_{0}}## for one sheet, and then we can superpose this field with that from the other at an...
  35. Mircro

    Material between capacitor plates - viewed as two capacitors in series

    This is a second grade high school problem, translated from my native language. I don't have a problem with calculating, but with understanding the concept. There is an instruction with the assignment that says: The capacitor can be viewed as a combination of two capacitors in series with...
  36. WMDhamnekar

    MHB Determine how many licence plates would cost $100

    In a certain state of a certain country, each vehicle license plates have exactly three letters followed by three digits. We are told that to produce such a license plate, it costs $n for each digit n>0 and $10 for each digit 0. For letters the cost is proportional to the position of the letter...
  37. N

    I Cavity resonances between two long parallel plates

    Consider two rigid and infinitely long parallel plates (say they are of infinite length in X direction, so running from -inf to +inf in X axis) separated by a distance d (say measured in Y-direction). Let the space between the plates be filled up with a fluid that supports acoustic waves. If we...
  38. F

    B field between the plates of a charging capacitor (Ampere's law)

    A standard example consider a capacitor whose parallel plates have a circular shape, of radius R, so that the system has a cylindrical symmetry. The magnetic field at a given distance r from the common axis of the plates is calculated via Ampere's law: \oint_\gamma {\mathbf B} \cdot d{\mathbf...
  39. M

    MHB Possible combinations for six digit license plates, numbers 0-9 and letters a-z.

    Hi, I'm not sure if this is the correct forum so if I need to post elsewhere please let me know. I'm having trouble with calculating the possible combinations for six digit license plates, numbers 0-9 and letters a-z. I know the overall combinations are 1,947,792 when repetition is allowed...
  40. WhiteWolf98

    Flow Rate (Q) of Viscous Flow between Two Plates

    I know how to derive the formula, but I have no idea how to actually use this. Where it says ##50~cm## wide, I'm not sure if that's in the x-direction or the z-direction. ##W##, the width in the equation, is in the z-direction. ##\mu## can be calculated, but I'm not sure what the pressure...
  41. S

    Calculate the number of plates required for a heat exchanger

    Cooling water inlet temp is 4 degrees C Cooling water outlet temp is 80 degrees C Density of water is 1000 kgm-3 Specific heat water is 4.2kJkg-1K-1 Density wort is 1060 kgm-3 Specific heat wort is 4.0Kjkg-1K-1 Overall heat transfer coeff is 3000Wm-2k-1 Area of each plate is 0.75m2 For water...
  42. Tryhard314

    Why does the potential of A decrease when plate B is nearby?

    Summary:: if Plate A had a potential of 9V, This means as We approach a unit charge from +Infinity to A we have to do this precise amount of work Now we remove plate A, And replace it with plate B that has a potential of -9V Again that means to go from +Infinity To B we actually gain energy, or...
  43. O

    How can I evenly heat a series of metal plates to a controlled temp?

    (In opening, hi. I'm a lawyer, not a physicist, and I'm entirely out of my depth here.) I need to make roughly 8 wooden frames (19 inches x 1-1/16 inches x 9-1/8 inches). Into each, I'd like to place a thin metal plate with hexagonal cells (5.27 mm cell diameter) pressed into them. I need to...
  44. Stephen Miller

    Max Deflection Hand Calculations: Find 1.734in Plate Bending

    Summary: Max Deflection Hand Calculations I have to do a project that involves FEA on a thin plate in NX NASTRAN 11, finding the max deflection, and then proving that answer with hand calculations. The max deflection is 1.734 in. I have absolutely no idea how to do the hand calculations...
  45. M

    Find the charge on the plates of a parallel-plate capacitor w/ dielectric

    This is an online HW question so maybe my digits are just off from rounding or something, but I don't know why I am not finding the correct answer. I got Q = 6.9e-8 as the magnitude of charge on each plate. I basically just needed to calculate the original capacitance of this capacitor using c...
  46. M

    Prove to me how capacitors in parallel can have the same V across plates

    *If at any point I say something incorrect or its clear I don't have the right understanding of something, please point it out and correct me. I need to be sure I'm understanding it all correctly. So please don't answer unless you're willing to read this entire post* So I know capacitors in...
  47. M

    Find the E-Field between plates when given only given part of the total voltage

    I'm really unsure about how to solve this because I am not given the total voltage between the plates. The voltage given (693V) is at a point that is 7.85 cm away from the zero volt plate. If I was given the total voltage between the complete distance between the plates (10 cm), then I could...
  48. jisbon

    Electron traveling between charged plates

    So I can understand how to find out velocity of electron moving between these 2 plates, by using: How am I supposed to find the 'minimum' velocity though?