Cavity Definition and 260 Threads

Hey there, I recently solved for the resonant modes in a 3d metal box. Thats nice, but I was wondering about how to actually excite the modes (its a sealed metal box) Supposing I actually excited these modes by shining incident em radiation such that a portion [of the incident wave]...

Homework Statement A charge distribution has the shape of a very large disk of thickness 3d. This disk has three layers of uniform densities \rho_{1},\rho_{2},\rho_{3} and thickness d each one. Within the layer with density \rho_{2} exists a tiny cubical cavity in such a manner that two of...

Homework Statement Well, there are two problems, both of which would allow me to receive extra credit in my college physics class! Both are rather descriptive, so I have linked an image to it. http://img87.imageshack.us/img87/9570/1000497y.jpg" Homework Equations For the first, I was...

Here's an interesting article about a new breakthrough in the manufacture of a superconducting radio-frequency cavity: http://nextbigfuture.com/2009/09/superconducting-radiofrequency-cavity.html If this new cavity were tested for EMdrive purposes, could it reveal a new mechanism for...

Homework Statement A cylindrical cavity oriented along z axis with length of 2 m has a filament in it upon which a current of 10 A is impressed. Cavity is perfectly conducting whereas it is filled with lossy dielectric. Electric field on the cavity is given as: [FONT="Arial...

The diagram accompanying this post shows a cylindrical column bored at right angles to a flat surface. Let’s say the material is a block of brass with a hole drilled in it. The arrow represents a fast moving stream of compressed air. As the air passes over the top of the column a high pitched...

Q6. Inside a fixed sphere of radius R and uniform density d ,there is a spherical cavity of radius R/2 such that the surface of the cavity passes through the centre of the sphere . A particle of mass m is released from rest at centre B of the spherical cavity. Calculate the vel. withwhich the...

1. The Question An isolated conductor of arbitrary shape has a net charge of +10\times10^{-6}C. Inside the conductor is a cavity within which is a point charge q = +3\times10^{-6}C. What is the charge on the outer surface of the conductor? 2. The attempt at a solution On cavity wall...

Is the resonance frequency of a magnetron cavity purely a function of its geometry? Thanks!

Why is it that an antenna/waveguide is only connected to one cavity in the magnetron, such as in a microwave? Are the resonating RF waves in the other cavities wasted then? Thanks! Edit: Also, are magnetrons always thermionic diodes?

Homework Statement Prove that the quality factor of a rectangular cavity resonator which is filled with a lossy dielectric but has perfectly conducting walls, is given by Q = \frac{1}{\tan\delta} where \tan\delta is the loss tangent, i.e. the ratio of the imaginary part of the dielectric...

could someone help me get started on a problem solving the photon lifetime in a cavity? i have 4 optical paths

Question: An infinite cylindrical wire with radius 2R caries a uniform current density J=Jz, except in an infinite cylindrical hole parallel to the wires axis. The hole has a radius of R and is tangent to the exterior of the wire. Calculate the magnetic induction B everywhere inside the hole...

Homework Statement A charge q is uniformly distributed over the volume of a solid sphere of radius R. A spherical cavity is cut out of this solid sphere and the material and its charge are discarded. Show that the electric field in the cavity will then be uniform, of magnitude kqd/r^3, where...

Hi, I am trying to work out the resistances for the following cavity wall. I am having to work backwards. I have the U value, which is 0.48. The brickwork is 103mm, the insulation in cavity is 50mm, lightweight concrete block is 100mm and plaster board is 13mm. I know total thickness...

Homework Statement Show the electric field inside an empty cavity in a conductor is zero, even if there is a charge outside the conductor. If a charge is placed inside the cavity, will there be an electric field outside the conductor. Explain Clearly. Assume that both the conductor and cavity...

Hello, I'm learning EM from Bleaney & Bleaney and got stuck on Ex2.1 (can do Ex2.2-2.7, though...) - If the polarization charge on the surface of a spherical cavity is -s.cos(theta), prove that the field strength at the centre is s/3e0. If I expand V(r) within the cavity as A.r.cos(theta) +...

Homework Statement A long straight wire of radius R carrying a current I has a circular portion of radius a cut out at a distance d from the center, as shown in the picture. Find the magnetic field inside the cut-out portion. Homework Equations magnetic field equation (I can't write it...

A laser cavity consists of a couple mirrors, a bunch of metastable molecules and some radiation. What's the partition of energy between molecules and radiation at equilibrium?

cavity on a water surface A vertical air jet from a straw produces a cavity on a water surface. What parameters determine the volume and depth of the cavity?

hi everybody I have one doubt as what is the meaning of 2d driven cavity flow?

Homework Statement Basically, the problem states that a cavity at temperature T is emitting EM waves isotropically in all directions (with frequency distribution of Planck's Law). If the time averaged density is <e>, find the value of d<S>/dw where w is the solid angle and the quantity is the...

Homework Statement A uniformly charged sphere (center O1) with radius a and charge +Q has an off-center cavity within it (center O2) with radius b. Show that the electric field within the cavity is uniform and is directed along the line of centers, according to the equation: \vec{E} =...

Gauss' Law - Sphere with spherical cavity - Please help Homework Statement A sphere of radius 2a is made of nonconducting material that has a uniform volume charge density . (Assume that the material does not affect the electric field.) A spherical cavity of radius a is now removed from the...

Homework Statement The polarization charge on the surface of a spherical cavity is - \sigma_e cos(\theta) at a point whose radius vector from the centre makes an angle \theta with a given axis Oz. Prove that the field strength at the centre is \frac {\sigma_e}{3 \epsilon_o} parallel to...

In a cavity 12.5 cm by 3.9 cm, with Y being 12.5 cm and X/Z being 3.9, how would you calculate the resonance for that internal volume. The volume is filled with air and the sidewalls are not rigid. This is also assuming that one end is open. I can, of course, give more information if it's...

Homework Statement Considering a cylinder of radius, R, and length D with uniform charge density p containing a spherical cavity of radius R/2. Find the field in the cavity. The cavity sits on one side of the cylinder so that it's diameter spans from the concave face of the cylinder to the...

The figure shows a cuboidal shaped conductor inside which there is an ellipsoidal cavity. The center of the cavity is at the center of the cuboid. Link to figure: http://www.picscrazy.com/view/1qtB9 A charge qo is kept at the center of the cavity. I am showing two positions 'A' and 'B'. MY...

http://optics.ph.unimelb.edu.au/atomopt/publications/littrow_rsi_vol72_p4477_2001.pdf The picture of the ECDL I explain can be found from the above web site. The purpose of piezo is to change the cavity length of the diode laser, so that the wavelength can be varied. From the picture...

hi , I am confused with these two terms microwave cavity and microwave chamber . Some say that the microwave chamber inside which food gets cooked acts like a resonant cavity ( which I believe is not true ) because resonance must best be avoided inside the chamber .Resonance I think...

An irregularly shaped chunk of concrete has a hollow spherical cavity inside. The mass of the chunk is 38 kg, and the volume enclosed by the outside surface of the chunk is 0.025 m3. What is the radius of the spherical cavity? I think you have to find the surface area to solve for the radius...

An insulating sphere of radius 5.00 cm , centered at the origin, has a uniform volume charge density 3.05 uC/m^3 . There is a spherical cavity cut out of its center of radius 2.00 cm. Well i know to use Gauss' Law: Φ = ∫E∙dA = Q/ε where Φ is the electric flux, E is the electric field, dA...

Hi, I know this is dumb question, and I should be able to figure it out and move past it, but I can't. The optics book I have begins its treatment of Fabry-Perot cavities by considering the case of an undamped optical resonater (perfectly reflecting mirrors). Here's a quote from it: If that...

Hi, So I have a lab question for which I have to drive a formula to find the optical cavity length of a laser, L . I have results from testing the fringe patterns when I move one of the mirrors in a Michelson interferometer. It shows the typical \frac{\sin x}{x} pattern. To find the cavity...

Inside a spherical cavity centered at the Earth's center, is the space-time curvature is 0 or not 0? Would the clock run more slowly?

In order to produce coherent laser light is it necessary that the length of optical cavity between the mirrors is a multiple of the wavelength of laser light? I cannot see how otherwise the laser been could bee coherent. On the other hand I don't see how it is possible to place the mirrors with...

Homework Statement A point charge of -2.09*10^(-6) C is located in the center of a spherical cavity of radius 6.54 cm inside an insulating spherical charged solid. The charge density in the solid is 7.36×10^(-4) C/(m^3) . Calculate the magnitude of the electric field inside the solid at a...

Homework Statement The electric field inside an empty cavity in a conductor is zero. Is this statement true no matter what the shape of the cavity? Why or why not? Homework Equations Electric field equation. E = kQ / R^2 The Attempt at a Solution I can't seem to figure out if this...

I am attempting to make a cavity microelectrode in which i will test the electro chemistry of polyaniline powder before moving on to other chemicals. I have read numerous papers on the subject. I am having a major setback in my aim: i need contact between my gold wire and the voltameter (as...

Suppose one has a solid metal body (in static eq'm) with a cavity inside it. Assume the cavity has no charge in it. This is how one could prove that there are no fields inside the cavity: choose two points A and B, both in the solid part of the metal body. Follow a path through the metal...

Inside a spherical cavity centered at the Earth's centre, the space-time curvature is 0 or =/= 0? I know Newtonian gravitational field is omogeneously 0, so no field variation, but does GR give a different answer?

A positive charge Q = 2800.00 C is uniformly distributed over the volume of a sphere of radius R = 6.00 m. Suppose a spherical cavity of radius R/2 is cut out of the solid sphere, the center of the cavity being a distance R/2 from the center of the original solid sphere (see figure). The cut-out...

Im studying gain saturation for homogeneous and inhomogeneously broaded transitions. Im a little confused bout the logistics of laser operation regarding the gain in the cavity. So from ground state, the atoms are optically pumped to produce population inversion(4 level system) where...

I have a quick question. I recently did an E&M problem in which I was given a cylindrical conducting wire of radius a, in which someone bores an off-center cylindrical cavity of radius b (the center of the smaller circle is offset from the center of the wire by distance d). I'm asked to find...

Suppose I had a uniformly charged sphere of some density, inside this sphere at some position there is a cavity of some radius. If I wanted to then find the Electric field somewhere, like say the surface of the sphere, how would I approach the problem? Heres what I did. I pretended the cavity...

In reading about the “Ultraviolet Catastrophe” in dealing with black body radiation, my book says that at the ultraviolet frequencies and beyond, the Rayleigh-Jean equation for the energy density of the radiation would be infinite (and thus a catastrophe). If this is the Rayleign-Jeans...

Homework Statement If we have a cavity filled with black-body radiation, an this is placed onboard a relativistic rocket (uniform linear motion). I want to yield the transformation laws (from the proper frame S' joint to the rocket and moving with constant velocity V in respect to a coordinate...

Homework Statement The textbook claims 'An air caivty between a brick outer wall and the inside wall helps to insulate from heat and cold.' It asks to explain in terms of heat conduction. Homework Equations noneThe Attempt at a Solution Is it because it takes a certain amount of energy to get...

Hello folks, I would like to know whether or not the cavity axial-mode frequencies have any influence on the frequency output of the laser beam. I suppose that the atomic transition from excited state to ground state is the only occurrence responsible for the wavelength, whereas the axial-mode...

Hi all My question arises in the context of a photon which is emitted by an atom located inside a cavity. From quantum mechanics, a photon is a quantum of an electromagnetic mode, but we also use the definition which says that the photon is what is released by an atomic system when its...