Outside Definition and 469 Threads

Zee's QFT in a Nutshell makes a short comment in the first chapter about the possibility of particles tunnelling outside their light cone - is there some probability that a particle could do this? I know the neutrino thing has been debunked as a faulty cable, but did not see this offered as an...

Is it possible for EM radiation to exist outside the EM spectrum? I'm aware of the different frequencies at which energy can be radiated eg. radio, infrared, and gamma. But is it possible for objects to absorb or release energy at subradio or supergamma frequencies? Or is there a physical law...

Homework Statement \int_{|z-2i|=2} = \frac{dz}{z^2-9} 2. The attempt at a solution I know that the contour described by |z-2i|=2 is a circle with a center of (0,2) (on the complex plane) with a radius of 2. The singularities of the integral fall outside of the contour (z+3 and...

Given the following information: a 6.10m long snorkel, density of air = 1.21 kg/m^3, atmospheric pressure = 1.013 x 10^5 P, g = 9.8 m/s^2 and density of seawater = 1.03 x 10^3 kg/m^3, how would you calculate the pressure outside the scuba diver's lungs? Would it be anything to do with this...

I am wondering what astrophysicists do outside of academia. also what would their salary be with a PHD?

A ball A of mass makes a head-on elastic collision with a second ball B (at rest) and rebounds in the opposite direction with a speed equal to one-fourth its original speed. What is the mass of the second ball B? I think an appropriate equation for this is v(1)= u(1)*(m(1)-m(2))/(m(1)+m(2))...

Hi, I live in 6th floor of an apartment. To prevent birds from pooping beside my window, I hang some unlabeled CDs along a string outside the window. The window is facing east, and people start complaining about it, that it might cause fire. I wonder if that is even possible? I personally do...

The Poisson Integral Formula is a representation of the bounded solution of the Dirichlet problem for Laplace's equation in the interior of the disc. Derive the corresponding formula for the Dirichlet problem in the exterior of the disc, again assuming that the solution is bounded.So we derived...

Homework Statement Homework Equations torque = MxB. The Attempt at a Solution as the ring is completely outside the magnetic field, B=0... even if its not, M=iA, and since the charge is static, i=0. so, as per my thinking, ans. should be 0...

Homework Statement In case of having a conductor (spherically shaped and uncharged) and an irregularly shaped hole inside it with a charge at an arbitrary point, I am asked to find the electric field right outside the conductor sphere. Homework Equations Gauss's law ∫EdA=...

Homework Statement Find equations of both the tangent lines to the ellipse x2 + 4y2 = 36 that pass through the point (12, 3). Homework Equations The equation of an ellipse is x2/a2 + y2/b2 = 1. I converted the given equation to x2/36 + y2/9 = 1 by dividing each value by 36. The...

Homework Statement The charge desnsity within a uniformly charged sphere of radius R is ρ = ρ0 - ar2, where ρ0 and a are constants and r is the distance from the center. Find an expression for a such that the electric field outside the sphere is zero. Homework Equations Electric Field...

Just finished this short film. Sorry for the irrelevance but I'm quite excited and would love some feedback! And I do break the laws of physics in parts ;) https://www.youtube.com/watch?v=XlTGtoevyBk Only 2 minutes and you can stop watching if you get bored! Love to hear your thoughts...

Can someone please tell me if there is name for focusing the outside light to a point down a tube then magnifying it back showing the outside view? E.g. having the lenses focus on a hill side then focus down a 1 meter tube then enlarge onto wall. If there is no name for this what type of...

So I've been reading Hehl's Foundations of Classical Electrodynamics - which builds up Electrodynamics from a six of axioms - and their proof that the conservation of charge alone is sufficient to derive the inhomogenous Maxwell equations got me thinking - why don't these extremrly basic...

Homework Statement The potential outside of a spherical conductor is given by V = keQ/r. Using Er = -dV/dr, derive the electric field outside this charge distribution. The Attempt at a Solution I attempted to take the negative derivative of V being -1/(r2) and then multiplying it...

Homework Statement A long cylindrical shell of radius R = 12.3 cm carries a uniform surface charge 4.60E-6 C/m2. Using Gauss's law find the electrical field at a point p2 = 16.5 from the center of the cylinder. Homework Equations EA=q/epsilon0 The Attempt at a Solution This is what...

If this question has been posed before I apologize, but is it possible for any objects and/or entities that are atemporal to exist?

Homework Statement A student makes an electromagnet by winding 320 turns of wire around a wooden cylinder of diameter 4,80 cm. The coil is connected to a battery producing a current of 4.20 A in the wire. At what axial distance z>>d will the magnetic field of this dipole be 5.0 μT? Homework...

[b]1. Three boards are in the x axis. the middle one is in x=0 and charged in a positive sign density is: σ. the other 2 boards are in : x=d and x=-2d. This 2 boards are grounded. The question is why outside the boards the ElecField is 0? I though that i don't waste energy to bring an...

Hello, I've just discovered these forums within the last hour or so. I am rather intrigued and I hope to learn something in making myself familiar with the concepts and theories that fly around here. However the reason I've stumbled across these forums is because I need a question answered. I'm...

It is said nothing can escape the Event Horizon, not even light. How about an entangled pair that is inside the event horizon and outside it. Would they still be entangled such that they still form correlations?

Hi all. I am shortly to begin work on my engineering FYP in automatic control and I'm hoping for some advice to point me in the right direction. The project will initially be an electromagnetic suspension rig (cylindrical winding with soft core suspending a permanent magnet below it via...

Specifically, does our Universe exist on the inside "skin" of a bubble or the outside "skin" of a bubble? I'm sure this has something to do with M-Theory or brane cosmology, right? I'm curious.

Homework Statement Find the electric potential inside and outside a spherical capacitor, consisting of two hemispheres of radius 1 m. joined along the equator by a thin insulating strip, if the upper hemisphere is kept at 220 V and the lower hemisphere is grounded Homework Equations...

Homework Statement See figure attached. The author claims the field outside this infinitely long solenoid with N' turns and a current i(t) flowing through it is 0, but he doesn't explain why. Why is it 0? Is there an intuitive reasoning behind it? Homework Equations N/A The...

I am trying to model the cooling of an object (for example, a sheet of glass) placed outside at night. At the moment I am only considering heat loss by radiation. I know that the net radiation from the object will be: Rnet = Robj - Rsky where: Rnet = the net radiation from the object...

If it were true that non-inertial motion, such as spin, is required for magnetism to exist, then one could say that a lack of non-inertial motion implies lack of magnetism. However, whether a separate body is traveling inertially or non-inertially in relation to spacetime is not something...

i've heard from people: the real world is nothing like university, engineers don't really use much except for formulas and computers do most of it anyway. How true is this? I personally hate maths but i like engineering, trying to just get through it. Also since i hate maths, is it even...

If a conducting sphere has a negative net charge and there is a positive point charge at the center of the sphere, what charge would you use to find the Electric Field at a point outside the sphere? The equation is E=kq/r^2. Would I use the net charge of the sphere, or do I need to...

Hi everyone, Well everything is in the title. Answers are not clear on the net and I cannot figure it out myself.

Hi there. I have this problem which I was trying to solve, but I couldn't fit the boundary conditions. The exercise says: Two conducting spherical shells with radii a and b are concentrically disposed and charged at potentials φa and φb respectively. If rb>ra, find the potential between the...

I have very little background in physics and I only have basic calculus under my belt... but I can't seem to get this thought out of my head. There is no mathematical proofs here, no experimental evidence, not even any real evidence for theory, however I'd like to hear your thoughts on the...

when the humidity meter on my back porch reads 57%? May be a silly question but I don't know. I thought when the humidity exceeded 100% the excess moisture condensed out of the air and that's what we call precipitation. Obviously either my meter or my understanding is faulty?

After a lot of searching and coming close to getting a job in the field I want, I have accepted the fact that this is unlikely to happen. Truly disappointing. I do have the opportunity to obtain a job outside my field. My concern is graduate school. I want to work for about a year, then go...

Hi, When considering a long term career, how does one chart a course that will allow working outside of an office for a substantial amount of the week/month/year/life? A very general, open question, but as I interview and gain experience with more and more engineering firms I realize that...

So this last winter, my roommates and I left a bunch of freezy pops outside to get cold fast (the temp was -20F). They were in clear plastic and may have been exposed to the sun. After about a day, we went to pick them up, and they had all turned clear. They stayed clear even when brought...

Nuclear power plants as well as power plants in general are not self-sufficient in terms of electricity. If a nuclear power plant loses outside electrical power, the plant must then be powered with emergency diesel generators which typically have about 10-12 hours worth of fuel, and then...

Hi all, I have never had a server OS before but just got myself a new mac mini server with Lion server installed. The point of this was so I could ssh my machine from work and access my files from wherever I am. Sadly, I seem to be only able to ssh my machine when I am on the same wireless...

Area in cardioid and outside circle -- Using Double Integral Homework Statement Find the area inside of the cardioid given by r = 1 + cos\theta and outside of the circle given by r = 3cos\theta. Homework Equations \int\intf(x,y)dA = \int\intf(r,\theta)rdrd\theta not really relevant...

Since the capacity of an air conditioner is a function of outside air temperature, does it follow that greater efficiency will be achieved by putting the condenser under shade rather than out in the open or on a hot roof? Or does the casing of the unit provide adequate shading to make this...

Would you like the 105 F we had yesterday? I'll trade.

Hi I want to find the magnetic field result from DC current flow through the rectangular transmission line numerically by using the finite difference. the solved equation is curl curl A =µ J , with div A=0, and J is a uniform current on the crosssection. I implement the MATLAB code , but...

Homework Statement An infinitly long conducting cylinder of Radius R carries a inform surface charge of (lambda per unit length) determine the electric field strength inside and outside the cylinder Homework Equations integral (E.ds)= q/e0 The Attempt at a Solution im not really sure what...

Although the title mentions biology the answers I need are from physics. If I have understood it correctly Argentinian Electroneurobiology assumes mind to take place at the actions of a force field overlapping the electromagnetic field of the brain. I think. An exposition...

Thread title says sums up my question. I'd like to know if there are many paying jobs that focus almost exclusively if not entirely on research. I'm interested in theoretical research jobs in math or physics other than being a professor. I don't want to teach, and it has become very hard to...

From my understanding there is no 'proof' that there is an 'outside the Universe'. My question is, does the latest scientific data imply that there is or is not? Do we have any good reasons to believe are things outside of our Universe or not? Please elaborate. Thanks

Hi, Is there a fairly even star (or galaxy) density in every direction we look, ignoring our own galaxy? Or are there some directions where our OU seem denser than others?

The french IRSN just released a new report concerning the estimated contamination around DAICHI, i extract this map for the Cs contamination based on SPEEDI/MEXT estimations. The complete report is here (french)...

Sorry if my question seems naive, but is it theoretically possible to be somewhere outside the universe? (Ignoring our own limitations in getting there...) I'm pretty sure the answer is no, but I'd rather learn than assume.