What is the limit of classical electrodynamics?
Hello everyone, I was wondering about the following question: Under what condition(s) could one say that the interaction between an electron and an electromagnetic wave is not governed anymore by the...
View Articlecomplex form of poisson equation
Hi, I am trying to solve the complex form of poisson equation ∇[ε(x)∇V(x)] = -1/εo ρ(x) with complex permittivity. If I introduce complex permittivity ε = εr - j σ/(εow), then I must introduce a...
View ArticleQuestion About Measuring Specific Heat Capacity
Recently, I did a physics lab experiment to find the specific heat capacity of an unknown sample material. The lab instructions kept insisting that the sample had to be kept in boiling water for at...
View ArticleThermally induced stress
When a bar is heated evenly, and it expands freely, they say it has zero induced stress. How about the stored energy? Isn't some energy stored in the process of expansion? Can this energy be calculated...
View ArticleLighting strikes
I don't know if this is in the right section but here goes any way when lighting strikes does it create a magnetic wave and or an EMP?
View ArticleWhat is Restrahlen effect and Restrahlen band?
I search it on google, books, articles, everyone cite it but noone explain fully what it is. If you can: bibliography please! Thanks a lot!
View ArticleSubmarine Modeling
Hello, I'm working on a project, and my teacher gave me something to think about, but im at a loss. He wants me to come up with an equation to model the maximum height a submarine can go underwater, if...
View ArticleColors of thin layers of materials
Hi everyone. I have the following question: on passivated copper sheets used under high electric fields I found some color patterns I can't really explain. A possible explanation would be that there...
View ArticleConfusion on Newton's 3rd law!!
According to the 3rd law, the equal and opposite forces are acting on two different bodies and therefore cannot cancel each other. They are mutual forces. Why then, so we say the force of gravity on...
View Articlewill, Red, Green and blue lasers wen crossed create the spectrum we crossed ??
hia, if i get red, green and blue lasers, and cross them at one point, and change the intensity of each one accordingly, will at the point of where they cross, display different colours relevant to the...
View ArticleTotal Internal Reflection
When we talk about Snell's law, and total internal reflection in particular, we usually will draw diagrams as if light is coming off a point in a single, straight line (that bends at an interface, of...
View ArticleCoil design and magnet orientation in a unique generator
First, I am not an electrical engineer - I am a hobbyist building a prototype linear-stlye generator based on an idea I had which, for various reasons, cannot be built with magnets that pass completely...
View ArticleLagrangian with friction.
I saw a thread early which said use a like quadratic dissapative force. However I wonderig if for simple situation like on a one day motion that adding an F_r times x term under the potential energy...
View ArticleSpeed of atoms ejected from an oven
My question is this: what is the average speed of atoms released from an oven at some temperature T? For example, in a Stern-Gerlach experiment, hydrogen atoms are emitted from an oven and collimated...
View ArticleFew Fundamental Thermodynamics Questions
Hi I had a few thermodynamics questions on a thread that was locked. The link is here and my questions are directed at the last post. http://www.physicsforums.com/showthread.php?t=225555 Quote:...
View ArticleGood explanation of aeroelastic flutter
After looking into the Tacoma Narrows Bridge collapse, I tried to find out what this thing called aeorelastic flutter is and what causes it. Unfortunately, I didn't get a very good answer for either...
View ArticleSolving inclined plane in different axis.
I can work out the acceleration of a block that will take along the plane when the axes are the ones along and perpendicular to the inclined plane. But, when I choose a horizontal and vertical axis I...
View ArticleIs the energy conserved FOR EACH BODY in a two-body central force problem?
Hi everyone, I would like to know if the energy of each body of a two body gravitationnal problem is separately conserved. I know that the individual angular momentum are separately conserved and that...
View ArticleThermodynamics for a geothermal heat pump
I'm going a bit off the reservation to try something experimental when I attempt my own HVAC installation and I'm having some trouble determining a few things. I want to transfer heat from water...
View ArticleEquality of expectation value integral over coordinate space and over energy
Dear all, I'm wondering, how one could justify mathematically the equality [itex]\int O(E(\vec{x}_1,...\vec{x}_N)) exp(-\beta E(\vec{x}_1,...,\vec{x}_N)) d\vec{x}_1...d\vec{x}_N[/itex] = [itex]\int...
View Article