Rules Definition and 516 Threads

Pls point out me every body. I wish to know why does the magnetic field and current are perpendicular to each other? Or is it natural phenomena?

This is not a homework problem, but advice on the presented examples would be helpful anyways. Does anyone know of a good QM textbook or website that discusses the rules for applying derivatives in QM? In reviewing many of the derivations, I find many weird applications with no reasoning from...

Homework Statement http://www.cramster.com/Answer-Board/Image/20073231626286331026398833900007956.jpg This is not problem. I just having trouble understanding the basics. Please just tell me right away, don't 'assist!' I trying to understand the right hand rule. Here are to...

Homework Statement Determine the current in each branch of the circuit shown in Figure P28.19 (attached) Homework Equations Kirchoff's Rules: \Sigma I_{in} = \Sigma I_{out} \Sigma \Delta V = 0 The Attempt at a Solution I have no idea where to begin. It's in the Kirchoff's...

in peskin-schroeder and http://www.hep.phy.cam.ac.uk/batley/particles/handout_04.pdf" the amplitude for e^-e^+\rightarrow \mu^- \mu^+ is written using feynman rules as follows -iM=[\bar{v}(p_2)(-ie\gamma^\mu )u(p_1)] \frac{-ig_{\mu\nu}}{q^2}[\bar{u}(k_1)(-ie\gamma^\nu )v(k_2)] but what...

Homework Statement Find the eq. constant for the reaction CH3COOH (aq) + NO2- (aq) = CH3COO- (aq) + HNO2 (aq) The Attempt at a Solution I find Ka for the reaction CH3COOH = CH3COO- + H+ and Kb for the reaction NO2- + H+ = HNO2 But what are the rules then? I try multiplying the...

not totally sure this should be in the advanced physics section. its a general test your knowledge question of everything youve learnt, so naturally i can't remember anything... a magnet of magnetic moment U is droped such that it falls down metal tube of length L. the magnet's magnetic...

I was playing checkers today with a friend and the weirdest thing happened. I was black and he was red. I had a black piece situated so that there were no possible moves for his red piece, but i could still make a move. It eventually came down to him having two pieces (one that couldn't move and...

Homework Statement Solve (e^(x^2))` , use this result to solve §5x*e^(x^2)dx Homework Equations * is multiply ` is derive 1.§e^xdx=e^x+C 2.§e^kxdx=1/k*e^kx+C 3.§a^xdx=1/ina*a^x+C (a is a number) 4.§k*f(x)dx=k*§f(x)dx The Attempt at a Solution (I'm alittle confused as to...

Kirchoff's Rules I can not find a good explanation anywhere for Kirchoff's rules. Googling onlygives me links that don't explain it well, and my textbook's explanation is lacking as well. I'll go over my textbook's description, so hopefully someone here can clarify this for me. 1...

Homework Statement Find the currents in the circuit shown in the figure attached. Homework Equations I actually have the solution worked out but I don't understand why something was done. So they chose to travel the bottom loop and the top loop clockwise in both cases. So they set up the...

Homework Statement http://img245.imageshack.us/my.php?image=physicsef4.jpg Homework Equations The change in Voltage = 0. The Attempt at a Solution Ok I have no clue where the loops go from. I want to say something like the current for I1 starts at the 10V battery in the middle...

[SOLVED] Using Kirchoff's Rules Homework Statement http://img266.imageshack.us/img266/4120/kirchoffho1.gif In the circuit, I_1 = 1.6 A. Find the value of: (a) the current I_2 and (b) the current I_4. Homework Equations Junction Rule, Loop Rule, V=IR The Attempt at a Solution Small loop...

A triangular array of resistors is shown in the figure. What current will this array draw from a 35.0 V battery having negligible internal resistance if we connect it across (a) ab, (b) bc, (c) ac? Kinda confused... just anything to start me off on the right track would be very helpful.

After a prolonged dispute that progressed through US District Court and the 11th Circuit Court all the way to the US Supreme Court, the Supreme Court finally settles whether Webster’s Dictionary’s definition of “any” should take precedence over ejusdem generis and noscitur a sociis...

I am asking this question because I did not get it clarified in any of the books I have read. What is the rule for having the quark structure of an antiparticle given the structure of the particle?Is it always OK to put bar on the quark symbols of the corresponding particle? Specifically,I...

hello I got al little bit confused about spins flipping in an EPR experiment. As far as I know, the idea of EPR is to measure the absorption of an electromagnetic wave induced by spin flips if the energy is conserved by \hbar \omega = g_{spin} \mu_B B_0. But now I heard several times that a...

[SOLVED] feynman rules Hi , It is a simple question from the book of david j .griffiths :"introduction to elementary particles" (6.11) Homework Statement (a) Is A--->B+B a possible process in the ABC theory (feynman rules for a toy theory) (b)Suppose a diagram has nA external A lines , nB...

Simple math rules seem contradictory... :( Consider this simple expression: x^8 - 16 If we wanted to write this expression as the product of two factors, we could start with something simple like this: \sqrt{x^8 -16} . \sqrt{x^8 -16} From that, we would simply get this: (x^4 -...

Homework Statement For \Deltal = 0 the transition rate can be obtained by evaluating the electric dipole matrix elements given by \vec{I} = \int \Psi^{*}_{1,0,0} (e \vec{r}) \Psi_{2,0,0} d\tau Homework Equations The Attempt at a Solution I've got the two wave functions...

Homework Statement What is the wavelength of the lowest note that can resonate within an air column 42 cm in length and closed at both ends. Homework Equations Given: l = 42 cm n = 1 Required: \lambda Analysis: l = \frac{n\lambda}{2} therefore \lambda = \frac{2l}{n}...

I am wondering whether someone can suggest a good ref or two (preferrably with worked example) on how to use Cutkosky (or whatever it is called) cutting rules in QFT to help pick out the absorptive/Imaginary part of a 1- or 2-loops diagrams. I have already tried Peskin and Schroeder, which is...

I am wondering whether someone can suggest a good ref or two (preferrably with worked example) on how to use Cutkosky (or whatever it is called) cutting rules in OFT to help pick out the absorptive part of a 1- or 2-loops diagram. I have already tried Peskin and Schroder, which is good only up...

Homework Statement The currents are flowing in the direction indicated by the arrows. A negative current denotes flow opposite to the direction of the arrow. Assume the batteries have zero internal resistance. http://img123.imageshack.us/img123/2045/599c898aa10950d7027807dyc7.th.jpg...

Should you apply the rules of significant figures when you are doing any kind of physics, chemistry, or mathematics computation? Like, for example if you are doing homework problems in your textbook, should you still follow the sig fig rules or should you only apply them in labs and measurements?

I'm quite confuse with some concepts here. The selection rules are derived from the requirements that quantum numbers must be conserved. It's OK. Then I see they give rules for so-called electric dipole transitions. I just wonder why dipole comes in here. How do you classify these kinds of...

Before posting anything, please review the https://www.physicsforums.com/showthread.php?t=414380". If you are seeking help with a homework/coursework/textbook-related issue please post your problem in the appropriate forum in our https://www.physicsforums.com/forumdisplay.php?f=152" area. All...

Can you give us the transition rules regarding four quantum no.s?

Homework Statement This is the circuit I'm working on: Homework Equations My equations are: 4.64v=-200I1-800I3 4.64v=750I3+800I2 4.64v=-200I1-750I3The Attempt at a Solution I should have a third unknown in each equation. I not seeing where I'm going wrong. I'm supposed to put this in a 3X3...

Who's watching the playoffs? Who are you rooting for? My Bulls are exciting again, so after many years of not caring about the NBA, my interest is piqued again. It's been so long since I've paid attention to the playoffs (I started watching again last year), that it seems there must have been...

Homework Statement There seem to be three right hand rules for dealing with magnetic field, current, and force, and I don't quite understand how to use them. Namely, I'm having trouble understanding why two parallel wires with current flowing in each of them attract if the currents are in...

Homework Statement using kirchhoff's rules, determine the current through and voltage drop across each resistor in the accompanying figure. Homework Equations V=IR, potential voltage ( voltage drop )= current * resistance Voltage in series Vt=V1 + V2 + V3... Current in series...

Homework Statement Apply kirchhoffs rules to find the currents in the circuit shown http://img297.imageshack.us/img297/5048/kirchvm8.jpg Homework Equations here's what the book says i3(25 ohms) = 12 V i2(15 ohms) = 6.0V + 12 V i1 = i2 + i3 The Attempt at a Solution i...

At last a guy has taken the time to write this all down Finally, the guys' side of the story. (I must admit, it's pretty good.) We always hear " the rules" From the female side. Now here are the rules from the male side. These are our rules! Men are NOT mind readers. Learn to...

I have a question about applying the rules of significant figures to calculations. Should one apply the rules to everyday calculations? I don't know if it will benefit me in the long run to count the number of sig/decimal places in numbers in the simplest calculations. If I major in...

Homework Statement Use Kirchoff's rules to determine I1, I2 and I3 for the following circuit: https://chip.physics.purdue.edu/protected/Prelab221img/e4pp2.jpg E1 = emf = 9 V r = internal resistance = 1.5 ohms R1 = 5 ohms R2 = 15 ohms R3 = 22.75 ohms Find I1, I2, I3 Homework...

Hi. We havnt started limits in class yet, but I've come across one, which i need to evaluate. \mathop {\lim }\limits_{n \to \infty } 2\pi r + 2nR\sin \frac{\pi }{n} For a limit like that, can i just substitute infinity into the equation? Or is there some rule against that? If so...

Homework Statement To find the current traveling through a circuit with parallel and series connections. The circuit looks something like this. *Right now my webserver is giving me fits and won't let me login. I will try and get a picture to those who cannot understand what I am about to...

Homework Statement Use rules of inference to show that if \forall\,x\,(P(x)\,\vee\,Q(x)) and \forall\,x\,((\neg\,P(x)\,\wedge\,Q(x))\,\longrightarrow\,R(x)) are true, then \forall\,x\,(\neg\,R(x)\,\longrightarrow\,P(x)) is true. Homework Equations Universal instantiation, Disjunctive...

A particle traveling through space will (at least according to Newton's first law) continue at the same velocity etc. etc. My question is this: how does this particle "know" that this is how it must behave and that it is behaving correctly? Either the rules of the universe are contained...

Hey everyone. Just a quick high school physics question about determining magnetic fields using Hand rules. The only thing I have trouble trying to understand is how to determine the way a compass arrow will point if you place it on top, or under an electric circuit. I know that they are...

I've been given a small project to ease me into life as a PhD student and part of it involves working out Feynman rules for scalar bosons coupling to gauge bosons. I've been reading through Peskin and Schroder Chapter 9 and want to clarify if I've got my understanding right of how to do it...

Two hockey pucks, labeled A and B, are initially at rest on a smooth ice surface and are separated by a distance of 18.0 . Simultaneously, each puck is given a quick push and they begin to slide directly toward each other. Puck A moves with a speed of = 2.70 , and puck B moves with a speed of...

Can someone give me a hint on how to prove that exp[A+B]=exp[A]exp[B]exp[-c/2] where A and B are two operators such that [A,B]=c, where c is a complex number. This is not homework or something, I'm just curious when reading the rules.

Hey I’ve now come across integration in my maths course for my first time. I was wondering if somebody out there might be able to help me with a couple issues regrading this topic. Firstly I would appreciate if I could be told all the necessary rules for all calculations regarding integration...

Now that the World Cup is finished - we can turn our attention to more important matters. :biggrin: http://www.usfooty.com/usfooty/ - In US. http://nyfooty.com/ http://afl.com.au/ - In Aus http://en.wikipedia.org/wiki/Australian_rules_football Of course, the best is Victorian...

http://news.yahoo.com/s/ap/20060629/ap_on_go_su_co/scotus_guantanamo_trials_4;_ylt=AnAA3ePu334f9K110LZV6yg3NiUi;_ylu=X3oDMTBiMW04NW9mBHNlYwMlJVRPUCUl http://news.yahoo.com/fc/world/guantanamo_detainees It's about time. Imagine that - this president doing something illegal! Who'd've...

I have only one question at the moment which I am pondering over. Now I am aware the the Laws of Physics govern most happening in the Cosmos, but what made these laws? I mean how did the speed of light end up at 3*10^8, How did gravity come about, what started time and when/how and what did the...

This is a problem from my physics book. We are learning Kirchhoff's rules with electric circuits and I'm at a loss at what to do here. I apply them just fine to a three loop circuit, using some algebra: |-/\/\-|\//\ -| | | |--|\--/\/\/--| | |...

About bloody time! http://sport.guardian.co.uk/boxing/story/0,,1773594,00.html