Cross-section Definition and 76 Threads

  1. R

    How Do You Calculate the Inductance of a Toroid of Circular Cross-section?

    Homework Statement A toroid of circular cross-section of radius a and mean radius r_{m}. Show that the inductance of this coil is given by L = μ_{r}μ_{o}N^{2}[r_{m}-(r_{m}^2-a^{2})^{1/2}]. Homework Equations The B-field of a toroid: B = μNI/2πr (phi-direction)The Attempt at a Solution Total...
  2. V

    How can I normalize a plot by the cross-section in particle physics?

    Just a quick question--long story short, I need to normalise a plot by the cross-section, but I'm not sure how to do that and the Google hasn't been too helpful. I was thinking about scaling it by the cross-section times the luminosity--does this sound reasonable?
  3. E

    Calculating period and cross-section of a beat pattern surface.

    Homework Statement Beat pattern is superposition of two sine functions with a little frequency difference. (http://en.wikipedia.org/wiki/Beat_(acoustics)#Mathematics_and_physics_of_beat_tones) We use this pattern to generate a surface, by adding another beat pattern with 60 degrees...
  4. S

    Can Motor Coil Cross-Section Equations Determine Torque and RPM?

    Are there any coil-cross sections equations?
  5. V

    MCB characteristics and specification of conductor cross-section

    [PLAIN]http://www.buildingtechnologies.siemens.com/bt/low-voltage/EN/news_installation-technology_installationstechnik/new_products/BETA/PublishingImages/5SL_Leitungsschutzschalter_Miniature-Circuit-Breakers.jpg Miniature circuit breaker (MCB) time-current characteristic has two specific...
  6. S

    What is the meaning of 'kappa' in Parcs cross-section input files?

    Background: For a BWR-transient calculation I'm trying to convert cross-sections I got from PSG2/Serpent simulations in Parcs [CrossSection] Input files. My Question: Parcs makes use of SNF Nu-fission cross section SKF Kappa-fission cross section I assume this means Nu (as in...
  7. P

    Determine location of structural break in cross-section data

    I'm trying to run a simple regression for a data set (n=165). I've determined via a Chow Test that there exists a structural break somewhere; the same least squares estimate cannot be accurately used to represent the entire range of values the explanatory variable takes on. I've found two very...
  8. H

    Differential cross-section and scattering.

    Homework Statement A beam of 0.38 MeV neutrons is incident on a 113Cd foil of thickness 1mm. The absorption 48 cross-section for 0.38 MeV neutrons is 5 barns. What is the fraction of neutrons absorbed by the foil...
  9. Z

    Volume by cross-section: ellipse and equilateral triangle cross sections?

    Volume by cross-section: ellipse and equilateral triangle cross sections?? Homework Statement The base of a solid is the region bounded by the ellipse 4x^2+9y^2=36. Find the volume of the solid given that cross sections perpendicular to the x-axis are: a) equilateral triangles b) squares...
  10. Z

    Volume of solid by cross-section question?

    Homework Statement I need to find the region bounded by these curves then find the volume of the solid generated by revolving this region about the x-axis. y= cscx, x= 1/4pi, x = 3/4pi, y=0 Homework Equations The Attempt at a Solution So I managed to sketch this region.. but I have trouble...
  11. S

    What Fraction of a Water Molecule's Mass is Hydrogen?

    Hi, see attachment for questions/equations and my attempt. I have had a go at this question but cannot get the correct answer, could someone be kind enough to point out my mistake and point me in the right direction. Cheers (sorry for poor pic quality)
  12. C

    Volume by parallel cross-section.

    The questions: the base of a solid is the region bounded y=x^2 and y=4. Find the volume of the solid given that the cross sections perpendicular to the x-axis are squares. The answer is 512/15. I set A(x)= (2y)^2 = 4(x^2)^2=4x^4, and the answer is wrong when I integrate this from x = -2 to x =...
  13. E

    Find the volume of a solid with given cross-section

    Homework Statement The base of a solid is a circle of radius 4. Find the volume of the solid if each cross-section perpendicular to a fixed diameter of the circle is an isosceles triangle with height equal to its base. Homework Equations Volume of an object with given cross-section...
  14. V

    Calculating resistance from cross-section

    Homework Statement http://www.vkgfx.com/physics/p5.gif Homework Equations R = rho*l/A The Attempt at a Solution Initially I thought this would be easy. I could just write the surface area A of the trapezoid by its geometric area formula and multiply it by h. I thought about it though...
  15. A

    Differential Cross-Section: What is it and Why Does it Matter?

    Can someone *please* explain what a "differential (scattering) cross-section" is? I've tried and tried and tried to wrap my head around what this really is, and to develop some physical intuition about it, but I just can't do it. Can someone please explain what the "differential cross-section,"...
  16. O

    Scattering Cross-section Problems in Shankar 19.3.2 and 19.3.3?

    Homework Statement Problems are Shankar 19.3.2 and 19.3.3 with spherically symmetric potentials V(r)=-V_{0}(r_{0}-r)\theta and V(r)=V_{0}exp(-r_{2}/r^{0}_{2}^{}) Homework Equations f\left( \theta \right) = - \frac{{2\mu }}{{\hbar ^2 }}\int\limits_{r_0 }^r {\frac{{\sin qr'}}{q}V\left(...
  17. H

    Maximizing Area of Cross-Section of Isosceles Trapezoid

    Homework Statement attached. It is just part a i am attempting for now. Homework Equations area of trapezoid = h(b1+b2 / 2) where h is height, b1 is base one and b2 is base two. The Attempt at a Solution i really tried, i didn't know where to start. the answer i got was 30cm for base...
  18. N

    Macroscopic Absorption Cross-Section

    The compositions of nuclear reactors are often stated in volume fractions. i.e the fractions of the volume of some region that are composed of particular materials. Show that the macroscopic cross section for the equivalent homogeneous mixture of materials is given by ∑a = f1 ∑a1 + f2∑a2 +...
  19. L

    Differential cross-section divergence

    Hello, I was wondering if anyone could explain the troubling divergence here of the differential cross-section for rutherford scattering for \theta = 0. I know it must have something to do with the fact that the em force extends to infinity, which makes sense to me for the total cross section...
  20. K

    Cylindrical shell and cross-section volume concept question

    When a problem with a number of equations is given, asking to find its volume, a student has a choice between the cylindrical shell method and the cross-section method. However, regardless of what method is chosen, do both answers end up being EXACTLY the same?
  21. J

    Photoelectic cross-section question

    Homework Statement Show that if we consider photoemission from the 1s state of a charge Z atom, \sigma \propto Z^5}} , in the limit p_fa_0/Z\hbar >> 1. Homework Equations \sigma = \frac{128a_0^3\pi e^2p_f^3}{3m\hbar^3\omegac[1+p_f^2a_0^2/\hbar^2]^4}} The Attempt at a Solution Actually...
  22. D

    Why Does GEANT4 Calculate a Lower Ionization Cross-Section Than Expected?

    Hi. I need to calculate the ionization cross section in the accelerator storage ring. In all science works i read, that this parameter is over 2 Mbarn. I use the GEANT4's formula for cross section and got the cross section is ~milibarn. Please help me to calculate this cross-section. you can...
  23. O

    Weak interaction cross-section

    Homework Statement Cross-sections for weak interactions at an energy E increase with E as E^2. Show that the rate of weak interactions in the early universe depends on the temperature T as \sigma_{wk} \propto T^52. The attempt at a solution The only formula I can find is \sigma_{wk} = g_{wk}^2...
  24. D

    Ionization cross-section energy dependency?

    Alright, so I'm looking into electron-impact ionization of Argon, and subsequently the collision ionization cross-section. While i have found articles that experimentally find these cross sections at different energies (energies of the electrons that is), such as here...
  25. S

    Explaining Cross-Section, Diff. Cross-Section, & Solid Angle

    well I can follow the math and derive the things I'm about to ask about and do problems asked of me but I'm kinda missing something, I guess Can someone just give me a fairly layman's explanation of: cross-section, differential cross-section, and a solid angle? Those are all things I thought...
  26. F

    Exclusion plots and cross-section?

    Hello everyone, As I've mentioned in a thread in the cosmology forum, I'm currently reseraching dark matter. I am often confronted with 'exclusion plots' for the results of WIMP direct detection (via nuclear recoil) experiments, where one axis depicts WIMP mass, and the other depicts cross...
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