Lines Definition and 1000 Threads

  1. G

    Two infinite charged lines -- find the locations where E=0

    Homework Statement A very long (infinite), straight line of charge runs parallel to another very long (infinite) straight line of charge. Both lines are uniformly charged, one with +1*(lambda) and the other with -2*(lambda). The distance between them is d. Find (if any) the location(s) where...
  2. F

    Black body radiation verses spectral lines.

    When objects are heated they produce blackbody radiation which varies with their temperature, and when the electrons in the orbitals of atoms are given energy they produce radiation at specific frequencies known as spectral lines. My question is this. When an object, say a piece of mental is...
  3. K

    Rotate the area bound by the following lines around the x-axis.

    Homework Statement Rotate the area bound by the following lines around the x-axis. y = x^2+1, y = -x^2+2x+5, x = 0, x = 3 Homework Equations None that are uniform enough to put here considering I'm fairly sure it's not washer... The Attempt at a Solution
  4. K

    Why Does Hydrogen Emit a Line Spectrum Instead of a Continuous Spectrum?

    Homework Statement My Chemistry book says: "Before reading further about the details of Bohr's model, speculate as to how they explain the fact that hydrogen gas emits a line spectrum rather than a continuous spectrum." Homework Equations The Rydberg Equation, though I suppose this is more...
  5. H

    Proving Perpendicular Lines in a Quadrilateral

    Homework Statement ABCD is a quadrilateral with AB=CD P,Q,R,S are the midpoints of AD,AC,BD,BC respectively Prove that PS is perpendicular to QR Homework Equations The Attempt at a Solution I've tried a bunch of different avenues, but I think that the most promising one is...
  6. F

    What Are Balanced and Unbalanced Transmission Lines?

    hello forum, I am trying to read and learn about balun. Some transmission lines are said balanced while other unbalanced... In a balanced transmission line the voltage on one wire is always as big as the voltage on the other wire but 180 out of phase. For example wire 1 is at 50 V while...
  7. M

    Find the Proof: Tangent Lines & a Circle w/ Square Root of 3 Radius

    Homework Statement Our teacher was talking about something regarding two tangent lines on a circle who distance between the tangent lines is square root of 3 times the radius of the circle... She wanted us to find the proof of this but I am stumped on where to even look... Does anyone know...
  8. Femme_physics

    Complex numbers - parallel lines meet at infinity ? What does it mean?

    Complex numbers - "parallel lines meet at infinity"? What does it mean? We started learning about complex numbers last week. One of the first things my teacher said was that "We learned that parallel lines never meet. But as it turns out, they meet at infinity." I'm willing to accept it...
  9. I

    Calculating constant field lines

    Hi, I a question related to an equation for a magnetic field vector, B, from a dipole in cylindrical coordinates. This is the equation I found for the B field (thought I'm not 100% certain this is correct). B = (u0*m/4*Pi*r^2)* {2 Cos[theta] , Sin[theta]} where the first index is the...
  10. T

    Drawing equipotential lines and field lines

    Homework Statement Draw the electric field lines and equipotential lines for the electrode configure. Assume one of the parallel plate is at a positive potential and the other one is grounded. Homework Equations The Attempt at a Solution I know the electric field lines and...
  11. L

    T constant lines in Minkowski Conformal Diagram

    Hi, I've been trying to work out exactly why the t=const and r=const lines look like they do in the Minkowski conformal diagram. I started with the usual Minkowski metric in polar coords (t,r) then go into null coords, then pull in the infinities by using arctan transformations, finally I then...
  12. N

    What are these lines? (Picture included)

    We've all seen Carl Sagan's Pale Blue Dot picture, taken by Voyager [PLAIN]http://www.humanistsofutah.org/images/PaleBlueDot.jpg My question is: What are those huge red, green, and orange lines?
  13. Feeble Wonk

    Field Lines in Expanding Space Explained

    Can anyone explain to an ignorant layperson, with as little mathematics/geometry as possible, whether field lines in expanding space become "farther apart". I view this question as being closely related to the concept of quantum foam distribution in expanding space... do virtual point particles...
  14. J

    Electric Field Lines and Equipotential Contours

    Homework Statement The adjacent figure shows the E-field lines (with arrows) and equipotential contours for a certain charge configuration. Determine for each of the following statements whether it is true or false. Assuming that these contours are those of a point charge at the origin...
  15. Femme_physics

    Magnets lines of force are electrons?

    Magnets "lines of force are" electrons? So I understand that a magnetic field is defined by the lines of force that go from the north to the south pole...what are these forces? The flow of electrons back and forth...?
  16. I

    General question about parameterized equations for lines

    I'm supposed to find the equation of a line perpendicular to and intersecting another line. The original line was parameterized in t. I got the answer as L = (0, 1, 2) + s <3/2, -1/2, -1> The book gave it as L = (0, 1 ,2> + t <3, -1, -2> Since both equations describe the same...
  17. C

    Find vector orthogonal to two lines

    Homework Statement L1 pass through the points (-2,36,9) and (-8,44,12) L2 pass through the points (55,-31,7) and (41,-16,13) Find a point P on L1 and a point Q on L2 so that the vector \vec{}PQ is orthgonal to both lines. Homework Equations Dot product/ Cross product The Attempt at a...
  18. I

    Can lines in 3D be parametrized by the same variable?

    For example. L1: x = 11+3t y = 7+t z = 9+2t L2: x=-6+4t y=-2+3t z=-7+5t I was given this problem, and technically these lines don't intersect, right?
  19. P

    Intersection/Collision of two lines in R^3

    Homework Statement Determine whether r1 and r2 collide or intersect: r1(t) = <t^2 + 3 , t + 1 , 6t^-1 > r2(t) = <4t , 2t -2 , t^2 - 7> I am completely lost in this problem and was hoping for a just a hint at where to begin. I'm unsure what it even means if two lines collide or...
  20. H

    How many Tangent lines go to a certain point.

    Homework Statement How many tangent lines to the curve y = x / (x + 1) pass through the point (1,2)? At which points do these tangent lines touch the curve? Homework Equations n/a The Attempt at a Solution I'm completely drawing a blank on this one. Help.
  21. D

    Linear Algebra (distance from two nonparallel lines)

    Find the distance between the nonparallel lines, L1: |x| ...|4| ...|1| |y| = |-1| + t|0| |x| ...|3| ...|2| and L2: |x| ...|1| ...|-3| |y| = |2| + s|1| |x| ...|2| ...|-1| picture the above as matricies, sorry i don't know how to properly make them :...( Attempt at a...
  22. T

    Electric Fields Lines of a pair of Finite Parallel Plates

    Homework Statement Comment on the electric field lines of a pair of finite parallel plates (a) between the plates and (b) near the edges of the plates. Homework Equations The Attempt at a Solution
  23. nukeman

    Spectra: Where do the emission lines come from?

    Im just trying to figure something out here. Iv been working on some spectra stuff. Now, when I look at a gas, I see the spectra, but if I turn up the intesnsity, new lines appear? Where do these lines come from, as I am looking at the same game, just turned up intensity?
  24. S

    Why Are Electric Field Lines Straight Around Relativistic Electrons?

    Imagine an electron in uniform motion moving at a speed near the speed of light. Pictures I've seen of the electric field around such a charge look like this one from wikipedia: The field lines are straight, but clustering around the plane perpendicular to the direction of motion...
  25. H

    Differential geoemtry tangent lines parallel proof

    Homework Statement Prove that a(s) is a straight line if and only if its tangent lines are all parallel. Homework Equations Frenet serret theorem The Attempt at a Solution I'm confused on the direction "if the tangent lines are parallel then a(s) is a straight line". Assume all the...
  26. R

    Finding Electric Field of Charged Ring w/ 2 Lines Intersecting

    I got a question that has a charged ring, with two lines of charge that intersect it. So it looks like a circle with a cross in it. I am asked to give the electric field. Would it just be the sum of each of the electric field from each part? So Etotal= Ering + Eline + Eline
  27. J

    Intersecting & Finding Parallel Lines in R^3 Space

    given two lines x=s(1,2,1) and x=(960)+t(0,1,-1) how would i go about finding a vector that intersects both lines and then finding another line parallel to that vector? help would be much appreciated
  28. N

    Geometry problem. Circle and parallel lines to a circle.

    A circle with diameter 90 is located at (70,100). A given point O is at (0,0). There is a line from O to the circle at point A, line OA. Line BT is parallel to OA at a distance 50 from OA and is a tangent to the circle. How do I find the coordinates A and B? I'm having problems drawing...
  29. L

    Horizontal Tangent Lines: Intersection of Cylinder and Plane

    Homework Statement Consider the plane z = x + 2y and the cylinder x^2 + y^2 = 1 (a) Find a vector function r(t) describing their intersection. (b) Find the points if any where the tangent to ~r is horizontal (c) Find an equation for the tangent line to ~r at each of these points.Homework...
  30. C

    Prof. Walter Lewin's best lines ;)

    If you saw his lectures, you will love it ;)
  31. BobG

    Electrocutions: Downed power lines kill 3; survivors not shocked at all

    Downed power line kills 3 in San Bernardino I wonder if there's a special place in hell for those that make puns at the expense of people dying in a horrible accident.
  32. Y

    Question on TEM mode transmission lines.

    I want to verify the theory of TEM mode tx lines how the signal travel. Please correct me if I am wrong. This mainly refer to stripline, microstrip( assume TEM) etc. 1) The signal is transmited as EM wave through the dielectric between the two lines, not actually current through the...
  33. G

    Equipotential lines for two charges

    Hi there, Could you describe for me what happens to the equipotential lines of two charges as they move close to each other. Thanks
  34. T

    World Lines Problem, axes as meters

    Homework Statement 4) In the above figure, the horizontal axis is x measures in meters, the vertical axis is t measured in meters (SR units!) a) For the pairs of events AB, AC, CB, determine the metric distance between them. b) For each pair answer whether the first member of the pair...
  35. I

    What are the best lines of reasoning for why nothing can travel faster than c

    The argument I've heard following from Special Relativity is as follows: Assume a causal influence can travel faster than c in a given reference frame, and assume it starts at Event A and is the cause of Event B a short time later (Events A and B are also at different points in space). This...
  36. N

    Relation Between Complex Slopes of Perpendicular Lines

    Homework Statement what is the relation between complex slopes of two perpendicular lines?? :think: Homework Equations The Attempt at a Solution i think it is same as the slopes of two st. lines that is the product shud be -1...but the answer given is sum of slopes is 0...
  37. Y

    Calculating Nodal Lines for Water Tapping

    Homework Statement Two students are tapping their foot on the surface of the water in a pool Distance between two point sources : 2m length of the pool : 5m freqency : 1Hz v = 0.6m/s How many nodal lines are created? Homework Equations lambda = v/f d = (n-1/2)lambda The...
  38. T

    Flux and Equipotential Lines of a Harmonic Equation

    Homework Statement I'm not a physics person at all, but I need to solve this Electrostatics problem and I'm stuck. Homework Equations V(x,y)=(2/pi)arctan(\frac{-2iy}{1-x^2-y^2}) The Attempt at a Solution I've derived this equation from a given set of parameters, V(x,y)=1 when...
  39. U

    Vertical Tangent Lines to an Ellipse

    Homework Statement Consider the curve x^2+xy+y^2=27 Homework Equations Find all points on the curve where the lines tangent to the curve are vertical The Attempt at a Solution I found dy/dy = (-2x-y)/x+2y) and I think I found the equations of lines visually to be x=6 and x=-6...
  40. C

    On Skin Effect and Microstrip Lines

    In the field of microwave engineering, skin effect is referred to when people talk about the fact that current, that is, electrons only flows on the surface of transmission lines, e.g. microstrip lines. I've checked many EM books--everywhere skin effect is demonstrated with both E and H...
  41. L

    Reflections in Transmission lines

    Why do reflections occur in transmission lines. Why does the wave travel back from the load?
  42. Z

    Find the angle between the lines

    Homework Statement I have 2 doubts- 1)The equation of the plane containing the line 2x+z-4=0=2y+z and passing through the point (2,1,-1) is? 2)Find the angle between the lines (x-2)/3 = (y+1)/-2, z=2 and (x-1)/1 = (2y+3)/3 = (z+5)/2 The Attempt at a Solution 1)How do I interpret...
  43. H

    What are the uses and limitations of transmission lines?

    "Transmission lines are specialized cables and other media designed to carry alternating current and electromagnetic waves of high frequency (radio frequency or higher), high enough that its wave nature must be taken into account. Transmission lines are used for purposes such as connecting...
  44. C

    B field lines of an infinte solenoid?

    When I have an infinite solenoid , The b field lines point straight up the solenoid and the field is zero outside. But i thought that the field lines have to wrap back around on themselves. Does this not apply in this example . Or am i crazy?
  45. A

    Induced Electric Field Lines When a Magnetic Field Crosses a Plane

    If a time varying magnetic field of infinite dimensions crosses a plane at right angles what can we expect induced electric field lines to look like? Straight lines with direction determined by the right hand rule?
  46. F

    Magnetic Field Lines Formula (3D)

    Curious as to whether there's a formula for calculating the shape of the magnetic field lines, including electro magnets (solenoids). I want to create a 3D graphical display for the magnetic field lines of magnets.
  47. B

    How to Determine the Magnetic Field from Sodium's D Line Splitting?

    Consider the D1 and D2 transitions (3p --> 3s) of the sodium atom (Z = 11). How to calculate the magnetic field experienced by the valence electron arising from its orbital motion, given that the wavelength difference between the D lines? The formula that I have from lecture notes for...
  48. L

    How Transmission Lines Transposition could affect Protection systems?

    I would like to know if Transposition on Transmission Lines could affect the basis and the way the power system is evaluated to set up the protection for the Transmission line? as compared to the non-transposed Transmission Lines. Thanks in advance, Regards,
  49. B

    Find equations of the tangent lines to the curve

    Find equations of the tangent lines to the curve y=(lnx)/x at the points (1,0) and (e,1/e) . Illustrate by graphing the curve and its tangent lines. i found that the derivative is 1-lnx/x^2 what do i do next? thanks
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