Lines Definition and 1000 Threads

  1. C

    Magnetic field lines directed?

    Is it possible to direct or confine field lines to be shaped like a laser? I know there are magnets such as neodymium cones that direct field lines through the tip but they don't seem to have the amount of pull as I'm looking for. If there isn't, is there anyway to amplify the power? Maybe align...
  2. nmsurobert

    I Balmer Series Lines: How Do Hot Stars Contain Hydrogen?

    Im reading that very hot stars and very cool stars have weak hydrogen lines. With that being said, how do we know that these very hot stars contain high quantity of hydrogen if we can't see it in the spectra?
  3. S

    LaTeX Underfull \hbox (badness 10000) in paragraph at lines 278--2

    Hi, this error appears ubiquitously in my document, what does it mean and how can I rectify it? Thanks!
  4. shyvir3108

    Comp Sci Read specific lines from a file using fortran90

    Homework Statement I want to read only specific lines from a file using fortran code. Homework Equations Fortran code The Attempt at a Solution I have a dummy.txt file wrote 7 5 6 4 5 6 9 10 14 19 I want read only values between lines 5 to lines10. But when I use print statement, the value...
  5. sergiokapone

    Electric field lines of a sphere in a uniform electric field

    I need to draw electric field lines of sphere in uniform electric field with LaTeX/TikZ. Can anyone show me equation of field lines in polar coordinates?
  6. T

    How do I calculate the capacitance of two unequal lines?

    The capacitance formula for equal line is as follows. : * my question : I want to know the capacitance formula for unequal lines and its solving process . Thanks in advance for any hint.
  7. S

    LaTeX How can I split up a long and complicated equation in LaTeX?

    Hi, how do I split up this horrible equation into several lines? given in latex code: \Psi_2=...
  8. Vivek098

    Magnetic Lines of Dipole and Circular Current wire

    What is the difference between the Magnetic Field Lines of the Dipole and Circular Current Carrying Wire at the centre?
  9. V

    Question on: Smith charts, power and transmission lines

    I would simply like to know: Given a lossless transmission line with a certain characteristic impedance Z terminated in a load L. How can I go about computing the fraction of the time average incident power arriving that is dissipated in the load? Is this possible without knowing the voltage or...
  10. S

    A What is the significance of tilted vortex lines in superconductor vortexes?

    I have read a few parts in various papers where they refer to tiltered vortex lines in superconductor vortexes, however it is not clear what these lines really mean physically. Can anyone suggest a source or a description to this? Thanks
  11. W

    MHB Unlocking An Irrational Location: Solving a Geocaching Puzzle

    This might not be the usual kind of question posted here, but I am trying to solve a geocaching puzzle. The puzzle is called "An Irrational Location", and the only information provided is more or less the following: ~~~~~ No rational person should attempt to visit the posted coordinates Cache...
  12. T

    Why does the solar wind follow magnetic field lines?

    My physics teacher said that the northern lights are the product of charged particles coming from the sun and interactign with our atmosphere. I believe he said that these are deflected by Earth's magnetic field and directed towards the North and South poles. When I look at pictures on this...
  13. C

    Oscillation of a point charge perpendicular to field lines

    Homework Statement Two particles A and B each carry a charge Q and are separated by a fixed distance D. A particle c with charge q and mass m is kept at the midpoint of A and B. If C is displaced perpendicular to AB by a distance x where x<<<D, find the time period of the oscillation of the...
  14. jack action

    What Are the Criteria for Sizing Hydraulic Brake Lines?

    On older GM cars, the brake lines are 3/16" from the front port of the master cylinder, splitting into two 3/16" for each front wheel, and 1/4" from the rear port of the master cylinder, splitting into two 3/16" for each rear wheel. This is the case for drum/drum or disc/drum configurations...
  15. Eclair_de_XII

    Force between two lines of charge?

    Homework Statement "Two very long uniform lines of charge are parallel and are separated by ##x=\frac{3}{10}m##. Each line of charge has charge per unit length ##\lambda = 5.2_{10^{-6}}\frac{C}{m}##. What magnitude of force does one line of charge exert on a ##y=\frac{1}{20} m## section of the...
  16. P

    Calculation of no. of spectral lines for group of similar atoms

    Homework Statement The maximum no of spectral lines for a single atom during it's electron's transition is given by [∆n(∆n+1)]/2 . But I don't seem to arrive at the answer when a group of atoms are present . The question was - What is the maximum number of spectral lines possible for Balmer...
  17. G

    Field lines for masses vs. electrons

    Is there any difference between the field lines you draw when one mass approached another mass and when two electrons approach one another? If there is no difference, does this mean field lines can't be used to predict the forces both particles feel?
  18. G

    Identifying overhead power lines (esp. UK)

    Has anyone got a good link to a guide to UK power lines? I hate looking up and not knowing what's there. For example, my house has several poles leading to it, strung with one live 240V and one neutral, the latter being tapped to Earth at each pole. What if there are two lines, strung...
  19. A

    Draw field lines for both magnetic fields

    Homework Statement Homework Equations N/A The Attempt at a Solution Im not sure if I've done this right because it seems too little for 6 marks. I have arrows coming from the north to the south end for the magnet's magnetic field. I have arrows going counter clockwise around the conductor...
  20. K

    Electric Field Lines: Charge Movement and Conductor/Insulator Interactions

    1. The problem statement "If charges are free to move, the field lines will straighten and shorten as the charges move together" 2. Questions in relation to statement Are there any cases in which charges aren't free to move between two charged objects such as between conductors or insulators...
  21. A

    Understanding Electric Field Lines: An Introduction to E Bar and Tangent Vectors

    Hi, I'm reading the textbook and there is my image. http://imgur.com/a/9BqHm It says "The field vector E bar is tangent to the electric field line at each point". I might want to ask what "tangent" means in this sentence? Sorry to ask that stupid question.
  22. M

    MHB How to Calculate the Distance Between Parallel Lines in Hesse Normal Form?

    Hey! :o Let $ax+by+c=0$ and $a'x+b'y+c'=0$ be the equations of two parallel lines $g$ and $g'$ in Hesse normal form. I want to calculate the between the two lines. We have to pick a point of the line $g'$ and calculate the distance of that point and the line $g$, or not? (Wondering) How can...
  23. A

    Why is del(E_t) zero in TEM mode of transmission lines?

    I was going through MIT opencourseware https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-013-electromagnetics-and-applications-spring-2009/readings/MIT6_013S09_chap07.pdf and I didnt understand exactly why in equation 7.1.37 and 7.1.38 in page 192 the divergence of...
  24. haruspex

    B Counting intersections of lines in a triangle

    As a result of working on https://www.physicsforums.com/threads/area-of-hexagon-geometry-challenge.914759, this question occurred to me: Divide each side of a triangle into n equal lengths. Connect the ends of each length to the opposite vertex with straight lines, thereby forming 3n...
  25. M

    How to combine two lines in one in mechanical sketches

    Would somebody explain how to combine two lines into one? I think this is a CAD question. It's from Ansys's DesignModeler, Geometry Engine. I would like to make lines 1 which is at the right hand side like 2 which is left hand side of the L-shape object. In that program there are options like...
  26. B

    Losses on Power Transmission Lines

    Say a power station transmits 1008 MWh of power per year to a facility however they only receive 900 MWh say the transmission line is 15 km long how would you calculate average power loss per km, now I know that theoretically it will just be 7.2 MWh per km but what calculations would you make to...
  27. P

    B Definition of unshifted spectral lines?

    Hi, N00b question :-) I have read articles about redshift and blueshift and have a good idea about them. What I would like to know is how you decide if something is "unshifted" - what is the definition of this? is there a standardized way of defining/mapping an element's unshifted spectral...
  28. M

    B Graph of lines going through the origin

    Here is an explanation about drawing the graphs of linear lines which, I think, incorrect. So would you check it? "If graph, such as y=7x, goes through the origin, it has only one intercept, and other points will be needed for graphing." I think other points will not be needed because lines...
  29. W

    B Are vertical lines from squinting a Quantum phenomenon?

    When looking at a night light with almost closed eyes, I notice that the light becomes a vertical line. When tilting my head 90 degrees, the line becomes horizontal. Can this be explained by Heisenberg's Uncertainty principle? This question has been asked in another thread : "Squinting at...
  30. M

    Geometry - Arcs created by Secant Lines

    Homework Statement This picture: http://i.imgur.com/n015WjU.png It's drawn with exactly the amount of information from the worksheet. Specifically, the two secants meet at a point, with an angle of 28 degrees between them. Both secants partition off an arc of 120 degrees. The goal is to...
  31. Tania Velarca

    Field lines of a electric charge immersed in two dielectrics

    Homework Statement Hi guys, I hope you can help me with this problem, because I do not have any idea and I could not find anything that could help me, thank you in advance! Draw the electric field lines due to a punctual charge Q immersed in a dielectric medium with constant K1. Q is separated...
  32. G

    Are particles accelerated along magnetic field lines?

    I have a question which puzzled me when I was reading up about auroras. When talking about the interaction of the solar wind and the Earth's magnetic field, the book said that "particles are accelerated along magnetic field lines towards the earth" That didn’t sound quite right, as I was taught...
  33. S

    Transmission lines & reflections

    Homework Statement [/B] Can someone help me solving this problem ? A lossless coaxial cable is used in a data network. it has an er =3 (relative permittivity) It is driven by a pulse source with internal impedance of 10 ohm, 1 V amplitude, square wave with duration of both positive and...
  34. Y

    MHB Analytic Geometry: Lines Problem

    In a triangle ABC: A(-2,7) and C(7,-5). The length of the altitude of AC is 5, and the length of the altitude of BC is the square root of 45. I wish to find the vertex B, given that it is below the line AC. I need your help, I have no idea how to approach this. Thank you in advance. I have...
  35. S

    Solve Transmission Lines Homework: Coaxial Cable, 1kOhm, 10Ohm

    Homework Statement can someone help me solving this problem ? A coaxial cable is driven by a pulse source with internal impedance of 1kohms, 1 V amplitude, square wave with duration of both positive and negative pulse is 800 ns, with negligible rise- and fall-time. The load impedance is 10...
  36. 0

    Intersection of Lines: Solving for m and n to Determine Concurrent Lines

    Homework Statement For which m and n the lines are concurrent? ##r: \begin{cases} x & - & y & = & 1 \\ nx & - & y & - & 2z & + & m & + & 1 & = & 0\end{cases}## ##s: \begin{cases} x & - & nz & + & m & + & n & = & 0 \\ x & + & y & - & 2nz & + & 11 & = & 0 \end{cases}## Solving r gives me...
  37. M

    Drawing constant pressure lines in flow field

    Hi PF! Can someone help me understand how to draw lines of constant pressure in an inviscid flow field, say flow around a cylinder. I am having trouble understanding how to draw these. Any help is greatly appreciated! I ask this question because I am preparing for the Q exam for PhD and one of...
  38. P

    I Fraunhofer Lines: Outdoor Photo Through Bandpass Filter

    If you take an outdoor photo through a bandpass filter that only let's light through in a Fraunhofer line would it be completely dark, like night? Or would it have some daytime illumination?
  39. jedishrfu

    B Fun way of doing multiplication with intersecting lines

    Here's a fun way to do multiplication graphically that originated in Japan:
  40. S

    Two flow lines (pipes) meging into one

    I got two flow lines at 90 degree angle, Line A carrying acid and line B carrying water, each with 1 inch diameter, merging at point P. The third line C beginning at point P, also 1" diameter, should carry 90% water and 10% acid. I came up with option 1 but not sure how to achieve the same using...
  41. C

    Confusion with regards to power lines and the power lost

    Ok, so the title was pretty vague, I'm not sure how to succinctly describe the confusion. Anyway, so I've learned that the power lost is P=I2R, and so by increasing the voltage, as P=VI and is constant, the current will be lowered, and thus the power lost will decrease. I'm confused about a...
  42. C

    MHB Connectors between lines of working

    Hi, please can someone help me understand the right kind of connectors I should use when presenting my work. For example, if I wanted to write down the steps of my working for solving a quadratic I would write this: 9x^2-39x-30=0 3x^2-13x-10=0 (3x+2)(x-5)=0 3x+2=0 or x-5=0 x=-2/3...
  43. S

    A Bar on a fermion field, arrows on fermion lines and particle-antiparticle nature of a fermion

    This question is about the use of bar on a fermionic field in a Lagrangian, the use of arrows on external fermion lines and the particle-antiparticle nature of a fermion. For illustration of my question, I will use the following the charged-current interaction of the Standard model...
  44. B

    I Ave length of intersection of all lines through a unit cube

    I'm having trouble even beginning to figure out how to approach solutions for this. I begin with a unit cube, and imagine all the possible lines that intersect the cube. I am assuming there must be an average length of these intersections; I want to find that average length. Another way to...
  45. S

    MHB Can someone kindly revise these few lines

    I have this Volterra integral equation $X(t)=e^{At}+\int_{0}^{t} \,e^{A(t-\tau)}\epsilon BX(\tau) d\tau$ (1) , of matrix solution $X(t)$ and $X(0)=I$, $A,B\in{R}^{n\times n}$ , $t\in[a,b]$ By iteration: Result 1 : the solution $X(t)$ of (1) can be written as a power series in...
  46. M

    MHB Point (a, b) Reflected About Two Lines

    This question is found in the challenge section of the textbook. This is a two-part question. Like always, I am looking for steps or hints that will allow me to work out the math. 1. If the point (a, b) is reflected in the line y = 3x, show that the coordinates of the reflected points are as...
  47. Andrew Bridges

    Idea for a ball point pen that makes dashed lines

    Ok. So while in my trig class, I had an idea for a ball point pen that, when writing, it has an automatic mechanism for making dashed lines. I mean to say, it lifts the ball point or obscures the path to create a perfect dashed or dotted line, or allows to draw a line of fixed length for...
  48. V

    A photo of the computer screen -- what causes vertical lines

    https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0 https://www.dropbox.com/s/be52pax3jezv3cb/IMG_20170128_170143.jpg?dl=0 I have question what causes vertical lines on the photo of the screen of my laptop? But I would like to find out it alone. Could someone lead me? I know...
  49. FallenApple

    Do charges accelerate because their field lines are changed?

    I ask this because of this diagram. Say that two charges are held a certain distance apart and are let go. Well, we see that the field lines of one charge repels the other. And I noticed that the field lines for an accelerating charge also bends. So can we say that because one field...
  50. karush

    MHB S6.803.12.5.9 are lines parallel?

    $\tiny{s6.803.12.5.9}$ $\textsf{Is the line through $( -4,-6,1)$ and $(-2,0,-3)$ parallel}\\$ $\textsf{to the line through $( 10,18,4)$ and $(5,3,14)$? }\\$ $\textit{presume, convert to vectors first?}$ \begin{align} \displaystyle {}&={}\\ \end{align}
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