What is Arc: Definition and 485 Discussions

An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The current through a normally nonconductive medium such as air produces a plasma; the plasma may produce visible light. An arc discharge is characterized by a lower voltage than a glow discharge and relies on thermionic emission of electrons from the electrodes supporting the arc. An archaic term is voltaic arc, as used in the phrase "voltaic arc lamp".
Techniques for arc suppression can be used to reduce the duration or likelihood of arc formation.
In the late 1800s, electric arc lighting was in wide use for public lighting.
Some low-pressure electric arcs are used in many applications. For example, fluorescent tubes, mercury, sodium, and metal-halide lamps are used for lighting; xenon arc lamps have been used for movie projectors. Electric arcs can be utilized for manufacturing processes, such as electric arc welding and electric arc furnaces for steel recycling.

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  1. J

    Faraday Cage and a high voltage discharge arc

    In the following video: I understand how the Faraday Cage works, but what has me confused is the arching. If charge is building up on the sphere and then arching over to the cage, where then is that charge sunk to? You would think it would stop arching when there was sufficient charge on the...
  2. Z

    How to Draw an Arc Starting at a Specific Point

    Homework Statement Hi, I am trying to draw an arc at the top of two parallel lines i.e connecting two coordinate (130, 170) & (230, 170) using the function below. I can't understand how to start the arc at a particular point. public abstract void fillArc(int x, int y...
  3. T

    Did i calculate the V/A/R of a plasma arc properly?

    Hello there! So i am currently sitting in my EME class and have nothing to do, so i decided to try spit-balling the V/A/R of the plasma arc my Tesla Lighter produces. note that i did not physically take it apart, and my goal was just to get a rough estimate for the arc itself or at least get a...
  4. J

    Net electric field of a charged arc

    Homework Statement So this was a problem worked in class by the professor in class. Find the net electric field at the origin due to the arcs Homework Equations L=2πr/4 λ=q/L E=kQ/r2 The Attempt at a Solution So the professor gave the answer using the fromula...
  5. S

    Finding length of an arc produced by projectile

    So I decided to try deriving a general formula for fun. Being a high school student, the calculus got scary very fast. At this point, I'm just curious as to what the best approach to this might be. The approach I used was finding y as a function of x and then inputting it into the arc length...
  6. K

    Finding the Center and Radius of a Circle with Complex Numbers and Loci

    Homework Statement Sketch the loci, find centre point and the radius of the circle. args((z-3i)/((z+4))=π/6[/B] Homework Equations args(x/y)=args(x)-args(y) Circle theorem - inclined angle theoremThe Attempt at a Solution I sketched the circle with major arc. Radius= using Pythagorus I got...
  7. F

    MHB Arc length & similar questions

    Hello! I really don't understand this concept, and I have an example problem that I am working on that I just CANNOT figure out! Any help? Thanks so much in advance! A group of people get on a pirate ship ride at the fair. This ride is a swinging pendulum with a maximum swing angle of 65 degrees...
  8. bananabandana

    General proof of Arc Length For Parametrised Coodrdinates

    Homework Statement Prove that, given a metric ##g_{ij}## such that ##ds^{2}=g_{ij}dx^{i}dx^{j}##, where ##x^{r} = x^{r}(\lambda)## , we have the following result for the arc length: $$ L(p,q) = \int_{p}^{q} ds = \sqrt{ g_{ij} \frac{dx^{i}}{d \lambda} \frac{ dx^{j}}{d \lambda} } d \lambda $$...
  9. B

    Maximum uniform speed on a arc of a circular path ?

    Question :- A car has to move on a path, that is a arc of a circle of radius (##R##). The length of the path is (##L##). Suppose it starts on the highest point of the path, find the highest uniform speed for which, it does not lose contact with the path on any point ? My attempt :- I made a...
  10. H

    I Prove centre of mass of an arc is rotationally invariant

    Suppose the coordinates ##(\bar{x}, \bar{y})## of the centroid (or the centre of mass) of an arc is defined as follows ##\bar{x}=\frac{1}{L}\int x\,ds## and ##\bar{y}=\frac{1}{L}\int y\,ds##, where ##L## is the arc length. Could you prove that the centroid is invariant under a rotation of...
  11. J

    I Decomposing the arc length of a circular arc segment

    A particle travels along a circular arc segment centered at the origin of the Cartesian plane with radius R, a start angle θ1 and an end angle θ2 (with θ2 ≥ θ1 and Δθ = θ2 - θ2 ≤ 2π). The total distance traveled is equal to the arc length of the segment: L = R(Δθ). I would like to find the...
  12. A

    Challenge problem -- rock sliding up and over a roof into an arc....

    Homework Statement One side of the roof of a house slopes up at 37.0°. A roofer kicks a round, flat rock that has been thrown onto the roof by a neighborhood child. The rock slides straight up the incline with an initial speed of 15.0 m/s. The coefficient of kinetic friction between the rock...
  13. K

    Does electrical arc with the same power have same temp?

    Does electrical arc with the same power but different voltage and current have same temperature? When electrical arc is form, it is estimate that the temperature is about 3000K Does temperature depend on voltage or current alone? Or does it depend on power(P=VA)? I think it is power, because...
  14. LLT71

    B Why don't we use arc length formula to calculate wavelength?

    can you please explain me why don't we use arc length formula to calculate wavelength? seems a bit confusing...
  15. G

    Arc length in polar coordinates

    I know that an arc length in polar coordinates can be computed by integrating $$\int ds$$ using the formula ##ds=\sqrt{\rho^2 + \frac{dr}{d\theta}^2}d\theta##. But, seeing that ##s=\rho\theta## and ##ds = \rho d\theta##, why is it wrong to calculate arc lengths with this expression for ##ds##?
  16. K

    Electric arc in 0 gravity? Curved or straight?

    I observe that electric arc forms a curve. I think that this is because electric arc is extremely hot and hot air goes up because it has less density. So if electric arc occur at 0 gravity would it be straight? from wikipedia https://en.wikipedia.org/wiki/Electric_arc Thank you.
  17. 24forChromium

    Area of a sector is the integral of arc length?

    Area_sector = 0.5 (radius)^2 * angle Arc length= radius * angle Can it be said and proven that the area of a sector is the integral of the arc length? What would that even mean?
  18. G

    MHB Yes, your solution is correct!

    Consider the segment of the curve $y = \cosh(ax)/a$ between $x = −l$ and $l$. Here $a$ and $l$ are positive constants. Find an explicit expression for the length of this curve segment in terms of $a$ and $l$, as well as its limit for $a \to 0$. What I had done: Using the formula $\displaystyle...
  19. Colin LeMahieu

    Modeling plasma instability with electric arc discharges

    I was reading a paper recently about guiding electric arc discharges with lasers. http://loa.ensta-paristech.fr/ilm/uploads/ILM/134_Forestier_discharge_AIPAdvances_2_012151_2012.pdf Since electric arcs are plasmas and they seem to be stabilized by lasers, could the same principle be applied to...
  20. Aero_Arnendu

    How near we are to make a Real Iron Man's Arc Reactor?

    Hi , I, Arnendu, want a really big fan of Iron Man and Physics. I have a question . We all know iron man get his suit's power from The Arc Reactor. So, I think why scientists can't make it properly, the science behind it and its usefulness. So, I request you all to send your reply...
  21. NicolasPan

    Comp Sci Error while calculating arc length of curve in Fortran

    The program must calculate the length of the curve of ƒ=3.1*x^2-5.3/x between x=1/2 and x=3/2.The legth should be calculated as the sum of n line segments starting with n=1 and ending with n=20. I really can't find why the result I'm getting is wrong.Thanks in advance I am giving you the code...
  22. RelativeJosef

    Finding the radius of a Proton's arc inside a square.

    Homework Statement This is for a practice question on an exam: I am able to finish the problem, if I could figure out how to find the radius of this arc the proton makes. Homework Equations I have nothing. The Attempt at a Solution I have tried arc length equations and just integrating the...
  23. adi adi

    Arc Length Circle Quadrant 1: Solve ∫√(1+(dy/dx)2)dx

    Homework Statement find the arc length of a circle in the first quadrant with an equation x2 + y2 = a2 Homework Equations arc length = ∫ √(1 + (dy/dx)2) dx The Attempt at a Solution i got stuck on how to solve the integral
  24. P

    What is the B-field at the center of a semicircle using the Biot-Savart Law?

    Homework Statement Use the Biot-Savart Law to find the magnetic field strength at the center of the semicircle in fig 35.53 Homework Equations Bcurrent=(μ/4π)*(IΔsXr^)/r2 Bwire=μI/2πd The Attempt at a Solution The solution from the back of the book is B=μI/4πd It looks like they just added...
  25. M

    MHB Exploring Arc Lengths and Curves

    Hey! :o In some notes that I am reading there is the following: $$(\delta s)^2=(\delta x)^2+(\delta y)^2 \Rightarrow \left (\frac{\delta s}{\delta x}\right )^2=1+\left (\frac{\delta y}{\delta x}\right )^2$$ When $\delta x \rightarrow 0 $ we get $$(s'(x))^2=1+(y'(x))^2 \Rightarrow...
  26. Dembadon

    Antiquated Switchgear: Arc Flash Hazards

    I am reviewing the LV and MV switchgear and their protection path within our plant. A significant number of critical breakers and enclosures are 20-30 years old and are in need of replacement. In addition to considering the operational advantages of upgrading the gear, I am trying to find...
  27. Dethrone

    MHB Arc Length Formula: Understanding the Proof

    I'm reading about Line Integrals, so I thought I'd review the proof for the arc length formula. However, there's something I don't quite understand about the proof that I either overlooked or understood before. From what I see, the arc length formula holds because the MVT guarantees that there...
  28. R

    Arc Length. Simplify expression

    Homework Statement I'm trying to find Arc Length of F(x) = (e^x + e^-x)/2 0< x < 2]Homework Equations L = integrate sqrt ( 1 + (dy/dx))^2)The Attempt at a Solution (dy/dx)^2 + 1 = 1/4e^2x + 1/4e^-2x + 1/2] I don't know how to take the square root of the above function so I can be able...
  29. Joshua McAnaney

    An Observation And A Question -- Why does metal arc in a microwave oven?

    So, I'm new around here and I'm not entirely sure if this is in the right section, but today I noticed something which I found thought-provoking. Before I go into this, I should point out that I'm 16, so all of my physics knowledge above high-school level is entirely self-taught, so I still have...
  30. JJBladester

    Possible grounding issue - HDMI over CAT-6 electrical arc

    I was recently asked to help with some A/V stuff at my church. The goal was simple: Display HDMI video from a laptop to two LCD TVs. Since distance was an issue, I purchased an active HDMI-to-Ethernet converter. I've included a diagram for reference. When I went to plug the 3' HDMI cable...
  31. Padrepapp

    Coupling Xe Arc Lamp into Fiber Bundle

    Hey, we are trying to couple the light of a 75 W Xe Arc Lamp (Hamamatsu L2194) into a 800um(0,8mm) diameter fiber bundle (7 fibers). Now we have 2 plano convex lenses (25mm diameter, 30mm EFL, edmund serial #45-364), the first for collimating the second for focusing onto the fiber. We are...
  32. Vinay080

    Is the Length of an Arc Equal to its Straight Line Distance?

    Premise 1: Line is composed of points. Premise 2: Each point is associated with specific co-ordinates (x,y). Premise 3: Lines of equal length have equal number of points. Lines of greater length have greater number of points. Premise 4: Each value of x in the function f(x) gives a single...
  33. D

    Launch Ball Highest: Velocity Lost in Arc

    Homework Statement We're assigned to build a ramp that launches our ball as high as possible. For now we're not taking any friction into account. Max height: 120cm Image: http://i.imgur.com/4DmX0mZ.png Homework Equations v = g * t Ep = m x* g * h Ek = (1/2) * m * v^2 The Attempt at a...
  34. J

    What is the theory behind DC arc fault detection for PV systems?

    Hello, I am wondering where a good article may be discussing the theory behind DC arc fault detection for PV systems. Seems most articles are based on detection for AC circuits. Trying to have a better understanding for troubleshooting purposes.
  35. A

    MHB Calculating the length of an arc inside a circle

    A sad and strange image, I know, but better than none at all. What you see is a stake I'm trying to model using CAD software. With the dimension given (5 inches--in case it's not clear, the distance from the top of the equilateral triangle that encloses this shape to the midpoint of the red arc)...
  36. P

    Finding Arc Length of a Curve: Using ##dx## and ##dy##

    The arc length of any curve defined by ##y = f(x)## is found as follows: $$ds = \sqrt{dx^2 + dy^2}$$ $$ds = \sqrt{dx^2(1 + {\frac{dy}{dx}}^2)}$$ $$ds = \sqrt{dx^2} \sqrt{1 + [f'(x)]^2}$$ $$ds = \sqrt{1 + [f'(x)]^2} dx$$ Isn't ##\sqrt{dx^2}## equal to ##|dx|##, and not ##dx##?
  37. W

    Area/2nd Moment of Inertia of an arc/ring

    Homework Statement I'm trying to solve for the area moment of inertia of a curved arc. To visualize this, it would be like a bent piece of cardboard (two arcs with two lines connecting them at their end points). I'm modelling the differences in area MOI with an increasingly curved piece of...
  38. Albert1

    MHB Find Length of Arc EF in Triangle ABC

    $\triangle ABC$,with $\angle A=70^o,$point $O$ is the midpoint of segment $\overline{BC}=12$ circle $O$(wth center $O$ and radius $\overline{BO})$, meets with $\overline{AB},\overline{AC}$ at points $E$ and $F$ respectively please find the length of arc $EF$
  39. RJLiberator

    Tricky integral from calc 3 Arc Length question

    Homework Statement Find the arc length of: r(t)=<e^t, e^(-t),sqrt(2)*t> from 0 to ln(2) Homework Equations L=integral from a to b of the magnitude of r'(t) The Attempt at a Solution Okay, this was an Exam question, the one exam question that I could not get on our Calc 3 exam. This breaks...
  40. V

    Integration of an arc of charge

    Homework Statement Two arcs of charge are center at the origin. The arc at radius r has a linear charge density of +(lambda) while the arc of radius 2r has a linear charge density of -(lambda). (r = 5cm, lambda = 1nC/m, theta = 40°) a) Calculate the magnitude and direction (as an angle from...
  41. RJLiberator

    Arc Length in Three Dimensions Question

    Homework Statement Find the arc length of r(t)= <tsin(t), tcost(t), 3t> from 0 to t to 2pi (inclusive) Homework Equations Integral from 0 to 2pi of the magnitude of r'(t) dt The Attempt at a Solution 1. Must find the derivative of the function. Using the product rule a few times, the...
  42. C

    Arc length of a stadium billiard

    I've been trying to figure out the most straightforward way of doing this for a while, and would like to get some advice on new approaches, as the one I was using didn't work out at all. So here it is: The stadium billiard is defined as two semicircles joined by two tangent lines, as shown in...
  43. Calpalned

    Deriving the formula for arc length of a polar function

    Homework Statement Derive ∫(dr/dθ)^2 + R^2 )^0.5 dθ Homework Equations x = Rcosθ y = Rsinθ The Attempt at a Solution Arc length is the change in rise over run, which can be found using Pythagorean's Theorem. Rise is dy/dθ while run is dx/dθ. The arc length is [(dy/dθ)^2 + (dx/dθ)^2 ]^1/2...
  44. Z

    Kinematics: Traveling in an arc

    Homework Statement Consider a cannonball being fired with a velocity of 30m/s from a cliff of height 45m. http://imgur.com/OCMNEPv (a) Calculate the time taken for the ball to reach the ground. (b) Calculate the range of the motion. (c) Calculate the horizontal velocity, vertical velocity...
  45. J

    Find the arc length (using hyperbolic trig)

    1. The problem statement, all variables and given/known Find the length of the curve $$y=ln(x),\frac{1}{2}<=x<=2$$ Homework Equations Using hyperbolic trig isn't necessary, but it's how my text (Serge Lang's A First Course in Calculus) approaches most square roots, and as a result, it's what...
  46. A

    MHB How to Solve for r and θ in a Circle's Minor Arc and Sector Area Problem?

    The length of the minor arc of a circle is 10cm, while the area of the sector AOB is 150cm2. a) Form two equations involving r and θ, where θ is measured in radians. b) Solve these equations simultaneously to find r and θ. Help to solve? Cant understand the question very well. I think the...
  47. A

    Precalc Trig Arc Length Question

    Homework Statement http://education.Alberta.ca/media/9451970/07_math30-1_released_2014-15.pdf question #7 Homework Equations a=theta*r The Attempt at a Solution I did a=(5pi/6)*20 but the answer is not A
  48. aditya ver.2.0

    Is an Arc Reactor Possible in Real Life?

    Everyone is heard of Iron Man's Arc Reactor. But is such a power source possible??
  49. Euler2718

    Trigonometry Arc Length Problem

    First I'd just like to point out that I'm taking calculus and advance pre-calculus simultaneously (kind of a stupid system) and this is a problem in the pre-calc. 1. Homework Statement 2. Homework Equations Let 'a' be arc length. a=\theta r a = \int_{a}^{b} \sqrt{1+[f'(x)]^{2}} dx...
  50. P

    Arc Length: Definite and Indefinite Integration

    Several authors state the formula for finding the arc length of a curve defined by ##y = f(x)## from ##x=a## to ##x=b## as: $$\int ds = \int_a^b \sqrt{1+(\frac{dy}{dx})^2}dx$$ Isn't this notation technically wrong, since the RHS is a definite integral, and the LHS is an indefinite integral...
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