Gauss's law Definition and 384 Threads

  1. C

    Deriving Electric Field for a Conductor-Shell System using Gauss's Law

    A long straight conducting rod (or wire) carries a linear charge density of +2.0uC/m. This rod is totally enclosed within a thin cylindrical shell of radius R, which carries a linear charge density of -2.0uC/m. A) Construct a Gaussian cylindrical surface between the rod and the shell to derive...
  2. C

    Deriving Electric Field in a Charged Rod and Shell System"

    A long straight conducting rod (or wire) carries a linear charge density of +2.0uC/m. This rod is totally enclosed within a thin cylindrical shell of radius R, which carries a linear charge density of -2.0uC/m. A) Construct a Gaussian cylindrical surface between the rod and the shell to derive...
  3. N

    Understanding Gauss's Law: Exploring Electric Flux and Charge Distribution

    I have a question about electric flux. Intuitively it makes that if a charge is outside a closed object, then the net flux inside that object will be zero..but once I write it down on paper it loses its sense. I attached a picture for clarification. Flux is equal to the field, times...
  4. S

    Proof Gauss's Law - Understanding, Deriving & Applying

    I was wondering, how would you prove Gauss's law (either mathematically or intuitively)? I mean, I know that sometimes people take it as the fundamental law (one without proof) but how would you derive such a law from Coulomb's law? Any help would be extremely appreciated. I have been fussing...
  5. S

    Solving Electric Fields with Gauss's Law: Doubts and Calculations

    Hello, everyone. I have a problem that I solved using Gauss's Law. However, I am unconfident in my answers, as I have very little experience with Gauss's Law. The surfaces of two large (i.e. infinite) parallel conducting plates have charge densities as follows: \sigma_1 on the top of the top...
  6. B

    Gauss's Law and Flux: True or False?

    Ok guys, these are just questions from our book(like critical thinking type)...she said to be able to understand these, for the upcoming test. I'm not sure I fully understand them(if at all). 1. If a closed surface surrounds a dipole, the net flux through the surface is zero. True or...
  7. S

    Using Gauss's law to calculate magnitude of electric field

    I understand how to use Gauss's law to calculate the electric field at some point for say a sphere with charge distributed uniformly in it. I am bit confused, though, about calculating the electric field at some point for a non-uniform charge distribution. For example, say that I have a...
  8. O

    Gauss's law and the Electric field in an object

    Hey guys, before I post I want to say that I am still learning this concept and just want clarification. Why do the charges inside a metal or other object that are interacting(repelling for instance) eventually come to rest and not continue to keep moving around constantly repelling one...
  9. B

    Applications of Gauss's Law for a hydrogen atom

    First could someone actually explain the following question to me! Consider a hydrogen atom to be a positive point charge e at the center of a uniformly charged sphere of radius R and with total charge -e. Using Gauss' Law, find an expression for the electric field as a function of the...
  10. L

    Help needed with (the point form of) Gauss's law & divergence of E and

    I need to show that \vec{\nabla} \cdot \vec{E}= \frac{\rho}{\epsilon_0} where \rho is the volume charge density. I know that if I can show that the net flux of the electric field (in three directions xyz) out of the a small gaussian surface in the shape of a cube with faces parallel to...
  11. H

    What Fraction of Total Charge Lies Between (R/2) and R?

    A region in space contains a total positive charge Q that is distributed spherically such that the volume charge density rho (r) is given by: rho (r)=3 * alpha * r /(2R) for r ≤ R / 2 rho (r)= alpha * [1-(r/R)^(2) ] for (R/2) ≤ r ≤ R rho (r)=0 for r ≥ R Here alpha is a positive...
  12. F

    Where Did I Go Wrong? Investigating Gauss's Law with Multivariable Calculus

    Okay, first off, some quick background. I am a student in AP Physics C, and I like to think I generally have a good grasp of physics (I read about it outside the class). We just learned about Gauss's Law this week, and I have a good grasp of it. I understand how it can be used to simplify some...
  13. D

    Gauss's Law: I need to check this answer

    A conducting sphere of radius 10 \mbox{ cm} has an unknown charge. If the electric field 17 \mbox{ cm} from the center of the sphere has the magnitude 3.2 \times 10 ^3 \mbox{N/C} and is directed radially inward, what is the net charge on the sphere? Let: R = 10 \mbox{ cm} r = 17 \mbox{...
  14. E

    2 Problems regarding Gauss's Law

    Hey everyone, I have two problems that deal with Gauss's law. The first one deals with Electric Fields. Charge is distributed on a long, straight rod with uniform density 6.5 x 10^-8 C/m. Compare the magnitude of the field 1 cm from the rod to the field 1 cm from a point charge q = 6.5 x...
  15. G

    Gauss's Law and E field problem

    I have two plates, one on top of the other, that have a charge densities +s1 of the top of the top plate, -s2 on the bottom of the top plate, s2 on the top of the bottom plate, and -s1 on the bottom of the bottom plate (s1 and s2 are both positive numbers). I have to find the electric field on...
  16. E

    What is Gauss's Law? | Simple Explanation for High Schoolers

    I'm a senior in high school, and I have a physics research paper due on Thursday. The problem is, I don't know what Gauss's Law is. So I googled it. In physics, Gauss's law gives the relation between the electric flux flowing out a closed surface and the charge enclosed in the surface. I...
  17. F

    How Does Charge Distribution Affect Electric Field in Nested Cylindrical Shells?

    A thin cylindrical shell of radius R1 = 5.0 cm is surrounded by a second cylindrical shell of radius R2 = 9.0 cm, as in Fig. 22-34. Both cylinders are 3.0 m long. The inner one carries a total charge of Q1 = -3.8 µC. The outer one carries a total charge of Q2 = +2.2 µC. (Assume the positive...
  18. F

    What is the Electric Field for a Charged Sheet at Different Distances?

    A flat square sheet of thin aluminum foil, 25 cm on a side, carries a uniformly distributed -36 nC charge. What is the approximate electric field at the following positions? a.)0.01m above surface? b.) 20m above the sheet? For a.), I used E=chargedensity/(2)epsilon. From my...
  19. A

    Gauss's Law and a conducting sphere

    "A solid conducting sphere with radius R carries a posative total charge Q. The sphere is surrounded by an insulating shell with inner radius R and outer radius 2R. The insulating shell has a uniform charge density \rho a) find the value of \rho so that the net charge of the entire system is...
  20. Q

    How Does Gauss's Law Calculate Charge on a Cylindrical Shell?

    I am stuck on this one. I apprciate your help greatly. A cyllindrical shape of radius 7cm and length 240 cm has its charge uniformly distributed on its curved surface.The magnitude of the electric field at a point 19cm radially outward from its axis (measure from the mid point of the shell)...
  21. S

    Solve Gauss's Law: Electric Flux Through Sphere from Line Charge

    An infinitely long line charge having a uniform charge per unit length (half-life - if anyone could tell me the correct name for that symbol it would be great too :)) lies a distance d from the point O, where the point O is the center of a sphere. Determine the total electric flux through the...
  22. T

    What is the explanation for Gauss's Law and the concept of electric flux?

    Hi all, Can someone give me a better explanation of precisely what Gauss's law and the term "electric flux" mean (better, that is, than Giancoli 6th edition, where they never really define it ). I just want to get a handle on the concept in general. Thanks ~
  23. quasar987

    Proof of Gauss's Law: Connecting Flux and Closed Surfaces

    See the "Gauss's Law Sketch Proof" paragraph .[/URL] Griffiths uses mainly the same argument to prove Gauss's law, but I don't really see the connection between the fact that the flux is Q/epsilon for a sphere and the conclusion that it is worth this quantity too for any closed surface. Can...
  24. C

    Charges on Conductors and Gauss's Law

    Can someone give me a couple hints to get me started on this problem, I am not sure where to go next. Infinite line of charge has charge per unit unit length 4.8*10^-6 and lies along the x axis. A second uniform line of charge with charge/unit length -2.4*10^-6 is parallel to the x-axis at...
  25. P

    Solving Gauss's Law Problem for a Solid Cylinder

    An infinitely long solid cylinder radius R1 lies with it's central cylindrical axis lying along the x axis. it is made of a non-conducting material. It has a volume charge density that varies with readius as follows... p(r)=A.r (C/m^3) where A is a constant. Consider a cylindrical Gaussian...
  26. A

    How Does Gauss's Law Change in Dielectric Materials?

    Hey everyone, this is my first question on here, but I've seen you all be very helpful to others to I was hoping someone could clarify something for me. 1. How does Gauss law modify in dielectric materials?
  27. cepheid

    Gauss's Law: Cylindrical Symmetry

    Problem : A long coaxial cable carries a uniform volume charge density \rho on the inner cylinder (radius a ), and a uniform surface charge density on the outer cylindrical shell (radius b ). The surface charge is negative and of just the right magnitude so that the cable as a whole is...
  28. Cyrus

    Gauss's Law and an irregular shape

    Gauss's Law HELP! I need some help with Gauss's Law. In the book it states that if you have an irregular shape, then you can project each piece of that irregular shape onto a sphere. And since a sphere has field lines everywhere perpendicular to it, it makes life very simple because the flux...
  29. 6

    Calculating Electric Field Strength at a Corner with No Charge

    I'm encountering a problem with a practice test and previous homework problem in my electrostatics class. Charges exist at three corners of a square as shown. Edge length = L. What is the Electric Field Strength (E) at the corner with no charge. -3q O------------O +2q...
  30. S

    Electricity & Magnetism Tutorials - Need Help with Gauss's Law

    Hello, I was wondering if anyone has any links to any Electricity & Magnetism tutorials. I don't understand very well and was hoping for maybe an online book or something. Our lecture textbook sucks. We are doing Gauss's Law. Thanks!
  31. S

    Understanding the Charge Distribution in a Coaxial Cylinder System

    First I set about to calculate the electric field: Solve for Q with the capacitance of two coaxial cylinders: substituting: Where 'r' is a distance measured from the center. Trying several distances (r = 5cm -> E = 69.2 Volts / meter, r = 2cm [on the internal cylinder] -> 432.8 Volts...
  32. E

    How Do You Calculate Electric Fields of Spherical Charges Using Gauss's Law?

    Here is the problems that's giving me trouble: Positive charge Q is distributed uniformly over each of two spherical volumes of radius R. One sphere of charge is centered at the origin and the other at x=2R. Find the magnitude and direction of the net electric field due to these two...
  33. E

    Solving Gauss's Law Problem: Find Electric Field at Point

    Here's the homework problem I'm having trouble with: A solid metal sphere of radius .4 m carries a net charge of .190nC. Find the magnitude of the electric field at a point .130 m outside the surface of the sphere. I used the equation EA=q/Epsilon_0 E(4*pi)(r^2)=q/Epsilon_0...
  34. P

    Gauss's Law and a uniformly charged cube

    I can't seem to figure out how to apply Gauss's law to a uniformly charged cube(side length a), charge density = rho = Q/a^3. Here's the problem: I have a uniformly charge cube, of side length 'a,' with total charge Q which has a conductor on two oppossing faces. I want to know the electric...
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