1. ### I Point Charge above an Infinite Plate

Merged thread deleted first post next post is the first post.
2. ### A slab? Infinite area? Electric field? Help please

The first time I saw this question I had no idea how to do it (as you can see in the figure, I lost a lot of points :s) because I was confused on how to even approach it with area of the slab from all sides being infinity. Right? That's problematic, no? Today, I just tried the problem again for...
3. ### I Gaussian elimination for homogeneous linear systems

Hi, I ask for a clarification about the following: consider for instance a 10 x 12 homogeneous linear system and perform Gauss elimination for the first 8 unknowns. Suppose you end up with 5 equations in the remaining 12-8 = 4 unknowns (because in the process of the first 8 unknowns elimination...
4. ### I Electric Field and Potential in a conductor

So in my textbook (Introduction to Electrodynamics by Griffiths) it said that inside a conductor, the electric field E would have to zero, since if it wasn't the free charges would move accordingly and create a electric field that cancels the original field. But in a question that soon followed...
5. ### A few questions regarding Neutral Objects

1. Homework Statement Hello, I'm learning electricity and I'm having a few conceptual questions regarding the subject ( especially about neutral objects ) which I'm unsure of the answers and I'd be happy if someone could help me: 1. Is the charge density of a neutral object ( doesn't matter...
6. ### Potential of an undefinided cylinder

Homework Statement Determine the potential that creates an undefined cylinder of radius $R$ and density density $\rho$ that is uniformly charged. Homework Equations Gauss's law. The Attempt at a Solution I know that for this problem I can use gauss because it is a cylinder, now I do not get...
7. ### I Can Gauss' Law be used to calculate the electric field generated by a uniformly charged thread?

Hello, Can not Gauss's Law be used to calculate the electric field generated by a uniformly charged finite thread? I suppose it is because I can not consider the electric field constant (always going to the same direction), and for this I would have to do it by parts (the lateral flow, and the...
8. ### Gauss's Law and Parallel Line Charges

Homework Statement Find an equation for the net electric field at a point, above and between, two infinite line charges, one with line charge density λ and the second with line charge density -λ. The point is a distance R from both line charges, a distance y above the midpoint between charges...
9. ### I Understanding Gauss' law: diff b/w E and D flux?

I noticed the other day something odd in how we use Electric and Magnetic flux. The definitions I refer to are magnetic flux density (B), magnetic flux intensity (H), electric displacement field (D) or Electric field density (D) and electric field (E): B = μH ΦB = B*Area & D = εE ΦE = E*Area...
10. ### Is there any way to calculate this integral?

I have done it by the parametric form of σ, but if I change σ to implicit form that is G(x,y,z)=x^2+y*2+z^2-R^2=0 I don't know how continue. The theory is: where Rxy is the projection of σ in plane xy so it's the circumference x^2+y^2=R^2
11. ### Electric force between two spheres

Homework Statement [/B] Find the electric force between the two spheres. Sphere r=b-a has a volumetric density of p=K, where K is a constant Sphere r=a has a volumetric density of p=θ*r Homework Equations As you can see the sphere of radius 'a' doesn't have a uniform electric field because...
12. ### I Shielding an off-center charge with a conducting shell

Hi. I'd like to show that a conducting, charged spherical shell can shield the field of an inside opposite point charge even if this charge is not at the center. I was thinking about a Gaussian surface just outside the sphere, such that if there were electric field vectors they would be...
13. ### I Faraday cage in electrodynamics (with currents)

Hi. Assume a long hollow wire that both carries a nonzero net charge and a current. Is it still true that all charge sits on the outer surface of the cable and that the empty space inside is field-free (Faraday cage)? I know proofs of those facts in electrostatics using Gauss' theorem, but they...
14. ### I Effect of Collimated lens on Gauss Beam

Hello everyone, I am trying to find effect of collimated lens on gaussian beam propagation. Do you know how to solve that? I need any equations ,then going to use them via matlab. Thanks
15. ### B Gaussian gun: Where does the extra kinetic energy come from?

Probably a stupid question, but I do not get it... Here you can see an experiment demonstrating the Gaussian gun: Here I understand how momentum is conserved, i.e. the smaller mass of the ejected ball times its high speed is equal the bigger total mass of the recoiling masses times its...
16. ### B Gaussian Curvature and Riemmanian Geometry

Please bear with me because I'm only in Pre-calculus and am taking basic high school physics. This is completely outside of my realm but curiosity has taken the better of me. I just learned last week about the difference between Euclidean Geometry and Riemmanian Geometry (from another thread...
17. ### Why infinite conducting rod - Gauss's Law , uses lambda?

hi, i still don't understand why infinite thin-walled cylindrical shell or conducting rod use lambda rather than sigma ? lambda = C/m ,,, sigma = C/m^2 i mean when we look at conducting rod, the charges inside the conductor is zero, so the charges spread on the surface of conducting rod(have...
18. ### Verify Divergence Theorem

Homework Statement Verify the divergence theorem for the function V = xy i − y^2 j + z k and the surface enclosed by the three parts (i) z = 0, s < 1, s^2 = x^2 + y^2, (ii) s = 1, 0 ≤ z ≤ 1 and (iii) z^2 = a^2 + (1 − a^2)s^2, 1 ≤ z ≤ a, a > 1. Homework Equations [/B]...
19. ### I think this is about the Central Limit Theorem

Homework Statement An engineer is measuring a quantity q. It is assumed that there is a random error in each measurement, so the engineer will take n measurements and reports the average of the measurements as the estimated value of q. Specifically, if Yi is the value that is obtained in the...
20. ### Conditional Expectation of Multiple Independent Random Varia

Homework Statement Given X,Y,Z are 3 N(1,1) random variables, (1) Find E[ XY | Y + Z = 1] Homework Equations The Attempt at a Solution I'm honestly completely lost in statistics... I didn't quite grasp the intuitive aspect of expectation because my professor lives in the numbers side...
21. ### Capacitors in a series circuit W/ one dielectric

Problem: When a dielectric slab is inserted between the plates of one of the two identical capacitors in Fig. 25-23, do the following properties of that capacitor increase, decrease, or remain the same: (a) capacitance, (b) charge, (c) potential difference (d) How about the same properties of...
22. ### Electric field inside and around a hollow sphere

Hi everyone, I am wondering if anybody could help me out. For my study I got the following question but I got stuck in part C (see image below). I Found at A that due to symmetry all components which are not in Ar direction will get canceled out I found at B that there is only charge density at...
23. ### Gauss' theorem due to thin infinitely long sheet

Our teacher derived an expression for electric field due to thin sheet using gauss law which was sigma/2*epsilon naught which was independent of r but dies that mean the field will be same even if r is 10000km but field is also equal to kq/r^2
24. ### Electric field outside of a cavity

Homework Statement Hi everyone. I m just studying capacitors but I have problems with gauss law. In one exercise it says that we have a sphere(cavity) of radius r, with a charge q placed inside the sphere of it. Wie have to find the electric field inside and outside sphere. The solution says...
25. ### Foundations What's a good book for last year of A levels Maths?

I'm looking for a book to self-study this summer before my last course of Bachillerato (A Levels or High School in other countries). My performance in Mathematics has only improved and I've just been given the maximum mark this last term (10/10 or A+). This has motivated me a lot to keep...
26. ### Basic physics of a coilgun

Hey, I've seen a few posts on this without any responses I really thought helped (at least help answer my question). So, I was hoping somebody on the forums here could help walk me through the basic physics of a coilgun. Basically, how could you characterize the magnetic field inside the...
27. ### Correlation between Iterative Methods and Convolution Codes

Hey guys so I have this Calc 3 project and the end is throwing me for a loop. I've done the encoding part, and i've coded the standard iterative methods, but I don't see how the two correlate so I can use the iterative methods to decode a "y stream" with the inputs specified...
28. ### Solid Insulator Sphere Inside Hollow Sphere Conductor

Homework Statement I was looking for some practice problems in my textbook and found this problem that I was just a little stuck on. I drew the diagram from my textbook with the givens of the problem. Homework Equations ∲E*dA = Q (inside) / ɛ0 The Attempt at a Solution For r less...
29. ### Maxwell distribution in thermal equilibrium

Homework Statement In thermal equilibrium, the particle in a gas are distributed in velocity space according to the Maxwell distribution f(v) = A*exp(-mv^2/(2KT)) What is the average velocity ? What is the most probable velocity ? Homework Equations <v> = ∫∫∫vf(v)d3v = (0 to infinty)...
30. ### Differential form of gauss's law.

I don't understand what charge density is meant in the equation: div E = constant times charge density. I have the derivation in front of me and the last step follows from accepting that the rate of change of the integral of the field divergence per change in volume is the same as the rate of...