Electric Definition and 1000 Threads

Hello! Is it possible to build a setup (containing time dependent and independent electric fields), such that a charged particle will feel a force proportional to its velocity i.e. ##ma = -\alpha v##?

I have been having a hard time understanding Electric Potential and believe I finally have a grasp on what is trying to say. I wanted to right out my understanding here and hopefully have someone confirm what I am saying is somewhat accurate as I feel like when you write stuff out you tend to...

So the change in potential energy is ∆U = Uf-Ui. Final minus initial. If i solve the above problem like this I end up with a negative value. The way the person in the attached work solved the problem, is they used ∆U = Ui-Uf. How are the switching Ui and Uf? What is it I am missing?

I am having trouble understand where area circled in red. I get that lamda is Q/L. The charge is +Q. Length is pi/R/2. I am having trouble understanding why the length is pi/R/2? Is it because the circumference of a circle is 2*pi*R and since we have broken this problem down to just...

Hi , I've been trying to manage a solution in my head and i think I'm on the right path , i just need some approval and maybe some tips. So it's obvious I can't solve this without integration because law's only apply to point charges , and i can't shrink this object to a point as i could do with...

A science team from the university of Kassel (Germany) proved with a physical model, that a moderate electric field inactivates the Convid-19 virus. Source: https://www.nature.com/articles/s41467-021-25478-7 via...

I have tried to understand the solution given in the book which is as pasted below. The solution uses Gauss's Law but makes no mention of which Gaussian surface is used. The diagram that I have used to understand this problem is also given at the end. From the diagram, faces OADG, OABE and OEFG...

I noticed that in some textbooks (Physics - Tipler) the electric flux formula is different than in other textbooks (Engineering Electromagnetics -W. Hayt) Which one should we use?

My understanding is that the uniform electric field ##\vec E## cannot be the net electric field since the dipole creates its own electric field as shown in first diagram below, which must superimpose with the uniform electric field. So, yes, the uniform electric field ##\vec E## around the...

In a previous thread* the field in a charged ring was discussed and it was shown to be not zero except at the center. In *post #45 a video is referenced that says the field diverges as one gets close to the ring and it was argued that at very close distances the field looks like an infinite line...

Example of emf due to Lorentz magnetic force is motional emf. When rod PQ moves to the left, there will be downwards magnetic force acting on the positive charge in the rod PQ so point Q is at higher potential compared to point P so there will be potential difference (emf) between P and Q The...

The first part of the problem seems easy enough, the free electrons in the wire would move in a circle owing to an electric field that would be induced in the rod which would provide the centripetal force for the same (Please correct me if I am wrong). So we have $$eE=mω^2x$$, where e is the...

I am wondering if the phase diagram of Carbon has been explored at very large electric fields. Can one make any theoretical guesses ? In specific I am interested in Pressure Vs Electric field and Electric field vs Temperature at fixed temperature and pressure respectively.

In the 7th edition of the book "Elements of Electromagnetics by Matthew N. O. Sadiku" On page 190 the author goes on to say: "We now consider the case in which the dielectric region contains free charge. If ##\rho_v## is the volume density of free charge, the total volume charge density...

Hello All! You know sometimes you touch another person and you felt an electric spark between both of you, or sometimes with things like the door handle, etc. I moved lately to a hot and dry country where the temperature is around 40-45 Celcius degrees now in August, but since I moved here this...

I have broken the ring into a top arc and a bottom arc. First, let's assume an imaginary charge of +1 C is placed at point P. We will determine the force on this unit charge from top and bottom arcs. The charges in the top arc will result in electric fields that will all cancel each other...

Good afternoon to everybody. I have may be a stupid question according to the tangential part of the electric field near the surface of the conductor. Why is it zero? The normal part is zero on the distance of Debye cause of screening. But is this situation the same for horizontal direction...

When I look at the relevant equations, then there is no mention of field for a point on the surface of the shell, so it gets confusing. On the other hand, I feel the radial E will get stronger as we approach the surface of shell and magnitude of E will approach infinity.

Summary:: Given a known closed space/apparatus ( e.g. constant volume, pressure, density, current, temperature, voltage, spark gap distance - let me know if I missed something) how would I compute the change in gas temperature. Hello, Given a known closed space/apparatus ( e.g. constant...

When I look at this question, I can see two possible values of electric flux depending on how I take the normal area vector for either ends ##A \text{ and } A^{'}##. What is wrong with my logic below where I am ending up with two possible answers? The book mentions that only ##2E\Delta{S}## is...

Gauss law relates between E at some point on guassian surface with the net charge enclosed by that surface. Using gauss law is like being able to tell what (ie charge)is inside a gift box by just looking at the wrapper(electric field). There are two types of problem. Sometimes we know the charge...

I bought an EMF meter that can discriminate to electric fields, and it is highly sensitive to the proximity of my body. What is it in the human body that emits electric fields? Is it muscle activity? Maybe many things in the body? Thanks.

The only explanation that I have seen in textbooks is that since the outer spherical shell is symmetrical relative to internal charged spherical shell so field every where on the outer shell is same in magnitude at every point on it. I can understand that electric field needs to be...

I have figured out how the force is towards left in the first case. I think it is due to the larger force on - charge. Please help me out with the second and third case.

I think Flux density is flux/Volume. Or is it flux/ Area Please be kind to help

I don't understand the exact meaning of flux. Please be kind to help.

I was wondering, we constantly assume the reference of zero potential is the surface of the Earth. But if we consider the reference to be the infinity, what would be the electric potential of the Earth? As Faraday says, the Earth is charged with a -580 kC of negative charge. If we consider...

k(q_1-q_2)/(R^2+x^2)^3/2

A wavefront is defined as a surface in space where the argument of the cosine has a constant value. So I set the argument of the cosine to an arbitrary constant s. ## k(\hat{u} \cdot r - c t) + \phi = s ## The positional information is is in r, so I rearrange the equation to be ## \hat{u}...

I am thinking about how an electric field has energy associated with it. If a single electron exists alone in a remote vaccuum, I believe it has it's own electric field surrounding it, and that this field has an energy content associated with it. My question is; does this electric field store...

Solution attempt

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So I have a ring(red) of uniform charge ##\lambda## per unit length, and I want to calculate the electric potential at the origin (actually on any point of the ring). It is clear that the ring is given by the equation $$r=2 R \sin \theta$$, in polar coordinates, where R is the radius of the...

My wife said that she saw a very strange aircraft yesterday being chased by a helicopter that appeared to be dangerously close. It was actually a crew making a promo film for a new electric airplane. We discussed electric airplanes last year in another thread. But that topic was very open...

I can calculate the fields generated by the cylinder and the wire but I don't know how to calculate their vector sum to evaluate it at point A. Cylinder field inside: ρR^2/2rε Cylinder field outside: ρr/2ε Field generated by the wire: λ/2πr I should break the fields into components but I don't...

I used the concept of electrostatic induction, which would cause the charges in metal ball near the ebonite rod to have +ve charges on end next to rod and a -ve charge on the end touching the other ball. What confuses me is how charges separate on the second ball. The only way these balls can...

Consider a region where a 25-volt-per-meter electric field and a 15-millitesla magnetic field exist and are along the same direction. If the electron is in the said region, is moving at a direction 20 degrees counter-clockwise from the direction of the magnetic field, and is experiencing a total...

[New poster has been reminded to show their best efforts to work the schoolwork problem when starting a homework thread] My question is : An electron beam with velocity vector v = (0; 0.6x10^8 ;0) m.s enters between two oppositely charged plates parallel to the xz plane. - How large is the...

I'm not quite sure where to start. If someone could help me I would very much appreciate it.

Non-relevant background So, in the dim time, we had a microwave link installed for our internet service. The dish was on a mast on the second story (about a foot square, no idea what frequency). The installers put in a grounding 1/2 inch diameter rod. I remember because of more than an hour of...

Hi guys ! I am taking phys102 course .I figured out that i didnt fully understand the concept that is the Voltage. Please look at this question. In this case we can see that there is no voltage in point C and there is no electric field is in point D and as you know V=U/q .So i always thought...

The question I'm in doubt about is The motor coil has a resistance of 10 Ω and is powered by a voltage of 120 V. When the motor is operating at rated speed, its emf is 70 V. Thus, it is questioned: a) What is the coil current when the motor is started? b) What is the coil current at rated...

What changes occur in electron, whenit through in a electric field

I thought it might be the case that the "2m away" wasn't applicable as the electric field doesn't change if the point away is less than the length of the plate, so I thought I should use the equation listed. All examples I can find talk about two charged plates, or the effect on cylinders...

I understand that negative charges create electric fields pointing inwards, and positive charges create electric fields pointing outwards, but what does this have to do with field stength? What is the relationship between field strength (flux?) and direction?

I used a couple ways to do this question, but I got neither correct. Can someone help, please? Thank you. 1. E= V/r = 700 / (60*10^-3) = 11667 (very far from the given answer) 2. E = (-kQ/r)⋅ dr = kQ/r^2 = kQ/ [( 1/20/ 10^-3)^2 - (1/80/10^-3)^2] (For this method, I stuck...