Electric Definition and 1000 Threads

Just as the title asks, I wonder if there can be any electric field inside an insulator when a point change is placed near it. If so, why?

Hi everyone. I've been doing a lot of reading regarding electric potential and electric potential energy. Unfortunately, I have a lot of confusion regarding this topic, as I keep receiving different information. My main confusion is regarding the signs, positive or negative, of work and it's...

Homework Statement Hi guys, I was hoping I could get some help on this question! The question: "Find the electric field at the point 20 cm above the center of the square made of 4 charged rods of L = 20cm and Q=1mc each. Homework Equations I believe E = (KQ)/r^2 is the only equation needed...

Four identical particles, each having charge q and mass m, are accelerated from rest at the vertices of a square of side L. How fast is each particle moving when their distance from the center of the square doubles? I used the Conservation of Energy => Kf= -deltaU = Ui-Uf 4(mv^2 /2) = kq^2...

Homework Statement A particle of mass 7.3 × 10−5 g and charge 24 mC moves in a region of space where the electric field is uniform and is 6.3 N/C in the x direction and zero in the y and z direction. If the initial velocity of the particle is given by vy = 4.1 × 105 m/s, vx = vz = 0, what is...

Homework Statement A cylinder of radius R= cm 1.2 and length L= 51 cm has a charge Q=2.3 μC spread uniformly along its surface (and not on its flat ends). a) Calculate the electric field strength a distance d=4 mm from the cylinder’s surface (not near either end) b)Calculate the electric...

What is the value of electric field at the surface of a spherical shell?

Homework Statement Hello everyone, I am writing here regarding a doubt I have about electric fields. Our set up consists on two rod shape electrodes in a cylindrical glass vessel separated by 6 mm from each other, with one of the electrodes grounded (electrodes dimensions: 0.5 mm diameter and...

wich creates an electric field charge or a charged particle (electron)

what is difference between electric field and electrical charge?

If a single point charge is moving, then the component of the electric field normal to the motion is larger (by the gamma factor) than if the charge were stationary. Now consider an infinite line of charges (with a small separation, the same between each charge). If the whole line is moving...

I notice from the classic electric field line diagram of two positive charges that there is no field line going along the line segment joining those two charges. So I wonder whether that is true or it's just a way that you can't show all the field lines in the diagram but it actually exists. (I...

Hi, I am trying to understand capacitors and have come across the example in the attached image. What I would like to understand is how to calculate the electric field at some distance x within the capacitor. With x>>R , x<R and x=R . The image is of two circular disks as the...

That is, a field that accelerates charges in opposite directions on each side of an axis. I was thinking about interference of similarly polarized waves traveling in opposite directions (so that electric field peaks and valleys overlap but magnetic field adds constructively) - would there be an...

I found that the electric field at r=0 equals infinity. What if two negative charges were put infinitely close together so the electric field was infinite, then would the charge of those two points be -infinity as well?

Is it possible to create a material that will block an electric field like mu-metal blocks magnetic fields?

Homework Statement Homework EquationsThe Attempt at a SolutionThe emf gets induced due to the changing flux. The flux through the rod remains 0. So, there is no induced emf. I don’t know how to calculate induced electric field. But as there is no induced emf, so there is no induced...

Homework Statement Homework EquationsThe Attempt at a Solution The radiations from the bulb spread radially outwards such that "Power at a distance r" = Power radiated/4πr2 . If distance is unchanged and power halved then the intensity should also be halved . From this I get E' = E/2 ...

[Moderator note: moved from general physics, no template.] This is a solved example given in the book . Could someone help me understand how amplitude of electric field has an inverse relationship with distance ? Only the very basics of EM waves are covered in the book so I would appreciate...

Why the negative pole of a battery is said to be of higher potential? While if we a consider a DC battery of 12V (for instance) then we have Vpn=V (positive) -V (negative)=12V whish is a positive quantity, then we should conclude that Vp>Vn in contradiction to first statement! Please illustrate...

Hi, so I was hoping to get an EE's explanation for what just happened. So my son was apparently over by the light switch pointing a UV pen light at the switch. Suddenly there was very loud, gunshot-like pop, sparks flew, and I had to go reset the breaker. Maybe correlation doesn't imply...

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?

Homework Statement Two conducting hollow spheres are are placed concentrically, the inner sphere have a radius ra = 5 cm and the outer sphere have a radius rb = 15 cm. The charge on the inner sphere is qa = 4 · 10−7 C and qb = −4 · 10−7 on the outer sphere. (a) Use Gauss’s law to find the...

Homework Statement Two large, flat metal plates are held parallel to each other and separated by a distance d.· They are connected together at their edge by a metal strip. A thirt plastic sheet carrying a surface charge \sigma per unit area is placed between the plates at a distance 1/3*d from...

Homework Statement Find the general formula for the x component of the electric field if the charge density p varies only with x throughout all space. Homework EquationsThe Attempt at a Solution I started using the poisson equation \bigtriangledown \bullet \bar{E} = \frac{p}{\varepsilon_{0}}...

Homework Statement Two parallel plates located at a distance "L" from each other they maintain a potential difference "V" because of a battery (as shown in the picture). Through a small hole, made in bottom plate, electrons get into system (with mass "m" and charge "-e"), with velocity "v" and...

Homework Statement The electric guitar radiates very little sound directly, but instead relies upon pick-ups (transducers) placed beneath the strings. Establish, showing clearly how you reach your answer, which harmonics of the open string you are likely to observe if the pick-ups are placed...

Homework Statement [/B] It is required to find the current through the ammeter, marked A, in the above figure.Homework Equations ##V=iR##The Attempt at a Solution I've redrawn the circuit as follows - But don't know how to obtain the value ##i_3##

Hi Guys, I have attempted the question below. Please have a look at my work and let me know if everything looks fine. Any feedback would be great. 1. Homework Statement Homework Equations F = qv/d a = F/m t = d/v qv = 1/2mv^2 x = vt + 1/2 at^2 The Attempt at a Solution

Homework Statement I am trying to figur out whether there is or isn t an Electric Field along the surface of a cylindrical current carrying wire With radius r and length L, current I and resistance R. I was trying to see if someone already asked this and i found one discussion, however where a...

Homework Statement An electric dipole instantaneously at rest at the origin in the frame K' has potentials \Phi'=\mathbf{p}\cdot\mathbf{r}'/r'^3 and \mathbf{A}'=0 (and thus only an electric field). The frame K' moves with uniform velocity \mathbf{v}=\vec{\beta }c in the frame K. Show that in...

I’ve looked at the answers given to the previous times this question has been asked, but I still don’t seem to understand how this holds in the case of a closed circuit. Here’s an explanation given before: “Think of the wire as a horizontal cylinder. If you apply an electric field pointing to...

From wikipedia: "An electromagnetic wave such as light consists of a coupled oscillating electric field and magnetic field which are always perpendicular; by convention, the "polarization" of electromagnetic waves refers to the direction of the electric field." A polarizer is an object that...

I am confused how a charge could have negative work done. To clarify, I was doing a problem earlier in which a positive charge and negative charge are moving towards each other. I used the equation work = Δv * q And when I was doing this, the change in electric potential, Δv, was negative, and...

Hi. I am having some trouble understanding what is the voltage drop in a system with resistors in series. If there is a difference of electric potential between two points in space, since electric potential is electric potential energy per charge, there is a difference in the electric...

I have been building a electric lighter without soldering since I don't know how to solder, so I am going to ask my brother to show me how on the weekend. Until then I've been using alligator clips, 9 volt batteries (preferably one) and graphite from pencils as a resistor. Unfortunately the...

Hi people, me bother yo again! I understand that relativity theory length contraction is the explanation of magnetics fields. See the image: https://dl.dropboxusercontent.com/s/vuy69jhig3kni3n/densidadcargasencorriente.jpg?dl=0 1) In the S system, if q is moving at the same velocity than the...

The Bohr magneton is (see e.g. Wikipedia) in SI units: $$\mu_B=\frac{e\hbar}{2m_e}$$ and in CGS units: $$\mu_B=\frac{e\hbar}{2m_ec}$$ So the dimension of the electric charge in SI, ##[q_{SI}]##, is related to the dimension of the electric charge in CGS, ##[q_{CGS}]##, by...

Homework Statement A metal rod of mass M and length L is pivoted about a hinge at point O as shown in Figure P32.80 (I have attached this to this post) The axis of rotation passes through O into the page. Find the ratio of the maximum electric field inside the rod to the applied magnetic field...

Homework Statement A semi-circular wire containing a total charge Q which is uniformly distribute over the wire in the x-y plane. the semi-circle has a radius a and the origin is the center of the circle. Now I want to calculate the electric field at a point located on at distance h on the...

Homework Statement Find the total electric charge in a spherical shell between radii a and 3a when the charge density is: ρ(r)=D(4a-r) Where D is a constant and r is the modulus of the position vector r measured from the centre of the sphere Homework Equations Q=ρV Volume of a sphere =...

Homework Statement A parallel plate capacitor has 2 square plates of side l, separated by a distance d (l is a lot bigger than d). Between the plates, there is a linear and non-homogeneous dielectric with constant $$\epsilon_R=1+ay$$ with $$a$$a positive constant. Calculate the electric field...

Homework Statement Homework Equations F=qe, a= qe/ma, x= vit + 1/2t^2 The Attempt at a Solution (a) i used the formula a= qe/ma to calculate the acceleration and then substituted in this kinematic equation x= vit + 1/2t^2 then i solved for t taking the initial velocity as zero. (b) i used...

For a fixed point in space, the first-order electric field correlation function may be given as (Possibly incorrectly, see my "second" post to this thread)! $$\langle\vec E^*(t)\vec E(t+\tau)\rangle = {\frac {1} {T}} \int_T\vec E^*(t)\vec E(t+\tau)dt~~~~~(1)$$ Where T is a very large time and *...

Homework Statement Hi! So I stumbled upon this simple "plug n' play" exercise in my Physics textbook. Basically it gives you certain molecules/atoms, and tells you to measure the Electric Charge, and its Mass. Pretty simple, but I hit upon some hickups. Anyway, let's get to it: Find the...

Homework Statement Four protons (each with mass 1.7 10-27 kg and charge 1.6 10-19 C) are initially held at the corners of a square that is 7.1 10-9 m on a side. They are then released from rest. What is the speed of each proton when the protons are very far apart? (You may assume that the...

Homework Statement In a lab experiment we measured the potential at different points within a cylindrical capacitor electric field modeling plate thing (apparently that's the best I could do to translate that into English). The positive electrode was connected in the middle and the negative...

Homework Statement [/B] Here's the problem from the homework. I've called the initial positions in order as 0, l, and 2l. Homework Equations The most important equation here would have to be |V - w2*M| = 0, where V is the matrix detailing the potential of the system and M as the "masses" of...

Imagine that I have a straight, statically-charged, cylinder-shaped tube with arbitrary (ideally infinite) extent. The charge is distributed evenly over the tube such that the field inside the tube is zero. For convenience, let's line up the tube centered along the x-axis such that the...

I have what at first seems like a very simple problem, yet I have no clue how to solve it. There is 1 point defined to have 0V, and another point has exactly 1V. Assume there is nothing else in the universe. https://i.imgur.com/iv9oL5j.png How do I find the electric potential and field at any...