Charge Definition and 1000 Threads

Homework Statement What is the force F (a vector) on the -10 nC charge in the figure? Give your answer as a magnitude and an angle measured cw or ccw (specify which) from the +x-axis. The figure shown is in the shape of a rectangle. On the top left is a +15 nC charge; on the top right is a...

Homework Statement http://imgur.com/a/wEUgn question #70 in the attached image. Three charged spheres are at rest in a plane as shown in the figure. Spheres A and B are fixed, but sphere C is attached to the ceiling by a thread. The tension in the string is .240 N. Spheres A and B have charge...

Hi, I'm recently reading something which briefly introduces C symmetry. So the thing that confuses me is that how does the spatial wave function contribute the (-1)^L factor? Thanks!

Homework Statement I have to find the charge ##q## on the capacitors (all have capacity ##C= 4 \mu F##) and ##\mathscr{E} = 12 V##, ##R=50 \Omega##Homework EquationsThe Attempt at a Solution I wrote the nodes current equations ##\begin{cases} i_{1}+i_{2}=i_{3}\\ i_{3}=i_{4}+i_{5}+i_{6}\\ ...

Homework Statement 2.75 mC is uniformly distributed on a ring of radius 8.5 cm. Find the electric field on the axis at (a) 1.2 cm, (b) 3.6 cm and (c) 4.0 m from the center of the ring. Homework Equations [/B] E = (kQx)/(a^2+x^2)^(3/2) 3. The Attempt at a Solution This question really boils...

Homework Statement Two conducting spheres having same charge density and with radius “R” & “2R” are brought in contact and separated by large distance. What are their final surface charge densities ? Homework Equations No equation in question. The Attempt at a Solution Tried using the fact...

Hi guys I'm creating a prop that's probably going to have a 7,4V 5000 mah 45C RC Lipo battery in it, and I'm planning to keep it permanent in the prop with a charge circut to charge it up with usb perhaps. I've thought of using a tp4056 circuit I have laying around and it seems like the...

Homework Statement A uniform circular ring of charge Q=4.20 microCoulombs and radius R=1.30 cm is located in the x-y plane, centered on the origin as shown in the figure. What is the magnitude of the electric field E at point P, located at z=3.70 cm? I have worked out the problem and got the...

I've read about the equivalence between inertial mass and gravitational mass. But i can't undestand why is gravity more special then other kinds of force. I mean, why isn't charge equivalent to inertial mass? After all charge plays the same kind of role of gravitational mass in another context.

Hi there, Im familiar with the concept that electric field has associated energy with it Now if in space an electron apppeared at some instant t=0 then electric field will not be established instantaneously but will propagate at speed of light through space As electric field is bieng...

Homework Statement Two small, identical conducting spheres repel each other with a force of 0.050 N when they are 0.25 m apart. After a conducting wire is connected between the spheres and then removed, they repel each other with a force of 0.060 N. What is the original charge on each sphere...

I am trying to create a high DC voltage output(with extremely low current output). I thought of something like this. The left coil would be the tesla coil. Can I use this to charge the capacitor and create high DC voltage? What would happen if capacitance was really high?

1. The problem statement, all variables, and given/known data Suppose you have a wire of length l and a uniform line charge density λ. Find the electric field at the midpoint that is height r above the x-axis Homework Equations (see attached) The Attempt at a Solution To solve, I used the...

Hello, I think I solved the question, but I am confused by the elaboration on the exercise given by my professor. 1. Homework Statement A very large plate charged with charge Q is placed between x = -d and x=0. A similar plate charged with charge 3*Q/2 is placed between x = 3*s and x = 3*s +...

Homework Statement Consider a straight line segment of 3L and with a linear charge density λ. Determine the electric field, E, of at point P, which is a point within the segment and along the axis. (figure attached) Homework Equations dE=kdQ/r^2 The Attempt at a Solution I attempted solving...

In this image charge q is enclosed within an arbitrary shaped conductor. I'm asked to find what if the Electric field in regions 1,2,3,4 are uniform and if the surface charge densities on the interior wall of the arbitrary shaped conductor and the hollow sphere conductor are uniform. My...

Homework Statement A positively charged nonconducting solid sphere of radius R has a nonuniform volume charge density given by ρ0 for r≤R/2 and given by 2ρ0(1−r/R) for R/2 ≤r≤R, where r is the radial distance from the sphere center.Part A Determine the charge q on the sphere in terms of ρ0 and...

Homework Statement Consider a uniformly charged cube with uniform charge density ρ.The ratio of electrostatic potential at the centre of the cube to that of one of the corners of the cube is? A hint on how to approach the problem's solution would be appreciated.(whether to use gauss law or not...

Hello, I made a scale horizontal axis wind turbine that I would like to connect to my phone to charge it. I am trying to decide which motor to buy. Here is my plan and question: Plan: The wind turbine uses a 12 volt dc motor so that when the wind makes the motor shaft rotate there is a...

Hey How can i calculate the work done by a homogeneous electric field on a positive charge q = 7 × 10^-8 C when the charge moves from point 1 to point 2 . I have two cases: a) the charge is parallel to the Electric field; b) the displacement of the charge takes place at the angle α = 60 ° to...

Homework Statement A nonconducting sphere of radius r0 carries a total charge Q. The charge density ρE increases as the square of the distance from the center of the sphere, and ρE=0 at the center. a) Determine the electric potential as a function of the distance r from the center of the...

Homework Statement q=1.602*10^-19 point 1 L=1mm=r1 v=1.1*10^6 at point 2 F=1.44*10^-12 at point 1 Homework Equations E=(1/4πε)*(q/r) ΔV=∫E*dr=(1/4πε)*q∫(1/r)=(1/4πε)*q*ln (r2/r1) ΔU=ΔK=mv^2/2 ΔK=mv^2/2=ΔV*q=q*(1/4πε)*Q*(ln(r2/r1))...

Say, we have two particles of equal and opposite charge in an isolated system in which we neglect gravity. The energy of particle 1 is: E1 = U1 + T1 Where U1 is electrostatic potential energy and T1 is the kinetic energy of particle 1. The energy of particle 2 is: E2 = U2 + T2 Where U2 is...

Homework Statement Homework Equations ##q = CE(1 - e^{-t/RC})##The Attempt at a Solution I assumed that, since the problem specifies that sufficient time has passed, it meant to say that enough time passed. thus making the exponential term in the equation go down to 0, and the charge in the...

Homework Statement Hello, this is more of a conceptual question than a concrete homework assignment question. I'm learning about Gauss's law and the Prof did an exercise on a sphere with uniform charge distribution, where he found E(r). The trick was, that E(r) was constant over the Gaussian...

Homework Statement Given that we have q1 = -4nC on the y-axis at y=0.60m. q2 on the y-axis at y= -1.20m. What must be the sign and magnitude of q2 be for the net electric field at the origin to be: a. Zero b. 50 N/C Homework Equations E=KQ/R2 The Attempt at a Solution I used: ET = E1 + E2...

Homework Statement Homework Equations Circuit Equations. ##U_C=Q^2\2C## ##U_L=Li^2\2## The Attempt at a Solution For (a) I said ##100J## .But I think it might be ##200J## too.Here what I did; ##U_t=Q^2\2C## and I put ##Q=0.1C## and we know ##C##.Here I...

So I am aware the charge conjugation operator changes the sign of all internal quantum numbers. But I was wondering how it acts on a state such as ## \left|\pi^{+} \pi^{-} \right>## when the individual ##\pi's## are not eigenstates of C. I believe the combination of the ##\pi's## has eigenvalue...

Homework Statement We have a spehere of radius ##r_1## and on of ##r_2## far away from each other. The first sphere has a charge ##Q##. What is the change in electro static energy when they are connected together? Homework Equations Potential of a charged sphere: ## V = \frac{Q}{4\pi\epsilon_0...

Homework Statement We have two metal spheres of radii ##R_1## and ##R_2## placed far apart. Given total amount of of charge ##Q## to distributed between the two spheres, how should you do it so that the potential of given distribution is as small as possible. Homework EquationsThe Attempt at a...

Some things I did not get are, 1): In the third para, it is said that potential approaches ##\infty## at ##Q##, why ? 2): In last para, The z component of field by ##Q## is said to be ##-Qh/(r^2 + h^2)^{3/2}##, Why ? should not it be ##+Q## not ##-Q## has the charge itself is positive. 3): I...

Homework Statement Charge is distributed uniformly over a large square plane of side l, as shown in the figure below. The charge per unit area is σ. Determine the electric field at a point P a distance z above the center of the plane, in the limit l -> infinity.. Homework Equations please...

Homework Statement Two 3.0-cm-diameter aluminum electrodes are spaced 0.50 mm apart. The electrodes are connected to a 200 V battery. Find the capacitance of one of the spheres. Homework Equations [/B] C=QV C=ε0A/d The Attempt at a Solution [/B] I'm really not sure how to approach this...

Lets suppose we have a charge and we want to accelerate it from a point A to B and back. Does the energy requirement increases if we move the charge quicker? I can make an analogy with mass. To accelerate an object over a distance d requires energy. The objects resist to change in velocity. The...

Homework Statement The Attempt at a Solution Top left: No charge flowing through circuit b/c switch is open, not closed. Top right: No charge flowing through circuit b/c circuit does not connect positive and negative terminals Bottom left: Charge flows through circuit b/c closed loop between...

Homework Statement A uniform spherical charge density of radius R is centred at origin O. A spherical cavity of radius r and centre P is made. OP = D = R-r. If the electric field inside the cavity at position r is E(r), the correct statement is: 1)E is uniform, its magnitude is independent of r...

Homework Statement In a certain region, the electric potential due to a charge distribution is given by the equation V (x, y, z) = (3x2y2+yz3-2z3x)V0/a4 where a, x, y, and z are measured in meters and V and V0 are in volts. What is the magnitude of the electric field at the position (x, y, z)...

Homework Statement A thin disc, radius 3 cm, has a circular hole of radius 1 cm in the middle. There is a surface charge of -4 esu/##cm^2## on the disc. a) what is the potential at the centre of the hole ? b) An electron starting from rest at centre of the hole moves out along the axis. What...

Homework Statement A line charge with uniform charge distribution and linear charge density ##\lambda## lie along z-axis from ##(0,0,-d)## to ##(0,0,+d)##. Find electric field due to this charge along z, x-axis and potential at ##(0,0,2d)##, ##(\sqrt{3}d, 0,0)## and ##(3d/2, 0 , d)##...

Homework Statement Question : How much charge is stored on the capacitor C2 ? 2. Homework Equations Q = C . U The Attempt at a Solution [/B] Since Q2, the charge stored on the capacitor, is C2 . (Va - Vb) , I thought that I just had to multiply 1.0 x 60 = 60. But in fact, the expected...

From the book, I did not understand, 1. Why does fields coming inwards the sphere contradicts the Gauss law ? 2. I am unable to connect the potential picture and electric field picture. Why does the point P must have lowest or highest potential than neighbouring particles ? 3. I understand...

Hello all, As I understand (and realize when looking at my electricity bill) it seems all power utility company (in residential market) only charge for kW not kVA. But somehow I find it a bit weird when I think about it more deeply. Wouldn't it make more sense to charge for kVA ? Otherwise, it...

To make antimatter you have to change the charge of proton and electron. So how do you do it

Given a charged sphere, the electric field within it is zero at every point. Why is this? Why is not merely zero only at the center? If a sphere is conducting, then its charge is all across the surface. If electric field is inversely proportional to distance from charge squared, won't the field...

Homework Statement A charge ##Q## is distributed unifromly around a thin ring of radius ##b## which lies in ##xy## plane with its centre at the origin. Locate the point on the positive ##z## axis where the electric field is strongest ? Homework Equations The Attempt at a Solution...

Homework Statement Consider a high voltage direct power line which consist of two conductor suspended 3 meters apart. The lines are oppositely charged, If electric field halfway between them is ##15000N/C## how much is the excess positive charge on a 1 km length of positive conductor ...

While reading the book, Electricity and magnetism, the author says that electric field just outside a spherical shell is ##4\pi \sigma##, on it ##4\pi\sigma r_0^2## ,inside is ##0## and outside is ##Q/R^2##. My derivations :- For inside, ##E\Delta S = 4\pi Q = 0## since ##Q = 0##. For...

Suppose a spherical shell is kept at the orgin. Its surface charge density is ##\sigma## and radius is ##R##. I think I remember the formula for its electric potential energy is ##U = \displaystyle {Q^2 \over 2R}##. Now I want to derive it. I used ##\displaystyle U...

Hi, Let's think 2 arbitrary shape conductors with non zero charged. If these 2 conductors are closed, there will be induced charge density over surfaces of these conductors. I have not seen such an example, instead there are lots of problems which involve zero(grounded) potential case and...

It’s been a long time since I took E&M courses and even thought about these things, but a current thread has led me to question the location of excess charge on a conducting shell. Given that there are two surfaces to which charge can move, why doesn’t some charge also locate on the inner...