Charges Definition and 1000 Threads

Homework Statement A particle with charge ##e## and position vector ##\vec{r}## (relative to some frame, S) moves with constant velocity ##\vec{v}##. A second charge ##e'## is moving with the same velocity ##\vec{v}## through the field generated by ##e##. If ##\vec{d}## is a vector from ##e##...

Homework Statement A charge is distributed evenly along the ##z## axis with a density ##\lambda = 3 \frac{\mu C}{m}##. There is also a cylinder with radius ##r = 2## and on his side there is a superficial density charge of ##\sigma = -\left( \frac{1.5}{4 \pi} \right) \frac{\mu C}{m^2}##. Both...

Homework Statement Consider the infinitesimal form of the Lorentz tranformation: ##x^{\mu} \rightarrow x^{\mu}+{\omega^{\mu}}_{\nu}x^{\nu}##. Show that a scalar field transforms as ##\phi(x) \rightarrow \phi'(x) = \phi(x)-{\omega^{\mu}}_{\nu}x^{\nu}\partial_{\mu}\phi(x)## and hence show that...

Homework Statement If linear charge density is equal to 1micro coulomb per meter, then what is the electric field intensity at O? Homework EquationsThe Attempt at a Solution The electric fields due to the two straight lines should cancel out.. But how to progress further? Please let me know...

Homework Statement Two short dipoles each of dipole moment p are placed art origin. The dipole moment of one dipole is along x-axis while that of other is along y axis. Then what will be the electric field at a point (a, 0)?Homework Equations The direction of electric field due to axial dipole...

Homework Statement Two charged metallic spheres of same size repel each other by a force F. They are now touched with each other and are then separated to same initial distance. Now the force of repulsion is F'.Homework Equations On touching the spheres will reduce their charges... So the new...

Two identical small bodies each of mass m and charge q are suspended from two strings each of length l from a fixed point. This whole system is taken into an orbiting artificial then the tension in strings is... The answer has to be kq2/4l but how? Can someone please explain? Plus its not a...

Hi guys. This is my question. I just wondering what equation that I'm suppose to use. Homework Statement What is the maximum distance at which a shark can detect the electric signal emitted by the trout’s heart if the predator is at a point on an axis passing through the centre of the heart...

Homework Statement Hi! How does a charged particle spiral around a magnetic field lines? Is it because the overal magnetic field interracts with the individual magnetic field of the particle? For example if a piece of metal is put inside magnetic field, the electrons will interract with the...

Homework Statement Two particles each with a charge of +3.00 μC are located on the x axis, with one particle at x = -0.80 m, and the other particle at x = +0.80 m. a) Determine the electric potential on the y-axis at the point y = 0.60 m.b) What is the change in electric potential energy...

Homework Statement A positive charge of 3 microCouloumbs is at the origin. A negative charge with the same magnitude is 8 m away along the x direction. a) What are the magnitude and direction of the electric field at the points between the two charges, 2, and 4, and 6m from the positive charge...

Homework Statement An uncharged metal sphere hangs from a nylon thread. When a positively charged, nonconducting glass rod is brought close to the metal sphere, the sphere is drawn toward the rod. But if the sphere touches the rod, the sphere suddenly flies away from the rod. Explain why the...

Homework Statement An object with charge +2.0×10−5 C is moved from position C to position D in the figure (Figure 1) . q1 = q3 = +10.0×10−5 C and q2 = −20.0×10−5 C. All four charged objects are the system. Here's a picture to the problem Homework Equations $$ F = \frac {kq_1 q_2}{r^2} $$ $$...

Homework Statement Three equal charges with charge q and mass m are placed into an equilateral triangle of side length L. Find the speed of each when they are infinitely far from one another. Homework Equations -ΔU =ΔK (since the electric force is conservative), U= 1/4πε Σq1q2 /r The...

Homework Statement Two uniform masses of .260kg are fixed at points A and B. Find the magnitude and direction of the initial acceleration of a uniform sphere with mass 0.01kg released from rest at point P that is acted on the gravitational forces of attraction from spheres A and B. The diagram...

Homework Statement Please refer to the image; problem-1. My theory is that there are two spheres 'A' and 'B', where 'A' is (partially and primarily) positively charged, and 'B' is (partially and primarily) negatively charged. The magnitude of negative charge is greater than the positive charge...

(Sorry my poor English) A changing electric field creates a magnetic field and vice-versa. I thought one field were created only when the another field were disturbed and it works finely for electromagnetic waves, and it agrees with Maxwell's equations. I was happy with my conclusion then I...

Homework Statement Three electrons form an equilateral triangle 0.800 nm on each side. A proton is at the center of the triangle. Homework Equations U = k[(q_1*q_2)/r] The Attempt at a Solution I tried to use the following equation: k*[(3e^2)/(0.8*10^-9) - (3e^2)/(0.4*10^-9)] I plugged in...

Homework Statement The point charges in the figure have the following values: q1=+2.1μC, q2=+6.3μC, q3=−0.89μC. Suppose that the magnitude of the net electrostatic force exerted on the point charge q2 in the figure is 0.57 N . Find the distance d and the direction (angle) of the net force...

Homework Statement Homework Equations |E| = (Kq)/r^2 The Attempt at a Solution I'm not really sure if there is a difference between part (a) and part (b)

Homework Statement In the figure the four particles form a square of edge length a = 6.10 cm and have charges q1 = 6.35 nC, q2 = -17.9 nC, q3 = 17.9 nC, and q4 = -6.35 nC. What is the magnitude of the net electric field produced by the particles at the square's center? Homework Equations...

Are there any particles known in the Physics world with an either positive or negative charge that can be viewed by the human eye under LED light illumination and have an attraction/repulsion to magnetism?

Does anyone have a formula and derivation of the force between two charges in the presence of two dielectric media. Specifically, have the two dielectric media separated by a plane at z = 0. I have a developed a solution using image charges to matched the boundary conditions at the dielectric...

There is charge ##q_0## which is fixed.from a distance far away another charge ##q_1## is fired towards it with speed ##V_0## then we know as both of these are positive charges these will repel each other as the charge ##q_1## comes closer. While coming closer to ##q_0##, it's speed decreases...

The book I'm reading is discussing the physics of semiconductors. I'm having a hard time understanding a passage in section introducing n-type semiconductors. (Phosphorus is used as the impurity) The book says: "At normal operating temperatures, this extra electron breaks its bond with the...

Homework Statement A charge (q) is placed in-between two other equal charges named Q. Q-----q-----Q a) If both Q's are positive, is charge q in equilibrium? If yes, is it a stable or unstable equilibrium? b) What about if one Q is negative while the other is...

Homework Statement Hello. I am having trouble understanding this particular statement found in one of my textbooks. " Work done to move a charge along a line perpendicular to the field is zero" The Attempt at a Solution Field is a space around a charge where if we place any other charge...

When a capacitor is connected to battery then positive charge is induced on one plate and a negative charge is induced on another plate.Now what happens to the charges that are induced on opposite sides of each plate i.e. on plate with positive charge a negative charge would be induced on...

Homework Statement IF the resultant electric field at D due to the three point charges is zero, find the magnitudes of q1 q2 in terms of q [/B]...

Homework Statement Q If an object having charge 'q' is brought near an uncharged conductor (sphere) , would the charge induced on the nearby surface ( closer to the charged object ) be equal to '-q' ? Homework EquationsThe Attempt at a Solution I think the charge induced would be less than...

Homework Statement If there is an uncharged metal spherical body and a charge q outside it .Find Electric field due to induced charges. Homework Equations ##E##=##\frac{Kq}{r^2}## The Attempt at a Solution If there is an uncharged metal spherical body and a charge q outside it then there will...

Homework Statement There are three point charges inside a conducting spherical shell of radius R. One of them of charge -2q is in the origin and the other two with charge q are in z=d and z=-d. Find the potential inside the sphere! Homework Equations ##\nabla^2\phi=4\pi \rho## 3. The attempt...

Homework Statement I'm having a bit of trouble evaluating the following commutator $$ \left[T^{+},T^{-}\right] $$ where T^{+}=\int_{M}d^{3}x\:\bar{\nu}_{L}\gamma^{0}e_{L}=\int_{M}d^{3}x\:\nu_{L}^{\dagger}e_{L} and...

Hello. I am an intro Physics student and this is my first post here. In Coulomb's law the charges are said to be stationary. I need some clarification about what does it mean for two charges to be stationary: A. Does it mean that the charges are not moving with respect to each other? (But...

Find the force on 2Q and -Q/22. Force between two point charges is given by : F = k.q1.q2 / d[2][/SUP]The Attempt at a Solution To find the force on 2q, I added the charges on left side and then calculated it using the formula. But how do we do it for -Q/2. Please guide me. Thanks

Homework Statement Consider two solid dielectric spheres of radius ##a## separated by a dis- tance ##R## (##R\gg a##). One of the spheres has a charge ##q## and the other is neutral. We scale up the linear dimensions of the system by a factor of two. How much charge should reside on the first...

Homework Statement The Attempt at a Solution Now, they're in series, so I found the equivalent capacitance to be about 0.57 microFarad. And I have technically gotten the correct answer according to the back of the text. The question in the text clearly asks for the charge on each...

Figure (a)shows two concentric conducting shells .Some charge Q1 is given to the outer shell.No charge is developed on the inner shell.I want to know why?When charge is on inner sphere ,charges also develop on outer shell then why not charge develops on inner shell when there are charges on...

i can't seem to get a handle on this...help :)

Are there any particles which have a neutral electrical charge and are not affected by the weak or strong nuclear force? Thank you for your time and please excuse me if I'm being very ignorant!

Homework Statement Homework EquationsThe Attempt at a Solution the answer for d comes out to be 0.017 m. BUT, if we kept with tan instead of switching to sin, we would have mg(d/2)/ mg =kq q / d2 d^3 = 2k q q solving for d d = 0.0121 m clearly on a big scale, the two answers are about...

Homework Statement A triangle is given with the points: Q1 = +2.0 x 10-5 C 2.0 m from Q3 = -3.0 x 10-5 C AND Q1 = +2.0 x 10-5 C 2.0 m from Q2 = -3.0 x 10-5 CThe triangle is a right triangle, with Q1 at the 90 degree angle.FIND THE NET FORCE OF CHARGE 1Homework Equations [/B] FE21 = FE31...

I am not able to understand electric currents. Can anyone explain?

At the outset, I want to explain that this is a problem I came up with myself. It's not actually homework, and I suspect it is deeply conceptually flawed in some manner that I have yet to determine. 1. Two point charges of like polarity, ## q_1 = q_2 = 1C ##, start out separated by distance ##...

Homework Statement 1. Compute the electric field vector at the position of charge B for the case where q_{A}=4q_{C} and r_{1}=2r_{2} 2. Suppose that all three charge are positive and that q_{A}=4q_{C} . Consider the case where f q_{B} is moved to the right by a distance dr. Now r_{1} = 2r+dr...

Hi, I am learning about the method of image charges, but am struggling to sufficiently justify my answer. It appears to be correct, though it quite possibly isn't... 1. Homework Statement (please see attached item) Two semi-infinite grounded conducting planes (the shaded region in the...

How to find potential ENERGY between two point charges?I know how to find potential difference between two points and I also know how to find potential at any point . potential difference between two points 1 and 2 is simply ##V1##-##V2## potential at any point r=V While source charge is Q...

Homework Statement I need to solve a bit of a simple "reverse" problem that I'm unable to find treated in any detail, probably because it's actually reasonably straightforward. What I need to do is to "compute the charge and current distribution that give rise to [the following] field."...

Hello, So, I know quarks are confined in baryons. In a proton, there are "3" quarks, but the sum of their masses is not the mass of the proton. This implies a major fraction of the proton mass comes from interactions. My question is, how then do they measure quark u and d masses? And...

Homework Statement Consider the figure below, we need to find the charge on Q_0, both charges Q are negative. It is given that the net charge on Q_A is zero. The figure of the problem is attached. The Attempt at a Solution I understand how to get the solution except for one part. I'm just...