Electric fields Definition and 483 Threads

Homework Statement By considering the centripetal force which acts on a planet in a circular orbit, show that T^2 is proportional to R~^3 where T is the time taken for one orbit around the sun and R is the radius of the orbit Homework Equations I'm thinking keplers third law? The...

Homework Statement This is from a lab program for my class. Its set on a grid where I can place charges and use the mouse pointer to find the intensity of the field at any spot. I am using the E values I got from hovering my mouse over the indicated spot (x, y). I have a positive 10...

Homework Statement Integration I am soooo lost. I don't even know if this is the right forum... But where is the bridge between Calculus and Physics? I can Integrate equations, but when it comes to physics, i for one, don't know when to integrate; two, i don't see how you find the constants...

Homework Statement Ok, here's the problem. It deals with the superposition of electric fields from uniformly charged shapes: A uniformly charged infinite plane is located at z = 0, with a surface density of charge σ. A uniformly charged spherical shell with the same surface density is located...

Homework Statement Our lab is not online, but this is so similar to what we did. http://physics.fullerton.edu/~SAM/PDF/Lab%20Manuals/212/Individual%20Experiments/Equipotential%20Surfaces%20E6.pdf" Instead of the ten that they set their voltage to, we set ours to 12. Homework Equations...

Homework Statement The figure below shows two concentric rings, of radii R and R ' = 3.00R, that lie on the same plane. Point P lies on the central z axis, at distance D = 2.00R from the center of the rings. The smaller ring has uniformly distributed charge +Q. What must be the uniformly...

Ok I have a general question. Say I have a bunch of electrons moving in a line, not in a wire, but I guess it could be looked at as if it was in a wire. This is my question: So if i picked a point outside of this line of moving electrons, would I find an electric field? I know that...

Homework Statement If electric fields are perpendicular to the equipotential surface, what is the orientation of the field on the surface of a conductor (like metal)? Why is this so? Homework Equations E= ∆V/d The Attempt at a Solution I know that there is no charge within a...

Homework Statement An electric field is given by E_x = (5 kN/C) x^3. Find the potential difference between the points on the x-axis at x= 1 m and x = 5 m. Answer in units of kV.Homework Equations V = -EdThe Attempt at a Solution V1 = -5*10^6 N/C * 1 = -5*10^6 volts V2 = -5*10^6 * 5 = -25*10^6...

Homework Statement A point charge +Q is placed at one of the corners of a cube as shown in the figure.The electric flux through the surface ABCD of the cube due to the charge is (1) Q (or Q/\epsilon_{0}) (2) Q/4 (or Q/4\epsilon_{0}) (3) Q/6 (or Q/6\epsilon_{0}) (4) Q/24 (or...

Homework Statement ABCD are 2 parallel plates,between which a potential difference of 10,000V is maintained.An electron starting from rest,from point P,moves towards a small hole at Q. After emerging from Q,the electron passes through a region independent of any electric fields and then...

A particle with charge +7.88 μC is placed at the fixed position x = 3.00 m in an electric field of uniform strength 300 N/C, directed in the positive x direction. Find the position on the x-axis where the electric field strength of the resulting configuration is zero. the equation i have is...

Homework Statement Suppose you want to determine the electric field in a certain region of space. You have a small object of known charge, and in an instrument that measures magnitude and direction of the force exerted by object by the field. (a) The object has a charge of +20.0 C, and...

Sorry if i have posted under the wrong catagorie physics is new to me so I am still getting my head around it. Here is the question that is giving me a bit of bother; An airplane is flying through a thunder cloud at an altitude of 2km. If the cloud has a charge concentration of 40C at an...

Homework Statement An electron is accelerated from the filament in a vacuum tube towards a metal grid which is maintained at a potential of 180 Volts. It goes through one of the holes in the grid and continues towards a metal plate 1.2 cm away which is maintained at a potential of -10.0 Volts...

There are no electric fields outside of a charged capacitor as they are canceled out due to superposition, right?! So why is there a flow of current when a cable is connected to both ends of the capacitor? I was told that there might be an E field in the wires. How come? Where does it come from?

Just a few brief questions that my teacher did not answer during the last class: 1) Why is the potential difference at any point inside a charged conducting sphere the same? 2) If a charge were placed outside of a charged say, conducting cube, would the electic field drop off...

Homework Statement 1. Oersted discovered that a curernt carrying wire caused a magnet to move. Why does the magnet move? 2. Ampere discovered that a magnet caused a current carrying wire to move. Why does the wire move? Homework Equations (i) ∫Edl = - dΦ_B/dt (ii) ∫Bdl = Iμ_0 +...

Homework Statement The x-y plane contains point charge with magnitudes and positions as follows: A charge of Q lies at co-ordinates (0, a) A charge of -Q lies at co-ordinates (0,-a) Show that the magnitude of the electric field at (b, 0) is given by E = Qa / [2πε0(a²+b²)^(3/2)]...

Homework Statement Two negative charges of -1.0x10^-6 C each are placed in water and separated by a distance of 0.10m. A positive charge of 1.0x10^-8 C is placed exactly midway between the two negative charges. Determine: a) the electric field (magnitude and direction) and electric...

You've hung two very large sheets of plastic facing each other with distance d between them . By rubbing them with wool and silk, you've managed to give one sheet a uniform surface charge density n1=-n0 and the other a uniform surface charge density n2=3n0 . Homework Statement Find the...

Homework Statement An electron enters a parallel plate apparatus 10cm long and 2.0cm wide, moving horizontally at 8.0 x 10^7 m/s. If the potential difference acrros the plates is 600V: a) the vertical deflection of the electron from its original path. b) the velocity with which it...

An electric field causes the 5.0 g point charge to hang at a 20 angle. What is the charge of the ball I don't have the figure but it looks like a simple pendulum hanging at the angle of 20 degree Homework Statement E= 100,000 N/C m of the ball = 5g Angle =20 degree e0= 8.85*10^12...

Homework Statement An electron travels with v= 5.90(10)^{6} i through a point in space where E=<2.30 (10)^{5} i, -2.30(10)^{5} j> and B = <-0.200 k> Homework Equations F=q(E+(v x B) The Attempt at a Solution I did q of the electron equals 1.6(10)^-19 the with v x B = -.2k...

Homework Statement Living cells actively “pump” positive sodium ions (Na+) from inside the cell to outside the cell. It’s called pumping because it requires work to move the ions from the negatively charged inner surface of the cell membrane to the positively charged outer surface. It...

Physics Mutiple Choice Problems! Please help and explain why. Thank you :) 1. Which of the following statements is true concerning the spacing of the electric field lines in the vicinity of two point charges of equal magnitude and equal sign? A It indicates the relative magnitude of the...

Homework Statement Find the electric field and the potential at the center of a square 2.0 cm with charges of +9.0uC at one corner of the square and with charger of -3.0uC at the remaining 3 corners. Homework Equations the sum of Vi= the sum of KQi/ri The Attempt at a Solution I...

I need a lot of help with Coulomb's Law and Electric Fields?? Need HELP! Homework Statement Here are 3 of the 25 questions the i did not understand, in regards with electric fields and Coulomb's Law. 1. A small object of mass 2.0 g and charge of 1.8x10^-7 C "floats" in an electric field...

Homework Statement If the magnetic field lines held within a closed path are constant and unchanging, will there be an electric field along the closed path? Homework Equations there are none. The Attempt at a Solution No. If it is unchanging, then no electrical energy will be...

Homework Statement Four charges are arranged in a square. 2 Positive and 2 negative, in opposite corners. The magnitude is |1.6x10^-6 C|. The square's sides are 1 cm. A] At point X (Midpoint of of one of the sides. See Picture) Find the electric field direction and magnitude. B] What is the...

Homework Statement A particle with charge +7.88 μC is placed at the fixed position x = 3.00 m in an electric field of uniform strength 300 N/C, directed in the positive x direction. Find the position on the x-axis where the electric field strength of the resulting configuration is zero...

Homework Statement 3. Four charged particles are held fixed at the corners of a square of side s. All the charges have the same magnitude Q, but two are positive and two are negative. In Arrangement 1, shown , charges of the same sign are at opposite corners. Express...

Homework Statement The figure below shows a test charge q between the two positive charges. Find the force (in Newtons) on the test charge for q = -4 µC. a)Give a positive answer if the force is to the right and a negative answer if the force is to the left. b.)For the previous question...

Homework Statement Use Coulomb's law to determine the magnitude and direction of the electric field at points A and B in Fig. 16-57 due to the two positive charges (Q = 4.0 µC) shown. The Attempt at a Solution Basically, I'm completely lost. I've applied Coulomb's law to find the...

Homework Statement Two particles with positive charges q1 and q2 are separated by a distance s. Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero. Homework Equations E= \frac{kq}{r^2} The Attempt at a...

Homework Statement At a particular moment, three small charged balls, one negative and two positive,are located as shown in Figure 13.46. Q1 = 1 nC, Q2 = 5 nC, and Q3 = -2 nC. Remember that you must first convert all quantities to S.I. units. 1 nC = 1 nanocoulomb = 1e-9 C. (a1)...

Homework Statement three point charges are placed at the following points on the x-axis +2 uC at x=0, -3uC at x=40 cm, -5 uC at x=120 cm. find the force (a) on the -3 uC charge, (b) on the -5 uC charge ans. (a) -0.55N ; (b) 0.15 N uC=nano coulomb Homework Equations Fm=qvB ...

Homework Statement An air-filled capacitor consists of a conducting sphere of radius a, surrounded by a concentric conducting spherical surface of radius b. A charge of 2Q is placed on the inner sphere and –Q on the outer surface. Calculate the electric field strengths E(r), (i) between the...

So if the electrocstatic force and electric field can be different directions which direction would a particle go? Would it depend on the field or the force, or something else like potential difference?

Can somone please explain why the following is not true: "Electric potential is zero whenever the electric field strength is zero" I know that the Field strength is the potential gradient, however why is the above true? Thanks in advance

Homework Statement A proton (m=1.67x10^-27) is suspended at rest in a uniform electric field E. Take into account gravity and determine E. Homework Equations FE=|q|E Fg=mg The Attempt at a Solution FG = mg FG = (1.67x10-27)(9.8) FG = 1.64 x 10-26 Since the force on the...

I'm being taught electromagnetism at university, but there's one definition that has been left slightly ambiguous for an electric field to be conservative I've been taught that 1) \nablaxE = 0 But I've also been taught that 2) \oint E.dl = 0 But I am not sure if 1) & 2) have to be true...

Multiple Point Charges Alright so the question is: A charge of 1.2x10^-3C is fixed at each corner of a rectangle that is 30cm wide and 40cm long. What is the magnitude and direction of the electric force on each charge? What is the electric field and the electric potential at the centre? I...

If anyone would like a go at this problem, they can just attach a paint file or something or send it to my e-mail: Heres the problem: 9. Three small, negatively charged spheres are located at the vertical of an equilateral triangle. If the magnitudes of the charges are equal, sketch the...

Homework Statement I have three questions concerning the electric field: 1- When calculating an electric flux for a spherical charge distribution my proffessor always writes "4 pi r2 E(r) = flux", where E(r) is the electric field. I don't understand this. I've tried to calculate the...

THe following is a homework assignment from AP Physics. Homework Statement Two large, flat parallel conducting plates are .10m apart. THe lower plate has a Voltage of 10v while the upper plate has a voltage of 20V. Point P is located .04m from the bottom plate. Find: a) THe magnitude of the...

What makes the electric field uniform? I learned it as a field that doesn't vary from place to place, but I'm trying to understand that better conceptually. For example, for problem #6 on the multiple choice http://www.enc.edu/~john.u.free/PY%20202%202006-7/Resources/Exam_1_05-06.htm...

Hi, I'd like to ask the good people of this forum for some help. Here's a problem I've been working on for a while, and I'm seriously at my wit's end. I guess there's something I'm missing here... Homework Statement Two insulating spheres have radii r[SIZE="1"]1 and r[SIZE="1"]2, masses...

Homework Statement So the question states: Four point charges, each of magnitude q, are located at the corners of a square with sides of length a. Two of the charges are +q and two are -q. The charges are arranged in one of the following two ways: (1) The charges alternate in sign...

A figure showing electric field lines has two charges, q and -q. There are 24 lines emanating from the +q charge. 15 of these lines terminate at -q. There are 24 lines terminating at the q- charge. What is the net flux through the surface surrounding the two charges?