Electric fields Definition and 507 Threads

I'm an HVAC engineer and my company has tasked me with researching a variety of water treatment products (for cooling towers). One of which is Dolphin Water Care (http://www.dolphinwatercare.com/Index.aspx) The technology seems a little fishy to me, so I wanted to see if anyone could tell me...

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. I don't understand...

Homework Statement *ignore the given numbers in the image, mine is different* My numbers are: Q1: 1nC Q2: 8nC Q3: -6nC Homework Equations E = \frac{kq}{r^2} * \hat{r} The Attempt at a Solution I only did (a1) so far. I know (a2) involves the exact...

Homework Statement Field Lines Three Figure 23-64 shows the electric field lines for three point charges separated by a small distance. The two outer charges are identical and the one in the center is different. Figure 23-64 (a) Determine the ratio, qA / qB, of one of the outer charges...

1. Homework Statement In a laboratory, a particle of charge -6C is held stationary because it is placed in an electric field E=(0,0,-15)N/C which suspends it against gravity. What is the mass of the particle? Give answer in kg. 2. Homework Equations I THINK E= F/q F= ma or F= G m1 m2 /...

Is there any effects on electric fields or magnetic fields in a Gravitational field? I know that electro-magnetic waves(photons) are effected from the bending of space and time, from gravity. however i was just wondering how magnetic fields or virtual photons respond to gravity. Any...

I was having some trouble understanding how an electric dipole creates an electric field around it? Shouldn't the two oppositely charged particles in the dipole totally cancel out their electric fields? Well, I figured out that the two particles only exert a force on each other...

Homework Statement Would it be possible for someone to check my answer to this past examination question, as I am not sure I'm doing them correctly! Thanks in advance. A negatively charged oil drop, mass 2.4 x 10^–12 kg, is stationary between two horizontal metal plates spaced 1 cm apart...

This is a question that I'm doing as part of revision for my January mocks. Being bad a algebra in general, I'm stuck. The answer is a worked example and I still don't understand it, so I'm feeling very silly. Homework Statement Charges of +4C and +8C are placed 1.00m apart. At what...

Hello, First of all, I'm not sure if this is in the right section, and I know it's probably a very basic question compared to all you levels of knowledge. So please if it isn't in the right section, let me know where I should post it, and if not thanks in advance for the help. I'm trying...

I can understand that in the middle of an empty conductor sphere the electric field is worth 0. But I don't understand why it is also 0 in the interior of the sphere at any point. I know that by Gauss' law it is 0 but I don't grasp it. For instance if you chose a point very close to the...

why is there a different equation for force in a uniformed electric field F=E/Q as opposed to the electric field between a pair of oppositely charged plates F=EQ ? I thought it would be the same as the field between a pair of oppositely charged plates are also relatively uniformed, in the...

Homework Statement A sphere of radius R=10 cm made of insulating material has a uniform charge density p=100 C/m-3 a)Find the magnitude of the electrical field at a distance r<R, using Gauss' Law.What is the value of the electric field at r=5 cm? b)What is the total charge on this...

Im curious about an electric field (somewhere of radius s) inside a solid sphere (radius a) such that: \int E.da=E4\pi s^{2} and Q = \frac{\rho 4\pi s^{3}}{\epsilon_{o}3} What is the difference between using each coordinate system to solve for E? It's just that I've really had to teach...

Homework Statement A long solenoid has a diameter of 12.0 cm. When a current i exists in its windings, a uniform magnetic field = 25.0 mT is produced in its interior. By decreasing i, the field is caused to decrease at the rate of 6.30 mT/s. Calculate the magnitude of the induced electric...

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...

Electric fields and "Frozen charges" Homework Statement A large parallel plate capacitor is charged at first and creates a uniform electric field inside which is to the right and of magnitued E0. Then a small metal box is inserted inside the capacitor; small means that the insertion does not...

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...