What is Electric forces: Definition and 69 Discussions

An electric field (sometimes E-field) is the physical field that surrounds electrically-charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field for a system of charged particles. Electric fields originate from electric charges, or from time-varying magnetic fields. Electric fields and magnetic fields are both manifestations of the electromagnetic force, one of the four fundamental forces (or interactions) of nature.
Electric fields are important in many areas of physics, and are exploited practically in electrical technology. In atomic physics and chemistry, for instance, the electric field is the attractive force holding the atomic nucleus and electrons together in atoms. It is also the force responsible for chemical bonding between atoms that result in molecules.
Other applications of electric fields include motion detection via electric field proximity sensing and an increasing number of diagnostic and therapeutic medical uses.
The electric field is defined mathematically as a vector field that associates to each point in space the (electrostatic or Coulomb) force per unit of charge exerted on an infinitesimal positive test charge at rest at that point. The derived SI units for the electric field are volts per meter (V/m), exactly equivalent to newtons per coulomb (N/C).

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  1. F

    Electric Forces; Coloumb's Law question

    Homework Statement three spheres, each with a negative charge of 4.0 X 10^-6 C, are at the vertices of an equilateral triangle whose sides are 0.20m long. Calculate the magnitude and direction of the net electric force on each sphere. Homework Equations Fe= kq1q2/r^2, where k is the...
  2. C

    Calculating Electric Forces with Dangling Objects

    How do I calculate Electric forces when objects are dangling from insulated wire. For example Neutral metal sphere A, of mass 0.10kg hangs from an insulating wire 2.0m long. An identical metal sphere B, with charge -q, is brough into contact with the sphere A. The spheres repel and stelle down...
  3. H

    Electric Forces and Electric Fields of a proton

    Hi, I am currently stuck on the following questions. Any help is greatly appreciated. thank you *all question are algebra based 1) A point charge of -0.90 microC is fixed to one corner of a square. An identical charge is fixed to the diagonally opposite corner. A point charge q is fixed to...
  4. R

    What force is lifting the weight on the bottom wire and how was it created?

    There are two long horizontal wires. The currents in both wires are traveling in the same direction. The current in the top wire is much larger than the current in the bottom wire. A weight is suspended from the bottom wire. Since magnetic forces can't do work, what force is doing work on...
  5. L

    Determining the Net Charge on a Suspended Ball in an Electric Field

    a small 2 g ball is suspended by a 20 cm string in a uniform electric field of 1.0 x 10 to the fourth power N/C. If the ball is in equilibrium when the string makes a 15 degree angle with the vertical, what is the net charge on the ball? I need someone to check my work for me F=mg (mass...
  6. J

    How can I represent electric forces on a system with 3 charged balls?

    I have an illustration that look like this: - + + on top of a cart. The charges are balls and are very light, and have equal maginitude charge. The rods supporting and connecting them are made with an insulating material and are also light. The cart rests on a smooth table. How would I draw...
  7. D

    Find Electric Force Using Mass, Gravity & Angle

    I have quiz coming up soon, and my teacher hinted that I had to find a formula for electric force using variables of mass, gravity, and an angle. "Fe" = eletric force, |E| = field strengh, q= charge in Columbs. To find eletric force all i know is Fe = kq1q2/r^2 , Fe = |E|q anyone got...
  8. S

    Electric forces and electric fields

    for the pentagon, there is a + charge at 1, - @2, - @3, + @4, - @5, and + @6. In part A, we are asled to find the net electric field at point P, which is half way between 1 and 2. Each side is 2 mm long, and each charge is an elemental charge. So, I did- E1=E2=kq/(r^2)...for r I used...
  9. P

    How do I add all the electric forces acting on charged particles in a square?

    Electric Forces Problem need help! ok i need to kno how to add all the forces acting on charged particles. these particles are in a square + . - . -. - . for instance i solved for all the forces acting on the + particle but i don't know how to add the three since it adds one...
  10. N

    Calculating Electric Force on Charges of 2.0 uC

    Ok, the problem states: there are four charges, each with a magnitude of 2.0 uC. Two are positive and two are negative. The charges are fixed to the corners of a 0.30 m square, one to a corner, in such a way that the net force on any charge is directed toward the center of the square. Find...
  11. C

    What is the Ratio of y/x for Zero Net Electric Force on a Charge?

    Hello all. I am kindof stuck on this problem. It asks: The figure below shows three point charges all posotive. If the net electric force on the center charge is zero, what is the value of y/x. The answers: a) 4/9 b) \sqrt{2/3} c) \sqrt{3/2} d) 3/2 e) 9/4 This is my figuring...
  12. L

    Homework help - Electric forces

    Homework help -- Electric forces "Two tiny water drops, with identical charges -1.00x10^16C, have a centre to centre spereration of 1.00cm. A) What is the magnitude of the electrostatic force acting between them? B)How many excess electrons are on each drop, giving it its charge imbalance?"...
  13. N

    Kinematics with electric forces

    forgot this formula Here is the question: determine the vertical component of its velocity after it has traveled a certain distance horizontally... does any1 remember the formula thanks
  14. N

    How Do Electric Fields Interact at Specific Points on the Y-Axis?

    Two 2.06e-6 C point charges are located on the x axis. One is at 1.06 M and the other is at -1.06 M (a) Determine the electric field on the y-axis at .48 M This is how i did it: Etotal=sum of E vectors... E=ke*q/r^2 r^2=1.06^2+.48^2 q=2.06e-6 E1 = Ke*q/(1.06^2+.48^2) E2=...
  15. M

    Relationship between electric forces

    I am wondering if there is some way for the force between two charges (calculated by Coloumb's law) and the force applied by a field on a charge. Thanks in advance
  16. D

    Can someone help a newbie, electric forces

    Ok this is the question in textbook i can't figure out. "The force of repulsion that two like charges exert on each other is 3.5N. What will the force be of the distance between the charges is increased to fice times its orginal value ? " im a physics moron , treat me like one :smile...
  17. S

    Problem driving me insane electric forces

    When 2 identical ions are separated by a distance of 3.3*10-10m, the electrostatic force each exerts on the other is 8.5*10^-9N. How many electrons are missing from each ion? I know I have to use coloumb's law to get Q1Q2, but how do i get the number of electrons missing from each?
  18. D

    Electric Forces and Electric Fields in DNA

    I need help with the following, I don’t even know how to start A molecule of DNA ( deoxyribonucleic acid) is 2.17μm long. The ends of the molecule become singly ionized – negative on one end, positive on the other. The helical molecule acts as a spring and compresses 1.00 % on becoming...
  19. Z

    Electric Forces and Electric Fields

    Hello all, Physics is generally pretty hard for me, so understanding Electric forces has been a monster. I've done what I "know" how to do on the following problem, but I need some input from the professionals =) Thank you in advance. Two point charges, Q1 and Q2 are located a distance .20...
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