Coulombs Definition and 115 Threads

The coulomb (symbol: C) is the International System of Units (SI) unit of electric charge. Under the 2019 redefinition of the SI base units, which took effect on 20 May 2019, the coulomb is exactly 1/(1.602176634×10−19) elementary charges. The same number of electrons has the same magnitude but opposite sign of charge, that is, a charge of −1 C.

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  1. G

    How Do I Convert Amps to Coulombs?

    Hi all, I don't feel too confident at the moment to think about this. I have a set of values which I am supposed to work out some thing. The formula I am supposed to use requires me to convert current (Amps) to Charge (C). How do I convert Current to Coulombs? Thanks.
  2. A

    Coulombs Law & Electric Charges

    Homework Statement Two negative electric charges, (Charge A on the left, and Charge B on the right) each with a charge of 3.0 x 10-5 Coulombs are fixed at a distance of 2.9 meters from each other. Find the electric force of charge A on charge B. (Don't forget, if the force points to the left...
  3. T

    How many coulombs of positive charge are in 1.91 mol of O2 gas?

    Homework Statement How many coulombs of positive charge are in 1.91 mol of O2 gas? Homework Equations 1 mol = 6.022x10^23 protons q=Ne The Attempt at a Solution so 1.91 mols x 6.022x10^23 = 1.1502x10^24 protons I divided that by 6.25x10^18 protons in one coulomb, but I got...
  4. H

    Calculating coulombs law in a capacitor?

    Homework Statement Each capacitor has a plate area of 5 inches, with a distance between the plates of 10mm. The capacitor has a total Q of .002 Coulombs. Homework Equations Coulombs law F=Ke X q1q2/r squared The Attempt at a Solution I do not know how to calculate coulombs...
  5. P

    Solving Coulombs Law & Trig via Diagram

    Sorry if I'm doing this wrong... first time poster. Homework Statement The diagram gives the relevant info. All three q's are equal point charges of m=0.10 kg. I'm trying to find the value of q. Homework Equations Coulombs law and basic trig. The Attempt at a Solution...
  6. P

    Equilateral triangle coulombs law problem

    [Homework Statement 1.) Three charges are placed 25 cm apart in an equilateral triangle. Q1 has a charge of -6.0 nC, q2 has a charge of 4.0 nC and q3 has a charge of 4.0 nC. what is the force on q2? q1 is the top point, q2 is the bottom left leaving q3 on the bottom right Homework...
  7. S

    Why is Coulombs Constant Written as 1/(4*pi*epsilon0)?

    q: why we express coulomb constant constant in 1/(4*pi*epsilon0) form rather writing as a constant value 9*10^9 ? why we do not write the value directly as a gravitational constant why 1/(4*pi) came with the constant, we can directly write the exact value. whats the benefit of writing in this...
  8. A

    Coulombs Law solving for electrostatics force

    Homework Statement A small spehere with charge of +6.0uc is located near two other small charged spheres. A -3.0uc sphere is located 4.00 cm to the right and a +1.5uc sphere is located 3.00 cm to the left. Determine the resultant electrostatics force on the 6.0uc sphere. Correct answer is...
  9. F

    When to Use Gauss's Law and Coulomb's Law for Calculating Electric Field?

    When should I use one and when should I use the other? For example, suppose I have a rod of length 2L, with an edge on the point -L on the X axis and another on L. The rod is uniformly charged, with total charge Q>0. having that said, if i wanted to calculate the electric field in an arbitrary...
  10. E

    Rearranging coulombs law equation

    I have just started the physics part of a science foundation course and I am just really struggling how to rearrange equations I have been given a question to rearrange the coulombs law equation as below, to make K the subject and i have been sitting here for hours and i am no further...
  11. T

    Is it A or K? The Debate Over Representing Coulomb's Constant

    I have equation that i have to make A the subject of so the equation is F = A Q1 Q2/r2 this i have done and it becomes A = F x r2/Q1 Q2. the SI units work out as coulombs constant, however on all the web sites i have checked coulombs constant is given as K, even the equations are identical...
  12. D

    Can electric flux be measured in Coulombs?

    Learning electrodynamics here, and the book I'm reading says the following: "By definition, one coulomb of electric charge gives rise to one Coulomb of electric flux, hence Psi = Q (Coulombs)." Yet I'm reasonably certain that flux is not simply charge, and is not measured in Coulombs alone, at...
  13. K

    Coulomb's Law: How to Calculate Electric Force in a Right Triangle

    Coulombs Law--what now? Homework Statement Three point charges are fixed in place in a right triangle. What is the electric force on the q = -0.64 µC charge due to the other two charges? (Let Q1 = +0.71 µC and Q2 = +1.1 µC.) Find: magnitude N and direction ° above the...
  14. B

    Electrostatic force question with coulombs law

    Homework Statement A particle of charge of +4.20 x 10^-6 C is 12.0 cm distant from a second particle of charge of -1.70 x 10^-6 C. Calculate the magnitude of the electrostatic force between the particles. Homework Equations Coulombs law is F = (K*Q1*Q2) / R^2 where k = 8.99*10^9, q1...
  15. C

    Multiple charges and coulombs law

    Homework Statement Two negative charges of -1.0 X 10^-6 C are placed in water and separated by a distance of 0.10 m. A positive charge of 1.0 x 10^-8 C is placed exactly midway between the two negative charges. Determine: a) the electric field( magnitude and direction) and electric...
  16. P

    How Do You Calculate the Charge on Two Suspended Spheres Using Coulomb's Law?

    Homework Statement Two small spheres of 15 g each are suspended from a common point by threads of length 35 cm. Each thread makes an angle with the vertical of 20 degrees. Each sphere carries the same charge. Find the magnitude of this charge. Homework Equations F=(kq1q2)/r^2The Attempt at a...
  17. K

    Coulombs Law Help: Variables Explained

    Can someone tell me the variables in coulomb's law? much appreciated
  18. W

    Using Coulombs Law-Comparative Analysis

    Homework Statement Look back at the Example in the Using Coulombs Law-Comparative Analysis section. Calculate the magnitude of F2 if both changes occurred simultaneously-that is, if the distance between the charges doubled and the size of once tripled, while the size of the other doubled...
  19. W

    Calculating F2 for Double and Triple Changes in Coulombs Law"

    Homework Statement Look back at the Example in the Using Coulombs Law-Comparative Analysis section. Calculate the magnitude of F2 if both changes occurred simultaneously-that is, if the distance between the charges doubled and the size of once tripled, while the size of the other doubled...
  20. J

    Coulombs Law of two metal balls

    Homework Statement Two metal balls A and B of negligible radius are floating at rest on Space Station Freedom between two metal bulkheads, connected by a taut nonconducting thread of length 1.30 m. Ball A carries charge q, and ball B carries charge 2q. Each ball is 1.66 m away from a bulkhead...
  21. N

    Coulombs Law, 4 separate charges.

    Homework Statement the particles have charges q1 = -q2 = 296 nC and q3 = -q4 = 198 nC, and distance between each particle is 5.5cm. Homework Equations Find the net electrostatic force on particle 3 ::Answer is required in vector form <x,y,z>:: The Attempt at a Solution Using...
  22. W

    Calculating Force on q1 using Coulomb's Law | Triangle Diagram

    Three charges are arranged as shown in the diagram below. Their magnitudes are: q1 = +2.5 x 10^-17 C q2 = +3.0 x 10^-17 C q3 = +3.5 x 10^-17 C (its a right angle triangle, with 50 cm as the hypotenuse, 40 cm as the horizontal, and 30 cm as the vertical) sorry i don't have the actual...
  23. B

    How many Coulombs of positive charge are in 1.0 mol of O2 gas?

    Homework Statement Suppose you have 1.0 mol of O2 gas. How many Coulombs of positive charge are in the atomic nuclei of this gas? Homework Equations I assume you would use Q=ne with Avogadro's number... The Attempt at a Solution 1 mol O2/ 6.23 x 10^23 * 8 protons * 1.60 x 10^-19
  24. S

    Coulombs law and vectors, find the force vector

    This is probably really obvious but I have a hard time with vectors and really don't know what it's supposed to look like..I'm not even sure if to draw the grav. force vectors starting from the ends of the ropes or straight down from the centers of the bullets. Homework Statement Two...
  25. A

    Problem involving Coulombs Law; suspended masses

    Two point particles, each of mass m and charge q are suspended from a common point by threads of length L. Each thread makes an angle \theta with the vertical. (I attached a diagram to help). I must show that q=2L\sin\theta\sqrt{\frac{mg}{k}\tan\theta} I start out by writing the force...
  26. K

    Coulombs Law Problem - Find the Force

    Coulombs Law Problem -- Find the Force Homework Statement Two small objects, A and B, are fixed in place and separated by 3 cm in vacuum. Object A has a charge of 2 uC and object B has a change of -2 uC. How many electrons must be removed from A and put onto B to make the electrostatic force...
  27. Y

    Calculate Coulombs Law: Charge, Current, and Power in Electrical Circuits

    Q1. A charge of 4000μC passes each point in a wire in 50s Calculate: a) the charge in coulombs b) The current in the wire c) The number of electrons per second passing each point in the wire (Electron charge = 1.6 * 10^-19 C) Q.2 A 240V kettle transfers 6.9*10^5 joules of energy in 5...
  28. B

    I don't really understand Coulombs Law

    1. How much Coulombs force is exerted on a proton by an electron if they are 15mm away from each other? Is the force attractive or repulsive? 2. http://www.glenbrook.k12.il.us/gbssci/phys/Class/estatics/u8l3b1.gif where k=9* 10^9 N*m^2/c^2 3. I know that the force is...
  29. A

    What is the Net Force on B in an Equilateral Triangle of Point Charges?

    Homework Statement Three identical point charges A, B, and C are located in the shape of an equilateral triangle with sides of length 15 cm. What is the net force on B if each charge has a magnitude of -5.0 x 10-3 C? Homework Equations coulombs law equation The Attempt at a...
  30. O

    Specific charge. Don't understand how to convert to Coulombs

    Homework Statement An ion of a magnesium isotope has A=24 and Z=12. Find the specific charge Homework Equations The Attempt at a Solution I know that the charge of a proton in Coulombs is 1.60\times10^{-19}. From the information given, I know that I have 12 protons and 24-12=12...
  31. R

    Count Coulombs on a Plate: Best Charge Methods

    What is the best way to put a charge on a plate? By 'plate' I mean some mass of conductor surrounded by an insulator. The problem, really, isn't how to generate charge, I know I can use a Van de graff or high-voltage rectifier for that; the problem is that I need to be certain of how much...
  32. P

    Calculating coulombs with 3 charges

    1. A positive charge of 2.6 µC is pulled on by two negative charges. One, -2.0 µC, is 0.050 m to the north and the other, -4.0 µC, is 0.025 m to the south. What total force is exerted on the positive charge? north east south west? 2. I'm using the equation Kq1q2/d^2 k=9E9 q=charge...
  33. R

    How Does Coulomb's Law Apply to a Charge in the Center of a Square?

    Homework Statement four charges aranged on the corners of a square. a fifth charge is located in the middle of the square. what is the net charge on that charge? givens: two charges -5uC are placed at opposite corners of the square, two charges 2uC are placed at opposite corners of the...
  34. C

    How Strong is the Force Between Two Positive Charges?

    Homework Statement What is the magnitude of the force a +15 µC charge exerts on a +2.6 mC charge 41 cm away? Homework Equations F=Ke(Q1*Q2)/d^2 The Attempt at a Solution Well I plugged in the numbers for the variables. Converted 15 and 2.6 to coulombs and 41 to meters. I did the...
  35. O

    Coulombs Law, 3 charges 3 dimensions.

    Homework Statement Homework Equations Fe = (kq1q2)/r^2 The Attempt at a Solution So for part A and B what is the best way to go about doing this? Could I find the distance between the charges and just use coulombs formula?
  36. T

    Electrostatic force including coulombs law

    Homework Statement Of the charge Q initially on a tiny sphere, a portion q is to be transferred to a second, nearby sphere. Both spheres can be treated a particles. For what value of q/Q>0.5 will the electrostatic force between the two parts have 1/2 of the maximum possible value? The...
  37. R

    Calculating Force and Direction of Coulomb's Law Problems

    I'm new in this forum, so i don't know if this is in the correct place.. Homework Statement I got 3 charges q1= 2.0x10^-6C q2=8.0x10^-6C Q=4.0x10^-6C They're placed in the corners of a triangle like in this draw I have to know the force that q1 and q2 act on Q, the magnitude, and the...
  38. K

    Electrostatic Forces and Coulombs Law Question

    Homework Statement Two small, positively charged spheres have a combined charge of 5.4 x 10-5 C. If each sphere is repelled from the other by an electrostatic force of 1.04 N when the spheres are 2.2 m apart, what is the charge on sphere with the smaller charge? Homework Equations...
  39. L

    How Does Coulomb's Law Apply When Socks Repel in a Dryer?

    Homework Statement You remove two socks from a hot dryer and find that they repel with force of 0.002 N when they’re 1 cm apart. If they have equal charges, and you separate the socks until they’re 5 cm apart, what force will each sock exert on the other? Round the answer to 3 significant...
  40. K

    Electric field formula vs coulombs law, contradiction?

    1) between two charged plates, the electric field is given by E=U/d=F/Q->F=QE that means that the force on a particle between these two plates is independant on the position between them. But consider that you have two plates separated by a huge distance, then the force is constant wherever we...
  41. C

    What Are the Units for Coulombs and Volts in Terms of m, kg, and s?

    Im just curious what the units are for coulombs and volts in m kg and s.
  42. Y

    Coulombs law, vectors and charge-HELP

    coulombs law, vectors and charge---HELP! Homework Statement Three positive particles of charges 15.0 µC are located at the corners of an equilateral triangle of side d = 16.5 cm (Fig. 16-38). Calculate the magnitude and direction of the net force on each particle. (Q1 is at the top of the...
  43. Y

    What is the magnitude of the force between two charges using Coulomb's law?

    Homework Statement What is the magnitude of the force a +12 µC charge exerts on a +2.7 mC charge 43 cm away? Homework Equations I know I have to use the equation: F=kq1q2/r^2 The Attempt at a Solution F=(9*10^9)(12)(2.7)/(43^2) =157706868.6 ?right?
  44. E

    Finding the Position and Charge for a Zero Resultant Force in Coulomb's Law

    Homework Statement Three point charges lie along the x axis. A positive charge q1=16.0mC is at x=2.00m. Another positive charge q2=9.00mC is at the origin. Where should we put a third charge so the resultant force acting on it is zero? What should be the sign of the charge? Homework...
  45. V

    How Does Coulomb's Law Determine Force in a Charged Square Configuration?

    Homework Statement A square with side lengths 2.0 cm has a charge of -1.0x10^-6 at every corner. What is the magnitude and direction of electric force on each charge? Homework Equations Fe=kq1q2/r^2 The Attempt at a Solution FeNet=kq1q2/r^2...
  46. P

    Coulombs law and electric fields

    Hey, just wanted to check my method. 1)What is the distance between 2 protons experiencing a mutually repelling force of magnitude 4*10-11? so for this, we have to use the formula for coulombs law--F=kq1q2/r^2 we know F and k. And q1=q2= 1.602*10-19. hence we can find r. 2)Two point...
  47. M

    Why Is Coulomb's Law Not Working in My Calculation?

    Homework Statement A rigid, insulating fiber runs along a portion of the y-axis; the fiber isnot free to move. Gravity acts downward (g = 9.81 m/s2).A charge Qa = -7 µC is fixed to the fiber at the origin. A bead with a hole drilled through its center is slipped over the fiber andis free to...
  48. J

    Where is the zero power point between two positive charges?

    Homework Statement A Positive charge q is between 2 other postive charges Q and 2Q. the distance between Q and 2Q is 1 meter. There is a point on the line between Q and 2Q where the power in the charge q is zero. Where is that point? <--------1 meter-----> +Q---+q-----------+2Q <--d-->...
  49. G

    Can Coulomb's Law Be Rearranged to Solve for Q?

    Coulombs law is F = (1 / (4*pi*epsilon))*((q*Q)/r^2) I want to rearrange this so that Q is the subject. Will I be right in thinking that the equation should read Q = 4*pi*F*epsilon * (r^2/q) Many thanx By the way, what kind of package would I need to import my equations...
  50. W

    Calculating 3.0 Coulombs Per Second in Amps

    Homework Statement What is the value of 3.0 coulobms per second in Amps? The Attempt at a Solution amps are coulombs per second, so its just 3 right? I just want to make sure this isn't some kind of trick. thanks for any input.
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