Definition of the electric field. Electric field near a point charge.
Log in rajeshk9925 7 years agoPosted 7 years ago. Direct link to rajeshk9925's post “Why electric feild is mor...” Why electric feild is more stronger then magnetic field and gravitational field ? • (10 votes) APDahlen 7 years agoPosted 7 years ago. Direct link to APDahlen's post “Hello Rajeshk,This is a...” Hello Rajeshk, This is an unsatisfying answer but it just is... These are fundamental forces of nature. As a consolation for my poor answer may I share my favorite video on the topic: https://www.youtube.com/watch?v=1TKSfAkWWN0 Enjoy, Aaron (16 votes) dena escot 2 years agoPosted 2 years ago. Direct link to dena escot's post “what is meant by "If char...” what is meant by "If charges are smeared out in a continuous distribution, the summation evolves into an integral."? • (3 votes) Willy McAllister 2 years agoPosted 2 years ago. Direct link to Willy McAllister's post “There are two ways to thi...” There are two ways to think about charge. We know that charge is the property of two atomic particles, electrons and protons. This makes it convenient to think about charge as particles, or like a bunch of sand. You can count sand particles (if there are not too many). Coulomb's Law treats charge this way, there's a q1 and a q2. Another way is to think of charge as a continuous substance, like peanut butter. Peanut butter isn't a collection of particles, it's something different. You charge something by slathering it with peanut butter charge. The charge is uniformly distributed throughout the peanut butter. If you are presented with a problem based on peanut butter charge you have to figure how to apply particle-based Coulomb's Law. In this blob of charge we have to somehow identify a charge particle. The trick is to use calculus to focus down on a tiny tiny bit of the charged structure, a bit so small it can be considered a particle. So in the article you see the equation for the electric field from multiple charges F = 1/4pieo SUM (q_i/r^2) In peanut butter charge q_i becomes the differential charge dq, and the SUM turns into (evolves into) an INT (integral). F = 1/4pieo INT (dq/r^2) These two equations mean the same thing. In the second we rely on calculus notation to do the bookkeeping for adding up all those infinitesimal dq's. Shivaprasaath 7 years agoPosted 7 years ago. Direct link to Shivaprasaath's post “What is an equatorial lin...” What is an equatorial line? • (3 votes) Willy McAllister 7 years agoPosted 7 years ago. Direct link to Willy McAllister's post “That's a line around the ...” That's a line around the equator of an object. You are probably looking at a problem that includes a sphere, and the sphere has an obvious "up" and "down" axis. The equator is the line half way between the north and south poles of the sphere, just like the Earth. (7 votes) fahim ab 8 years agoPosted 8 years ago. Direct link to fahim ab's post “Sir i'm not saying about ...” Sir i'm not saying about electric field strength or intensity.I am asking that can we measure how much area an electric field surrounds.?or it is spread to infinity? • (2 votes) karl.birkir.f 8 years agoPosted 8 years ago. Direct link to karl.birkir.f's post “The strength of the elect...” The strength of the electric field weakens with the square of the distance. So if you double the distance it's only 1/4th of the strength, if you increase the distance ten-fold the strength becomes 1/100th, and so on. Much the same as gravity. So, while it might not be "cut off" at a certain point it obviously diminishes quite fast into trivial strengths. Perhaps we could view it as being "cut-off" when the strength goes below Planck sizes. (7 votes) Kirill Khazan 7 years agoPosted 7 years ago. Direct link to Kirill Khazan's post “In the denominator of the...” In the denominator of the equation given in "Electric field near multiple point charges", what is r? Considering we sum over multiple point charges, and our point might not be equidistant from all of them, shouldn't it be r_i? • (2 votes) Willy McAllister 7 years agoPosted 7 years ago. Direct link to Willy McAllister's post “You are correct. The r in...” You are correct. The r in the denominator should probably have a subscript of i. (5 votes) sairoshanpatra 10 months agoPosted 10 months ago. Direct link to sairoshanpatra's post “electric field is also wr...” electric field is also written in volts/metre. how is it similar to newtons/coulomb and why is volts/metre appropriate. • (2 votes) Willy McAllister 10 months agoPosted 10 months ago. Direct link to Willy McAllister's post “The two representations f...” The two representations for electric field are "equivalent", meaning you can derive one from the other. The volt is the unit of electric potential, which is energy (joules) per unit charge (coulombs). That means 1 volt is a nickname for a potential of 1 joule/coulomb. One joule of energy is the energy required to accelerate a mass of one kilogram using one newton of force over a distance of one meter. The newton is the unit of force and has units of F = ma or kg*m/sec^2. So, 1 newton of force is 1 joule of energy applied over 1 meter, or 1 joule/meter. Imagine you are measuring electric field in the air gap between two capacitor plates. You know the voltage of each plate. V/m would be an appropriate unit to pick. Express volts as joules/coulomb and you get an electric field measurement in joules/(coulomb*meter). Another way to measure electric field is in terms of newtons per coulomb. You might pick this set of units because you are measuring an electric field by inserting a test charge into the field and measuring the force on the test charge. When you divide newtons expressed as (joules/meter) by coulombs, you get an electric field expressed in joules/(coulomb*meter). That's the same units as volts/meter! [To create this answer I used Khan Academy's experimental AI tutor, "Khanmigo" to get a starting point. Then I revised the response to (hopefully) make it more clear. This is my first experience using an AI.] (3 votes) cassiecsy96 8 years agoPosted 8 years ago. Direct link to cassiecsy96's post “how is electrostatics rel...” how is electrostatics related to transformers? • (1 vote) APDahlen 8 years agoPosted 8 years ago. Direct link to APDahlen's post “Hello Cassiecsy,Nearly ...” Hello Cassiecsy, Nearly every electronics and physics textbook begins with a discussion of electrostatics. There is talk about charge, charge carriers, and the transfer of charge. These concepts lead an understanding of voltage and current. Electrostatics helps us understand how we move these charge carriers (electrons in a wire). How to describe the concepts and how to perform measurements. Since in all cases we are talking about the movement of charges electrostatics has everything to do with transformers. On the other hand, transformers are electromagnetic devices. Only the vocabulary of electrostatics is used. Unlike capacitors which store energy in electrostatic fields... Sorry, it's not a simple answer. Please leave a comment below if you would like to continue the conversation. Regards, APD (4 votes) jw002332 4 years agoPosted 4 years ago. Direct link to jw002332's post “1. What is 1/4πϵ0? Is it ...” 1. What is 1/4πϵ0? Is it the same as k? • (1 vote) Willy McAllister 4 years agoPosted 4 years ago. Direct link to Willy McAllister's post “1. Yes. 1/4pie_o = k. It ...” 1. Yes. 1/4pie_o = k. It is just two forms of an arbitrary constant. The 1/4pi comes from a theory you study later in electromagnetics, Gauss's Theory, which deals with the surface area of a sphere (that's where 1/4pi comes from). Since Gauss's Theory is so important and is naturally written with the 1/4pi notation, some teachers bring that form all the way back to Coulomb's Law. 2. Yes. Coulomb's Law IS the electric force equation. 3. Coulomb's Law arises from a real-world experiment. It is not something you can derive from first principles. Coulomb himself designed and performed the experiment to measure electric force, and used the data he recorded to create the Law named for him. The little ri at the end is a vector notation to indicate the force lies along the line between the two charges. (4 votes) js15005 3 months agoPosted 3 months ago. Direct link to js15005's post “how fast is the speed of ...” how fast is the speed of light? • (1 vote) Coding Potter 3 months agoPosted 3 months ago. Direct link to Coding Potter's post “Simple answer, it is `3 x...” Simple answer, it is To give you a picture, light takes (2 votes) pickaboo👀 4 years agoPosted 4 years ago. Direct link to pickaboo👀's post “does a force exists and s...” does a force exists and shows its effect around an isolated charge present in free space • (1 vote) Willy McAllister 4 years agoPosted 4 years ago. Direct link to Willy McAllister's post “An isolated charge create...” An isolated charge creates an electric field in the free space surrounding the charge. There isn't a force in free space because there is no other particle in the vicinity. Force only exists if there is a physical body present to experience it. When you introduce a small test charge to the neighborhood of the first charge, the test charge will experience a force. You can say the force comes from Coulomb's Law "acting at a distance", or you can say the force is caused by the electric field that exists in the space surround the first charge. (2 votes)Want to join the conversation?
If you see a problem statement like "assume a uniformly charged rod," that's an example of the continuous peanut butter version of charge. Continuous charge will include a density specification like 2 coulombs per meter, or 3 coulombs per cubic inch.
2. Is Coulomb's Law the same as the electric force equation which is Fe=k(q1q2/r^2)?
3. Could anyone explain where [ F = (1/4πϵ0)(Q times Qi/r^2)(ri) ]?3 x 10^8 m/s or 1.07 billion km/h. 8 minutes to travel from sun to earth. On the other hand, the fastest bullet train on earth (maximum speed being 460 km/h) takes about 7.7 million years!
