Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others.
The presence of an electric charge, which can be either positive or negative, produces an electric field. The movement of electric charges is an electric current and produces a magnetic field.
When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by Coulomb's law. If the charge moves, the electric field would be doing work on the electric charge. Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of positive charge from an arbitrarily chosen reference point to that point without any acceleration and is typically measured in volts.
Electricity is at the heart of many modern technologies, being used for:
Electric power where electric current is used to energise equipment;
Electronics which deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies.Electrical phenomena have been studied since antiquity, though progress in theoretical understanding remained slow until the seventeenth and eighteenth centuries. The theory of electromagnetism was developed in the 19th century, and by the end of that century electricity was being put to industrial and residential use by electrical engineers. The rapid expansion in electrical technology at this time transformed industry and society, becoming a driving force for the Second Industrial Revolution. Electricity's extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is now the backbone of modern industrial society.
Homework Statement
A proton located several proton diameters away from a small charged object carrying charge q is subject to an electric field of magnitude E. As the proton moves a distance d along the x-axis away from the object, the electric field magnitude drops to E/4.
If the charged...
Homework Statement
Find electric field at Point A
its an arc with uniform density= lamda
https://drive.google.com/file/d/14cBqE2dMe_w0nb9LtPG0h1cUOrzGWt6g/view?usp=sharing
the problem
Homework Equations
E=intergal dq/r^2
The Attempt at a Solution
I've tried using wolfram and cosine rule to...
Homework Statement
A distribution of charge with spherical symmetry has volumetric density given by: $$ \rho(r) = \rho_0 e^{ \frac {-r} {a} }, \left( 0 \leq r < \infty \right); $$
where ##\rho_0## and ##a## is constant.
a) Find the total charge
b) Find ##\vec E## in an arbitrary point...
Homework Statement
https://www.physicsforums.com/threads/find-the-electric-field-in-the-point-p-of-a-right-triangle.965285/#post-6125768 knowing that the three charges are equal and that the angles of the triangle are 90°, 45°, 45°.
Homework Equations
The Attempt at a Solution
I tried...
I'm in the snow removal business and am unhappy with my snow plow on residential driveways. I am going to fabricate a light duty power brush for my vehicle, and I am going to power it with an electric motor and battery pack for quiet operation and relative simplicity.
The demands on this power...
Homework Statement
A rod of charged -Q is curved from the x-axis to angle ##\alpha##. The rod is a distance R from the origin (I will have a picture uploaded). What is the electric field of the charge in terms of it's x and y components at the origin? k is ##\frac {1} {4\pi \epsilon_0}##...
Every time I take a train I sort of think about this, so the electrified overhead wire (DC or AC) and the rails form a transmission line and the train is a load that moves along the transmission line.
Let's talk about the DC case as it seems more simple, so when the train is at or near a...
Homework Statement
In the figure above, charge A is -5.00 nC, charge B is 10.0 nC, and charge C is 5.00 nC. If x = 2.10 cm and y = 4.20 cm, what is the electric field at the dot?
Homework Equations
E = kq/r^2
The Attempt at a Solution
r = distance from A to point = sqrt(x^2+y^2)
Ea = kq/r^2...
I am doing some research into atmospheric energy harvesting. To design a proper feasibility experiment, I need to establish some theoretical baselines. I see a lot of values for the field strength for example, tossed about from various papers. However, there does not seem to be a standard...
Homework Statement
Find the electric field of a point outside sphere without using Gauss's law. (Do not evaluate the integral)
Homework Equations
Coulomb's Law
Spherical Co-ordinate System
The Attempt at a Solution
I have attached my attempt as a picture but now I am stuck, I don't know how I...
Homework Statement
Why is it inefficient to use low voltage when transmitting electricity?
Homework Equations
P∝i2
P=Vi
H=Vit
P=Ri2
E/ti2=V/i
These are all basically the same few formulas, but I wrote down all iterations of them.
Anything from Joule's Law/Joule Heating
The Attempt at a...
Consider an electric dipole consisting of charges ##q## and ##-q##, both of mass ##m##, separated by a distance ##d##.
If the dipole is given an acceleration ##a## perpendicular to its moment the total electric force on it, due to each charge acting on the other, is given approximately by...
Homework Statement
A point charge of 6 × 10−9 C is located at the origin.
The magnitude magnitude at ##\langle 0.6,0,0\rangle## m is 150 N/C
Next, a short, straight, thin copper wire 5 mm long is placed along the x axis with its center at location ##\langle 0.3,0,0 \rangle## m. What is the...
Hi!
Could you please help me with the queries below? Thanks a lot.
Question 1:
My question is about the field outside the plates of parallel plate capacitor. It is said that the field(s) between positively and negatively charged plates gets added up but the field(s) outside the plates gets...
Homework Statement
A dipole is located at the origin, and is composed of charged particles with charge +e and -e, separated by a distance 2x10-10m along the x-axis.
Calculate the magnitude of the electric field due to the dipole at location ##\langle 0.2\times 10^{-8}, 0, 0\rangle##m
Homework...
Consider a multi-electron atom. (In our course we deal with alkalis mostly so that we have energy levels which are similar to the hydrogenic ones with quantum defect. I don't know if that is relevant here)
Edit: l = orbital angular momentum of a single electron, L = total orbital angular...
Homework Statement
We have an incident electric field, and there are two cases:
1) the field is polasised perpendicularly to the incidence plane (TE)
2) polarised in the plane (TM)
Here I must be able to correctly apply the limit conditions, to find the Fresnel formulas that give the...
Hello there,
I'd like to model a simplified version of a "Magic Eye" tube (e.g. without the amplification triode, and for a start, 2 dimensions only), or the visible display behavior.
What I'm talking about:
https://en.wikipedia.org/wiki/Magic_eye_tube#Operation
Here is a nicer depiction of...
Hello guys!
The electric field created by a conductor at a point $M$ extremely close to it is ##\vec{E}=\vec{E_1}+\vec{E_2}## where ##\vec{E_1}## is the electric field created by such a tiny bit of the conductor that we can suppose it to be a plane, and since ##M## is extremely close to the...
Hi,
I've been interested in the science behind electrons/magnetism for quite a while. I've been learning quite a bit from various sources online. However there is one thing that's really nagging me.
Magnetic fields result from moving electrons. That indicates that a permanent magnet has...
Homework Statement :
[/B]
If the length of the filament of a heater is reduced by 10%, the power of the heater:
Options are-
a) increases by about 9%.
b) increases by about 11%.
c) increases by about 19%.
d) decreases by about 10%.
Homework Equations :
P[/B]=I2R
Or
P=V2/R
Where P=power...
1.Data: We have an truncated cone with a volumentric charge density ρ, and it's uniform. The image show the truncated cone and show some info of the radios.
2. Question. We need to calculate the potential on the vertical axis.
note: adding an image of the problem but it's in spanish, hope...
Homework Statement
Two charges, one of 3.2 x 10 ^ -9 C, the other one of -6.4x10^-9 C are 42 cm apart. Calculate the net electric field at point P, 15 cm from the postie charge, on the line connecting the charges
(+) -------------(Point)---------------------- (-)
15cm...
Homework Statement
An electron enters the lower left side of a parallel plate capacitor and exits precisely at the upper right side (just clearing the upper plate). The initial velocity of the electron is 7*10^6m/s parallel to the plates. The capacitor is 2cm long and its plates are separated...
Homework Statement
A solid non-conducting sphere of radius R carries a uniform charge density. At a radial distance r1= R/4 the electric field has a magnitude Eo. What is the magnitude of the electric field at a radial distance r2=2R?
Homework Equations
Gauss's Law: ∫EdA=Qencl / ε0
Charge...
Hello,
I am trying to measure the time-varying electric field of a parallel plate capacitor using short dipole antenna, but my numbers are off by almost 100 times. I have a parallel plate capacitor, A=23cmx11cm, d=10cm. I apply 10sin(2pi*1KHz) and 10sin((2pi*1KHz)+180deg) to each plate. I am...
I was wondering how spacecraft s discharge when encountering van allen belts (for example the juno spacecraft around jupiter) since obviously there is no earthing and is it possible to remove excess charge to power something on the craft?
Homework Statement
My main conceptual issue here surrounds positives and negatives as they apply to electric potential difference. I will post two questions that illustrate my confusion, if that's ok.
1) The electrons in an old TV picture tube are accelerated through a potential difference of...
Homework Statement
See picture.
Homework EquationsThe Attempt at a Solution
I tried at first just doing (1/3)*(48kJ) to get the energy dissipated, but that would i=give me 16kJ
I am currently in grade 12, and for a physics project (a huge project, which gets assigned to you at the start of the semester and needs to be completed just before exams. You think up your project, make a proposal for it and you prove your hypothesis to be right after a presentation and lab...
I was studying Feynman Lectures on Physics Volume 1 chapter 29. In there he proves that electric field propagates like a wave. Here is my attempt (in image), please tell me my mistake.
Thank you
Homework Statement
I'm trying to do a problem two ways, and things aren't consistent, finding the electric potential difference in a linearly varying field.
The electric potential difference between two points is often summarized in texts as ΔV = Vf - Vi = - ∫ E⋅ds where the lower bound of...
1. The problem statement
Two charges of 3μC and -2μC are placed 2cm apart. At what point along their connecting line is electric potential zero?
Homework Equations
Electric potential superposition Φ=Φ1-Φ2 since q2 is negative
Φ=kq/r^2
The Attempt at a Solution
Let’s say the charges are on the...
1. We've been given a spherical capacitor with radius of 1 cm for inside electrode and 2 cm for outside electrode. Voltage between electrodes is 360 V and the task is to find largest and smalles electric field strength in capacitor.2. I'm not sure how voltage given in capacitor works and how to...
There is no absolute electric potential.
Is it due to classical ignorance (because we don't know the static fields, capacitive coupling, etc. of the surrounding environment) or is it due to quantum ignorance (the potential can fluctuate to any value due to HUP)? My question is valid because...
Homework Statement
The question is exactly the same as this question
https://physics.stackexchange.com/questions/250297/metal-sphere-in-a-uniform-electric-field
However, it says "Then by symmetry the entire xy plane is at potential zero" in the book. I don't understand this.
Homework...
Homework Statement
Hi guys, my exam is in four days and my tutor for the electromagnetic module is neither very active nor very competent, so I would like you guys to check my solution for this question. I am afraid I might have messed up some signs or some linear algebra.
Homework Equations...
Dear all.
I would like to know the general expression of the ratio of the electric field strength E to the magnetic flux density B. I know E/B = c, where c is the speed of light, for a vacuum, but I want to know if this is stil valid for any material where the electric and magnetic fields are...
Hello all,
The second quantization of a general electromagnetic field assumes the energy density integration to be performed inside a box in 3D space. Someone mentioned to me recently that the physical significance of the actual volume used is that it should be chosen based on the detector used...
Homework Statement
We have the cross section of a metal pipe that has been split into four sections. Three of the sections have a constant electric potential, Vo. The fourth section is grounded so electric potential is zero. We are looking for electric potential inside and outside of the pipe...
Homework Statement
Introduction to Electrodynamics (4th Edition) By J Griffth Ch.4
Problem 4.18
The space between the plates of a parallel-plate capacitor is filled with two slabs of linear dielectric material. Each slab has thickness a, so the total distance between the plates is 2a. Slab 1...
Suppose a straight current carrying wire is immersed in a uniform electric field along its axis. For this problem, please don't worry about complete loops or return paths, just consider a segment of straight wire carrying a current. Since external electric fields don't get inside conductors due...
Homework Statement
There is a 3nC charge at (-3,0), -6nC at (0,2) and 5nC at (1,0). What is the electric field at the origin (0,0)?
Homework Equations
##E = \frac{Q}{4 \pi \epsilon_0 r^2}##
The Attempt at a Solution
i think its ##(\frac{1}{4 \pi \epsilon_0})(-\frac{14}{3} i - \frac{3}{2} j)##...
If the circuit has 200 V supply.
The resistance R that must be put in series with bulb so that it draws 500 w is?
2. Relevent equations
P= v^2/r
I = v/r
3. My attempt at the solution
R= V^2/P r (bulb)= 10000/500 = 20 ohm
Now for 200 v supply ..
P= 500 W
V= 200V
Rnet = 20 + R
R+20= 80
R= 60...
Hello everyone !
I'm Hugo. I'm a french high school student. This year I've a project on new way to store electricity and their materials.I've done researches on super capacitors. But I've found only that "new way" to store electric energy. And for the material part, I don't know what I can...
The electric potential can be defined as
V = - ∫C E⋅dl
where we are taking the line integral along C from some convenient reference point O, where we have set V = 0, to the point r we are trying to find the potential at. Of course, C can be any curve, but it's usually the most convenient to...
Dipole problem (which is solved through mirror imaging) has been troubling me with its solution. I understand everything except how the dipole moment's coordinates came to be, since when converted into x-y axis, its doesn't make sense. (problem 4.6)
The screenshot contains the solution which...