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.
Hello,
I may be thinking out of my element here but I am considering a project. I want to build a recumbent trike that is electric powered. I want to take a slightly different approach however. I want to use the pedals to turn a generator to assist in the recharging of the batteries...
Homework Statement
A) Determine the net force on charge 1.
B) What is the net electric field acting on charge 1?
Homework Equations
Fnet
Enet
The Attempt at a Solution
Let North and East be positive.
Because of symmetry, F21 = F31
F2 = F3
F2 = (9.0x109)(2.0x10-5(3.0x10-5) / (2.0m)2
F2...
https://www.wired.com/story/even-more-evidence-that-electric-cars-could-save-the-planet/
There's a cool map showing mpg for electrics by state in the US based on how the electricity is being generated.
Homework Statement
An oil droplet is suspended between two horizontal parallel plates with a separation of 0.4 cm. If the potential difference of 320V is applied to the plates, determine the number of electrons transferred to/from the droplet.
Given/Known Values
mdroplet = 5.2×10-6 kg
d = 0.4...
I have a non conducting sphere with a charge ρ=A/r per uni vollume A is constant. suppose there is a cavity in the centre and within a particle of charge q. i want to find the E inside the sphere in respect with r.
Homework EquationsThe Attempt at a Solution
for radius equal of the cavity i get...
This is problem 4.13 from Griffiths (edition 3).
The question asks:
A very long cylinder, of radius a, carries a uniform polarization P perpendicular
to its axis. Find the electric field inside the cylinder. [Careful: I said "uniform," not "radial"!]
I decided to try and find the bound charges...
Find the electric field strength at point B between two charges shown below:
Given/Known Values
q1 = 4.0×10-6 C
r1 = 40 cm = 0.4 m (Distance from q1 to point B)
q2 = -1.0×10-6 C
r2 = 30 cm = 0.3 m (Distance from q2 to point B)
k = 9.0×109 Nm2/C2
Equations
Electric Force:
FE = (k⋅q1⋅q2)/r2...
I need to perform stress analysis for the stand for an industrial sized electric motor like pic related. The motor stands on four legs. I need to know the force that the legs of the motor exert on the stand due to its torque. I have all the dimensions of the motor including weight and torque...
Homework Statement
This is problem 4.13 from Griffiths. A long cylinder of radius a carries a uniform polarization P perpendicular to its axis. Find the electric field inside the cylinder.
Homework Equations
##\int \vec{E}\cdot dA = q_{encl}/\varepsilon_0##
The Attempt at a Solution
[/B]
We...
I tried redrawing the above circuit so that it resembles more like the circuit diagrams we see from day to day. However, what confused me was when it asks for the resistance measured between A and B versus between A and C What's the difference between those two, and how would the calculations...
If there is a very very big(infinitely big) region of space where ## \frac {dB} {dt} = constant ## what would be the E field at any point? Obviously ## \nabla x E = constant ## but what after that ?
Homework Statement
Calculate the net electric field at point A.
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Homework Equations
Enet(total)
The Attempt at a Solution
[/B]
The electric field at point A will due to charge 2 will point towards charge 2 because charge 2 is negative.
The electric field at point A will due to charge...
Homework Statement
As an electron (q2) moves from point A to point B, it moves farther from a positive charge (q1). Does the electric potential energy increase, decrease, or stay the same.
Homework Equations
U=-kq1q2/r
The Attempt at a Solution
The electric potential energy decreases in...
Homework Statement
Homework Equations
Gauss's Law
The Attempt at a Solution
I simply used logic and observed the symmetry of the cube. If the charge is placed on the middle of the cube, the flux would simply be Q/∈0. The face of the cube itself can be split into 4 squares, with the charge at...
https://phys.org/news/2018-03-world-first-air-breathing-electric-thruster.html
If it dipped into the atmosphere temporarily on an elliptical orbit, could the air gathered be stored for a long flight? Then maybe get more fuel from another planet's atmosphere or moon for the return trip?
There's something I need to confirm about Gauss' law. If I have to determine the electric field at point P due to charge +q, I take a Gaussian sphere enclosing the charge with the point on the surface of the sphere. So Gauss law doesn't care about the charge +Q because the flux do to this charge...
Homework Statement
In a TV tube, an electric potential difference accelerates electrons from a rest position towards a screen. Just before striking the screen, the electrons have a wavelength of 10×〖10〗^(-11) m. Find the electric potential difference.
Homework Equations
∆E_K=q∆V
λ=h/mv
The...
As I understand it, electrical potential is the potential energy of a unit charge in some point in space. How does this idea relate to the idea of voltage in a circuit? The term electric potential seems to be used for both.
The electric field inside of a conductor is 0, but what exactly does inside a conductor mean? It’s easy enough to understand what this means if the conductor is closed, but what if the conductor is open in some way? What counts as inside and what doesn’t?
Homework Statement
Examine the charge distribution shown.
b) What is the net electric field acting on charge 1?
Homework Equations
I used the equation E= (kq1/r^2) + (kq2/r^2)
The Attempt at a Solution
I subbed 9.0 x 10^9 in for k, 3.0 x 10^-5 for both q1 and q2, and 2m for r.
My final answer...
Hi,
Can anyone direct me to some literature that describes the numerical solution of full Maxwell's equations and Navier-Stokes equations for two-phase/multi-phase flows in coupled electric and magnetic fields.
Thanks!
Homework Statement
The textbook says to find the electric potential due to a point charge by moving a test charge from R to infinity, and integrating using the equation below. But when I integrate from infinity to R, the sign switches. Why is that? Both times, electric potential at V is 0...
Hi,
I am confused about the electric field lines which are depicted mostly on the Internet as per conventional way.
What I understand that the conventional current was due to positive charges which was wrong. Actual flow of the current was due to the negative charges or electrons. When the...
Homework Statement
You intend to suspend water droplets in mid-air to understand rainfall.
You give the droplets a small positive charge, and keep them suspended by an electric field upwards.
The experiment consists of two horizontal metal plates, separated by 9.3m. The water droplets have a...
*This is a question in an assignment that i have to submit.
1. Homework Statement
Two imaginary spherical surfaces of radius (R) and (2R) respectively surround a positive point charge (Q) located at the center of the concentric spheres. What is the number of electric field lines (N2) going...
Homework Statement
Two point charges are placed on the x axis.(Figure 1)The first charge, q1 = 8.00 nC , is placed a distance 16.0 m from the origin along the positive x axis; the second charge, q2 = 6.00 nC , is placed a distance 9.00 m from the origin along the negative x axis.
Find the...
Does static charge near to a constant current carrying conductor experience force on it?
I am asking this question because i have learned that electric field and mangnetic field are same thing but viewing differently with respect to the frame of reference...when a positive test charge moves (...
Homework Statement
The electric field inside a parallel plate capacitor is measured to be E= -3500 N/C i. The electric potential at point XA = 3.00 m is measured to be 1500V. What is the electric potential at point XB = 0 m?
Homework Equations
V=E⋅s
The Attempt at a Solution
I think I need to...
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I'm very lost here, I don't know where to begin. My instructor is little help, the notes he gives are not even useful, and I cannot find anything in the book.We were...
So here is how my book defined electric potential. If you take a charge, it will have a corresponding electric field associated with it. If you put another charge in that electric field, an electrostatic force will act on it and give it kinetic energy. This kinetic energy can't come from thin...
Supposedly the strength of the electric field is is related to the distance between electric field lines. I have two questions about what exactly this means.
1.) What is the distance between electric field lines? Is it just the distance between two points on adjacent electric field lines that...
If the force acting between two point charges were proportional to \frac{1}{r^ 3}, instead of \frac{1}{r^ 2}, what would be the electric field intensity and charge density inside a charged solid metallic sphere?
Homework Statement
Find the field at A.
Homework Equations
##\oint E\cdot dA = Q_{enclosed}/\epsilon_0##
The Attempt at a Solution
My first intuition was to do a Gaussian cylinder from A to the middle of the bottom plate. My logic is that the field inside the bottom plate is 0, so I'd have...
If the electric field is uniform, the electric flux passing through a surface of vector area S is
,
where E is the electric field (having units of V/m), E is its magnitude, S is the area of the surface, and θ is the angle between the electric field lines and the normal (perpendicular) to S...
Hello,
what is the consensus on using super capacitors to power a 500w electric bike motor.
cheap and innovative alternative to li-po batteries or explosion between thighs waiting to happen?
the plan is to create something like this:
i will use a 24V motor...
Hello,
I'm currently constructing an electric bicycle using a 500w 24v motor, 2X24v 7ah batteries (maybe 4 later on). I bought a 24v 30a dimmer switch to use as a "throttle". During the intitial test (on a table, not on the bike!) It worked absolutely fine for 2 minutes, but then began to smoke...
Homework Statement
Consider the hollow cylinder from Exercise 1.59. Use Gauss’s law to show that the field inside the pipe is zero. Also show that the field outside is the same as if the charge were all on the axis. Is either statement true for a pipe of square cross section on which the...
I believe the electric flux within a closed space can be found with the equation phi = Q/ε0. Can this be used for volume and area, or just volume?
Also what good does this do. Why would I want to know the electric flux of something?
Question:
A) A small charged sphere is attached to a thread and placed in an electric field. The other end of the thread is anchored so that the sphere is in a static situation when placed in the field. If the thread is horizontal, find the magnitude and direction of the electric field. The...
Homework Statement
An Ohmic material with some conductivity has a uniform current density J initially. Let's say the current is flowing in the direction of the z-axis. A small insulating sphere with radius R is brought inside the material. Find the potential outside the sphere.
Homework...
Suppose I were to subject a polar molecule to a high-frequency electric field. The polar molecule responds to the high-frequency electric field and thus it has a time-varying electric dipole moment vector. If we treated this as a classical electric dipole, it would be expected to radiate some of...
Homework Statement
(a) Two long, thin parallel rods, a distance 2b apart, are joined by a semicircular piece of radius b, as shown in Fig. 1.44. Charge of uniform linear density λ is deposited along the whole filament. Show that the field E of this charge distribution vanishes at the point C...
a DC electric train or tram uses a single overhead wire unlike it's AC counterparts like trolleys which use two, so if there is only a single overhead wire I assume that the return wire or let's call it ground for the electric DC train are the rails correct?
Does this mean that it is important...
Homework Statement
Three 18-cm long rods form an equilateral triangle. Two of the rods are charged to +10 nC, and the third to - 10 nC.
What is the electric field strength at the center of the triangle?
Homework Equations
$$ \vec{E} = \frac{k*q}{r^2} $$
The Attempt at a Solution
1. Draw...
The electric field experienced by the points on the surface of the shell is put out as
KQ/R^2
where Q is charge on shell and R is radius of shell...
But the gaussian surface corresponding to the case intersects the sphere, which means there are non-infinitesimal charge quantity sitting on the...
when a em waves strikes a dielectric the atoms vibrate in response to the electric field and if the frequency matches the resonant frequency the Lorentz oscillator the electric field is absorbed how a field can be absorbed we know the em field contain energy how is the em field destroyed is some...