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.
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...
Homework Statement
A charged sheet with charge density ##\sigma## is described by ##-\infty<x<0,-\infty<y<\infty, z = 0##. Find the electric field at ##(0,0,z)##.
Homework Equations
Electric field of continuous density charged body from the Coulomb law:
$$E = \frac{1}{4\pi...
In the textbook (Introduction to Electrodynamics by Griffiths), the problem in the attached image asks to find the electric field ##E## outside a dielectric. The problem consists of dividing the electric field into the one produced by the negative charges in the dielectric and another by the...
So in my textbook (Introduction to Electrodynamics by Griffiths) it said that inside a conductor, the electric field E would have to zero, since if it wasn't the free charges would move accordingly and create a electric field that cancels the original field. But in a question that soon followed...
A cable of resistance 12 Ohm carries electric power from a generator producing 250 kilowatt at 10,000 volts. Calculate the current in the cable.
Solution
using P=VI
I=25A
but using P=I^2R
250000=I^2×12
I =500/root 12 Amps
What is the reason for the different...
Homework Statement
What causes electric field? What causes magnetic field?
(I) stationary electric fields
(II) moving electric charges
(III) a changing magnetic field
IV) a current-carrying wire
Homework Equations
E=F/q
B=μI/2πr
E electric field
F elecric force
Q charge
B magnetic field
I...
Homework Statement
Given two very long lines each is charged with linear density +lambda Coulombs/meter. The two lines are separated by a distance of d metres.
A) show the electric field E, at any point along one of the lines due to the other line is
E = lambda/(2 (pi)(epsolon o)(d))
(Note...
Hello, I want to create a handheld electric field meter to measure the strength at a certain point with an arduino. I have seen various ideas online but I am still not sure what kind of design to use.
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Homework Statement
In the file
Homework Equations
No equations needed
The Attempt at a Solution
I answered it C. Since I learned that at the tip there are most of the charges. Therefore, it’s the point of the greatest E field magnitude. But another tutor told me that it is a circle, and...
Homework Statement
This problem is belonging to a book, which is material for Vietnamese students who will take part in IPhO (International Physics Olympiad). Since this problem is written in Vietnamese, I will try my best to translate it to English:
A vacuum diode consists of two parallel...
Homework Statement
An electron and a proton are each placed at rest in an electric field of 687 N/C. What is the velocity of the electron 56.5 ns after being released? Consider the direction parallel to the field to be positive. The fundamental charge is 1.602×10−19 C, the mass of a proton is...
Homework Statement
Homework EquationsThe Attempt at a Solution
I am having trouble figuring out why the answer is A) the electric field points radially between A and B. I think it is because since the point between A and B is mostly negative, the electric field would point outwords more...
The setup for one magnet
Introduce a magnet:
Inertial Frame 1 (or lab frame)
A frame where a magnet is seen to move with uniform velocity v and carries a uniform polarization P while a point charge Q is seen to be stationary at time t=0.
Inertial Frame 2 (or material frame)
A frame where a...
Homework Statement
Homework Equations
E=KQ/R^2
The Attempt at a Solution
I'm kinda confused at what the question is asked. It is in terms of x, but I thought the integral for potential is V=int(Edr)? Also, should it be integration starting from infinity? Why is the integration from -2 to 3...
Homework Statement
determine the electric flow through a square surface of side 2l due to a load + Q located at a perpendicular distance l from the center of the plane
I really don't know how to answer this question .i need help guys
Thanks
Homework EquationsThe Attempt at a Solution
I ended...
Homework Statement
Homework Equations
V=kQ/R
The Attempt at a Solution
The answer is B)kQ/R. It is because V= k(2Q)/R. I don't understand why Q=2Q in this case. Isn't the point on the inside of the outer shell, so the Q for the equation is just Q?
Homework Statement
Consider a spherical shell with uniform charge density ρ.
The shell is drawn as a donut with inner (R1) and outer (R2) radii.
Let r measure the distance from the center of the spherical shell, what is the electric field at r>R2, R1<r<R2, and r<R1.
I am working on the r > R2...
Homework Statement
A) Use Gauss's Law to derive the electric field in all space for a non-conducting sphere with volumetric charge distribution ρ=ρ0r3 and radius, R.
B) Repeat when there is a concentric spherical cavity within the non conducting sphere with radius, A.
Homework Equations...
Homework Statement
a)recall that electric potential is a scalar quantity. For a circular ring of radius, R', carrying charge, Q, what is the electric potential at a height,y, above the center of the ring?
b)Use your above answer to determine the electric potential at a height,y, above the...
Homework Statement
Hello, I am wondering if I am thinking about electric potential correctly:
Stop me if I am wrong:
V=electric potential, the electric potential is created by source charges altering space around them.
If you place a test charge, q, within that space we can say it experiences...
Okay here's an example of what not to do when working with 230v... So I was about to repair some outdoor lights so I went to the circuit breaker panel and switched off all the power in that area for safety. I began to remove the light and disconnected the wires, then I was about to install the...
Hi,
I learned about how PE = U=kq1q2/r is the electrical potential energy for the system. It is found by taking the integral of electrical force and dr from infinity to the point of location we are interested in.
So that is the intregral(F*dr) from r=inf to r=ro.
My question is that do I...
Homework Statement
This is the question
Structure opposite comprises 5 ions each of which has lost one electron. The sides of the square formed by the 4 outer ions are of length 0.2nm
Ion E is at the midpoint
1.What is the force on A due to ion A?Homework Equations
I'd imagine: F= kq / r^2...
Homework Statement
My textbook is no help, my teacher is no help, so I've found myself here. I am having a difficult time understanding the differences in
1.Electric Potential energy
2. Potential Difference
3. Electric potential
Im sure this question has been asked tons of times but I need...
Homework Statement
A spherically symmetric charge distribution produces the electric field E=(200/r)r(hat)N/C, where r is in meters.
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Homework Statement
A spherical cavity is hollowed out of the interior of a neutral conducting sphere. At the center of the cavity is a point charge, of positive charge q. (picture attached)
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Homework Statement
Two small insulating spheres with radius 9.00×10−2m are separated by a large center-to-center distance of 0.545 m . One sphere is negatively charged, with net charge -2.35 μC , and the other sphere is positively charged, with net charge 4.35 μC . The charge is uniformly...
Homework Statement
I'm not sure if the construction of this circuit is correct, so that both lamps, which are the same, shine equally brightly. Otherwise only the resistors are given. If it's wrong, what else would it look like? And why?[/B]
Homework Equations
I guess the laws of Kirchoff...
Homework Statement
The figure below shows a thin, vertical rod of length L with total charge Q. The indicated point P is a horizontal distance x from the one end of the rod. What is the electric field at point P. Express your answer in component notation in the two blanks below.
L = 5.0 cm, Q...
Homework Statement
The figure below shows a thin, vertical rod of length L with total charge Q. The indicated point P is a horizontal distance x from the one end of the rod. What is the electric field at point P. Express your answer in component notation in the two blanks below.
L = 5.0 cm, Q...
Homework Statement
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Homework Equations
kq/r^2
The...
Homework Statement
A 2cm x 3cm rectangle lies in the xy plane. What is the electric flux through the rectangle if
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Homework Equations
Φe=E⋅Acosθ (Electric Flux Equation)
The Attempt at a Solution
My question is to find the magnitude of the electric field we...
I want to do an application that can connect to my Electric scooter (the kind you stand on)
and can get a speed and engine temperature readings,
i'm looking into a device
i can attach to the wheel
or a temperature gauge
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and get a reading from both of them
something i...
if we had an entire car made of Starlite (a material that was created resistant to 18032 °F). Would the efficiency of the combustion engine be close to that of the electric and that of the electric would be almost 100% efficient?
https://en.wikipedia.org/wiki/Starlite
Homework Statement
Before diving into the quantum-mechanical superposition principle, let’s get some practice with superposition in classical physics. Consider an electromagnetic wave propagating in the z-direction, which is a superposition of two linearly polarized waves. The electric field...
When to use ## V =-\int E ⋅ dl ## or ## V =\int E ⋅ dl ## ?
When i use ## V =-\int E ⋅ dl ##. i can not show that P = IV because ##\frac{ln \frac{b}{a}}{ln \frac{a}{b}} ≠ 1##
But the solution use ## V =\int E ⋅ dl ## I'm concerned about using "minus" .
Homework Statement
You are given a non conducting rod carrying uniformly distributed charge, -Q, that has been bent into a 120° circular arc of radius, R. The axis of symmetry of the arc lies along the x-axis and the origin is at the center of curvature of the arc.
(a) in terms of Q and R...
Homework Statement
Derive the electric field a distance, z, above the center of a single uniformly charged ring of radius, R, with a linear charge density, λ. You are now given two uniformly charged concentric rings. The inner ring has radius, R, and carries a uniformly distributed total charge...
Homework Statement
At what distance, a, along the axis of a uniformly charged disk of radius R is the axial electric field strength equal to one half its value at the surface of the disk at the center.
Homework Equations
electric field of disk (attached)
The Attempt at a Solution
First I...
Why is the electric potential of an electron in a capacitor measured from the negative plate and not the positive plate here?
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Homework Statement
Homework Equations
charge density equations, electric field equations,
The Attempt at a Solution
My attempts are attached. The attachment labeled A, is part A. Part B took a lot of paper so there are two attachments labeled B1 and B2. It is really B and C that I am...
I'm looking for advice on how much power is required to compress air in a gas turbine engine - parameterised by degree of compression and mass flow.
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Ok so she says that electric dipoles are of opposite charge but equal magnitude at 3:40. But then at 5:33 she shows 2Q with -Q, at that point the magnitude of the 2Q particle wouldn't be equal to the -Q so they wouldn't be electrical dipoles right?
Hi, now I'm working on a project which involves a dc motor and high voltage. I'm developing a machine consists of a motor to rotate a platform disc and high voltage will be applied during the rotation. The problem is when I supply a positive high voltage at motor shaft during rotation, the motor...
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Homework Statement
A proton enters the uniform electric field produced by the two charged plates shown below. The magnitude of the electric field is 4.0 × 105 N/C, and the speed of the proton when it enters is 1.5 × 107 m/s. What distance d has the proton been deflected downward when it leaves...
Homework Statement
In the figure, an electron of mass m, charge − e, and low (negligible) speed enters the region between two plates of potential difference V and plate separation d, initially headed directly toward the top plate. A uniform magnetic field of magnitude B is normal to the plane...