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.
Hi! I need help with this problem. I tried to do it the way you can see in the picture. I then has this:
##dE_z=dE\cdot \cos\theta## thus ##dE_z=\frac{\sigma dA}{4\pi\epsilon_0}\cos\theta=\frac{\sigma 2\pi L^2\sin\theta d\theta}{4\pi\epsilon_0 L^2}\cos\theta##.
Then I integrated and ended up...
Hi! I need help with this problem. I tried to solve it like this:
First I calculated the electric field of each ring:
Thus the electric field at a point that is at a distance z from the ring is ##E=\frac{Qz}{4\pi\epsilon_0(z^2+r^2)^{3/2}}##, Thuss for the upper ring, the electric field would be...
Hi! My main problem is that I don't understand what the problem is telling me. What does it mean that the surface is a flast disc bounded by the circle? Is the Gauss surface the disc? Does that mean that inside the circle in the figure, there is a disc?
Can you give me some guidance on how to...
I was looking at a sphere that has a positive point charge at the center of a sphere with radius R. Now, I understand that the electric field is pointing outwards (in the direction of dA), so
$$d\phi = EdA$$
However, I am told that since the magnitude electrical field is the same because the...
I have no idea how to approach the problem using Gauss's Law.
I found the electric field using superposition, and it was incorrect.
I am assuming you treat the wire as a continuous electric field, and then also treat the pipe as a continuous electric field. I solved for this using...
So I figured to get e-field at point (4,4,0), I need to find the resultant e-field from the negatively charged particle and the plate
##E_{resultant}=E_{particle}+E_{plate}##
##E_{particle}=\frac{kq}{d^2}=\frac{(9*10^9)(-2*10^-6)}{4^2}=-1125N/C##
Now for the plate is where I'm confused.
If this...
Homework Statement: The amplitude of the oscillating electric field at your cell phone is 4.0 μV/m when you are 10 km east of the broadcast antenna. What is the electric field amplitude when you are 20 km east of the antenna
Homework Equations: electric field
i've done
E=##\frac A...
i've started from this I1=I2
then
I1= JA1=##\frac {E l} R##
I2= JA2=##\frac {E_2 l} R##
but can't get anything useful relating them. Am i forgetting any other useful formula?
I get as result E4
Here is picture. Answers is A.
My attempt was that I thought if i were to place a positive test charge then it would go from top to bottom if there was a positive charge in the center it was avoiding and a positively charged particle at the top, but an electron at the bottom so it would avoid...
A fully electric mining truck has been built that does not burn fuel. It has a 600 kilowatt-hour battery pack, and they need to discharge about 200 KwH of that every night to keep from overcharging it. The secret: It's loaded at the top of the hill, and unloaded at the bottom. The regenerated...
The problem can be simplified to a configuration in ##x-y## plane where two point at ##y## axis with ##y=\pm R## have potential of ##0##, and two point at ##x## axis with ##x=\pm R## have potential of ##U=V_0 \cos \Omega_T t##.
The expression of ##U## is not important, the problem is now to...
Usually for a charge Q we state that for each point in space there exists a potential, and we can calculate this, draw graphs of potential etc.
However, if electric potential energy is a property of a system of two charges, and potential is PE for a 1C test charge, then how can we even define a...
Homework Statement: uniformly charged disk, radius r, with surface charge density ##\sigma##
. I want to find the electric field along the axis through the centre of the disk at a h distance
Homework Equations: ##dE=\frac {kdq}{r^2}##
My Solution:
##dE=\frac {kdq}{r^2}##
in this case r=s...
Homework Statement: A thin rod of length L and charge Q is uniformly charged, so it has a linear charge
density ##\lambda =q/l## Find the electric field at point where is an arbitrarily positioned
point.
Homework Equations: ##dE=\frac{Kdq}{r^2}##
A thin rod of length L and charge Q is...
So I figured out the potential is: dV = (1/(4*Pi*Epsilon_0))*[λ dl/sqrt(z^2+a^2)]
.
From that expression: We can figure out that since its half a ring we have to integrate from 0 to pi*a, so we would get:
V = (1/(4*Pi*Epsilon_0))*[λ {pi*a]/sqrt(z^2+a^2)]
In that expression: a = sqrt(x^2+y^2)...
I tried to work out both a) and b), but I am not sure if I am correct. I drew a picture with a sphere around q first with radius r and then with radius 3r.
For a) ##E.A=\frac {q}{ε_°}## (when using Gauss' Law)
Since ##A=4πr^2##, I substituted this in the equation and solved for E giving me...
Summary: Why is the electric dipole moment of the nucleus of an atom equal zero?
Summary: Why is the electric dipole moment of the nucleus of an atom equal zero?
I read about the hyperfine interactions that cause the altering of the energy levels of the nuclues of an atom. Under the...
Which is better to use? The equation for the area or the circumference of a circle?
Schaum's Electromagnetics (4 ed) by Edminister
vs
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elecyl.html
I am having trouble solving the following problem. I am given two positive charges on the x axis:
I know that the electric field strength at point P is ##E=150 \frac{V}{m}##, ##d=1.8m## and ##a=2.5m##. I want to find the charge of ##Q##. As far as I know, the electric field on the y-axis...
The contribution coming from a little segment of the ring is ##d\vec{E}=\frac{dQ}{r^2}cos\theta \hat{z}##, assuming that the horizontal components cancel out. But how can we show that?
I believe the answer is incorrect, reasons:
The answer assumes that electric field will exist .
But this is not the case , until and unless there is a bipolarity there cannot be an electric field ( in case of isolated charged objects, the field exists because the bipolarity is separated by a...
When a charge is at rest, it has an electric field only. When the charge starts moving , it is said to have accompanied a magnetic field. My question relates to its electric field while in motion. Does it still exist or not? I know in electron guns electrons are deflected while passing thru the...
Summary: I need to build an asymmetric capacitor, but the mathematics of electromagnetics become too tough, do you have any info that can help? Appreciate it!
Hello,
I am an undergraduate student in engineering and I want to build an asymmetric capacitor, so I need electromagnetics which I...
We are given: q1 = +2.0 x 10-5 C, q2 = q3 = -3.0 x 10-5 C, r31 = r21 = 2 m
a) We start by finding the electric force between q3 to q1 and q2 to q1
FE31 = k * q1 * q3 / r312
FE31 = (9.0 x 109 Nm2/C2) * (+2.0 x 10-5 C) * (3.0 x 10-5 C) / (2 m)2
FE31 = 1.35 N
FE21 = k * q1 * q2 / r212
Since...
I know how to find the electric field of more traditional designs i.e. a sphere, through Gauss' Law but I don't think Gauss' Law applies to this scenario. I tried to separate each part of the electrode into simple spheres and rods and using Gauss' Law to find these individual elements. This...
I'm curious if someone help me understand why the electric and magnetic forces are IN PHASE at right angles to one another?
Should they not be 90 degrees out of phase in order to conserve energy? I do understand they are in phase but why?
Thank you all for your time.
Merlyn.
Good morning
I'm no expert in classical physics, so I have one doubt. If I have a body with mass M, and I charge it electrically with x C (Coulombs), will its mass remain the same, or will it change (in which amount)? Can you help me in the case of a ball, let's say, with 1.5 Kg charged with...
I have been thinking about this subject for some time now, based on the following considerations
1) Many companies are working on Electric Aircraft Propulsion, high energy density Li-Ion batteries are used to power Electric motors and they drive propellers. This is the approach every one is...
If you place a zinc / copper battery it will create an electric field pointing from the copper to the zinc and my question is this what makes this electric field , the zinc pushes electrons in the circuit and never "stays" negatively charged for an electric field to be created same for the...
Hi, so I was able to solve this problem by just equating the forces (Tension, mg, and EQ).
But I thought I could also solve this problem with Conservation of Energy.
However, I calculated it several times, and I never get the right answer this way.
Doesn't the Electric Field do the work to put...
Options are at the top of page as a) b) c) d)
Answer may more than one.
Now since 'a' is distance from the smaller surface of cone so as we move along the axis area will increase,So current charge density will decrease and as we know J=sigma E,E will decrease,but V will remain constant since...
So I understand that when an electric field is produced in a conductor of length L, the net electric field in the conductor will be 0 because the rearrangement of electrons in the conductor results in the production of its own electric field which cancels out the one produced initially...
Ex =10.0Vm-1
dx= d2=x2+y2
x=4.00m
y=3.00m
d2=4.002+3.002
d=5.00m
Ex = -dV/dx
10.0Vm-1=-dV/5.00m
10.0Vm-1*5.00m=-dV
-50.0V=dV
So from origin at 100V-50.0V = 50.0V
But the solution I am given gives the answer at 50.5V and the information "directed at 45.0◦ " does not seem to have been used so may...
I bring a dielectric in a region with electric field ##\vec E_0##. Net electric field ## \vec E_{net} = \vec E_0 + \vec E_p ## , where ## \vec E_p ## is electric field due to polarization of dielectric.
For linear dielectric, ## \vec E_p ## is 0 outside the dielectric. So,
## \vec E_{net} =...
Why are there only two types of electric charge? I'm asking as a total layman in science.
I've started to wonder about this the more I watch popular science videos about the Standard Model of particles physics and about matter and antimatter. In particular, the various types of subatomic...
Problem Statement: i have a steering wheel mounted on an electric motor, and i want to stop the driver from going beyond a certain angle. i can read the torque applied by the driver, and the steering wheel angular velocity as well. how can i stop the steering wheel, without sending it harshely...
I am curious about the case where two electric or magnetic fields cancel each other out (I'm assuming this is possible). If a charged particle travels through the region where the cancellation exists, I am assuming the particle behaves as if no field exists. Does that area still have electric...
I am assuming the answer is NO. I realize that the electric field of any charged object has an energy density, but I was curious to know it that same field has it's own 'charge density' so to speak, and that it would have a small secondary electric field of it's own. This would imply that...
Hi.
I have physics homework that I don't understand. Hopefully, someone here can give me some advice. So, the homework goes like this:
Draw an electric circuit potential graph and find out the potential difference between points B and C. The two resistors have equal values.
Believe me or...
I understand that the energy of an electric field arises from the work put into gathering the electrons together to create the field. Bringing electrons close together requires energy because they naturally want to repel. This potential energy is stored in the field itself and the field has an...
Summary: In which scenario a current may exhibit alternated and continuous character together?
Hi All,
I would like to know in which scenario an electric current may exhibit alternated and continuous character?
Something like $$ I(t) = I_0 \sin (\omega t) + I_1 $$.
I tried to find it the following way but to no avail:
Let maximum value of ##\sigma## be ##S##
Now unfortunately, we do not have a maximum value for ##\dfrac{1}{r^2}## because the field point can be as close as we want to the arbitrary surface charge. (The field at a point on the surface is...