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 : [/B]Given the circuit diagram, find the equivalent resistance between points P and Q. Homework Equations : [/B]ΔVloop = 0, ΔIjunction = 0 and V = IRThe Attempt at a Solution : [/B]Eliminating the wires with no resistors and solving for resistance gives me the answer as...
Homework Statement
You have a new unknown material. You want to get a rough approximation as to the location of the unknown material on the electrostatic series. You only have two tools at your disposal; some wax and a charge detector. Design an experiment (procedure) that will help you...
Hey, my teacher gave us this scenario and I didn't really understand how he went about doing this. I was wondering if there was someone who could shed some light. Thanks!
You have a new material in front of you titled Material Gamma. You want to get a very rough
approximation as to the...
So since a lot of electricity ran through a coil creates a magnetic field as sown in one of faradays most famous experiment what if the coil was a superconductor and will it improve the magnetic field and will it make one at all?
In a discussion about lightning destroying electronics on sailboats the issue of controlling lightning came up. One member (Baluncore) proposed that lightning is completely predictable. I've been taught that lightning is somewhat random.
To me, random implies non-linear equations with sensitive...
Hi, I'm looking for some great books clearly explaining how electricity, magnetism and electromagnetism Works.
I'm also looking for some books describing how it was discovered and what experiments have been performed in discovering how it Works,.
So Far I've looked at
Electromagnetism...
Hi there!
as wee all know V=IR
v= potential difference
I=current
R=resistance
so => I=V/R
and somehow we make Resistance almost equal to 0
then I=V/0
will I become infinity?
or what?
what will happen?
Please clear every situation to me?
Power Source at 6.0V
a) Voltage drop across the parallel branch of the circuit: 0.25V
b) Voltage drop across the light bulb connected in parallel: 0.25V
c) Voltage drop across the light bulb connected in series: 0.5V
2) How would you measure the current through the entire circuit: By putting...
A thin metallic spherical shell contains a charge Q over it. point charge +q is placed in side the shell at point T separated from the centre by a distance a. Another point charge q1 is placed outside the shell at a distance b from the centre find the electric field at the centre due to the...
Homework Statement
A capacitor is charged to V = 5 kV.
A wire is then connected to one plate and is slowly connected to the other. Before actually touching the plate, a spark of length l = 1 cm shoots from the wire to the plate. Using this information, estimate the dielectric breakdown of air...
It is my general understanding that according to KCL, current requires a closed loop to flow in DC. However, this is apparently not true in AC; current doesn't needa closed loop to flow.
I have drawn a circuit below which causes confusion:
C1 is a charge capacitor, R1 is a resistor, I1 an...
If drift velocity of electrons changes in AC, how does electricity flow through a circuit to then lose potential energy to the devices in the circuit?
Also considering the change in direction, does that mean that the live wire and neutral wire also switch roles in AC mains? I am very confused...
Homework Statement
The following figure shows a potential divider circuit made up of a LDR and a variable resistor R. It is used to activate a buzzer circuit which sounds only at 2.6V and above. The resistance of the variable resistor varies from 100ohm to 10kohm while the resistance of the LDR...
I'm not learning physics in English, so terminolgy might be wrong.
1. Homework Statement
How does this circuit function? Where do the electricty flow?
Homework Equations
No equations
The Attempt at a Solution
Not sure what to put here?
My question is basically how it work. As far as I know...
Homework Statement
The ammeter reads 5.0A. Find I1, I2, and ε
Homework Equations
ΔV=IR
The Attempt at a Solution
I've never dealt with ammeters before so I'm very confused.
To start, I tried breaking this into loops, and then used Kirchhoff's Law.
I started with the left side, since I...
Please note, this is a question, and not a guide or instructional article.
While learning about electrical-engineering, I realized that I did not really know what electricity was.
So I decided to read into it, and what I found was quite confusing. A lot of articles I read conflicted with my...
Homework Statement
Consider a 2N3904 NPN transistor in a circuit. Treat the lightbulb as a 100 ohm resistor. For different values of R, what is the current through the lightbulb? Enter two digits rounded to the nearest 0.1 amps.
If R=500 ohms, the current through the lightbulb is:
If R=5...
I am supposed to graduate next year but I just realized I have left Electricity and Magnetism off of my schedule. I'm afraid to add it because I feel like I am already taking enough and I am wondering if instead it is common or likely to just take the undergrad elective in graduate school. I...
The related question says:[PLAIN]http://
The capacitor 1 is initially charged by having the flying lead attached to point C. Then, the flying lead is moved to point D. Capacitor 1 discharges.
C2 has no charge intially.
When the flying lead is attached to D, which one of these statements is...
At this stage of my education there's a lot of things that we're just supposed to accept and roll with it. Last year electricity was pretty much Ohm's law and Kirchoff's rules, now I've done electric fields so I'd like to understand it in more detail. Let's consider a simple circuit with a...
Homework Statement
A 3-V battery of internal resistance 1Ω is joined to a sliding wire of length 100 cm and resistance 5 Ω . A voltmeter , which takes negligible current , is connected across 60 cm length of the wire . (a) What is the reading of the voltmeter ? (b) If the reistance of the...
I am currently working on a project for school where we need to create an alternative source of energy for a country. My country is Italy and I thought of the idea of utilizing the CO2 emissions from the fermentation in wine making processes. I know you can use CO2 emissions to create more...
If there is only one resistor, the voltage drop is equal to the potential of the positive terminal. The voltage drop across more than one resistor is directly proportional to the value of each resistor. But the total drop in potential difference must be equal to the potential of the positive...
Homework Statement
There is an infinite 2D mesh of conducting wire. Resistance between any two consecutive junctions is R. What is the equivalent resistance between any two consecutive junctions?
Homework EquationsThe Attempt at a Solution
Every junction is connected to four points and one of...
Why flowing current in wire creat magnetic field...if anybody say this is because of spin quantum number,...
So i just want to say spin quantum number is because of wave nature of electron.i just want to know what effect of dual nature of electron on magnetic field.:rolleyes:
Hi, so I've just started learning about physics and I get the gist of most of it. I understand motion, torque, energy, light, radioactivity. But there is one topic that absolutely stumps me. Electricity.
Can someone explain to an absolute moron like me what it is? It seems like everyone around...
Based on what I have gathered so far, I don't see why a micro-scale generator wouldn't work, but then again I am a geographer with modest calculus skills. My biggest problem is not knowing how much I don't know, and I am hoping some kind and wise soul on PF can cure my ignorance.
Let's say I...
Let's say I got a nerve electrical signal running in one direction "/" and when the signal gets to the middle of that path I poll for that signal and shoots out a electrical current in the other direction "\" not the electrochemical current, so now I have a shape that looks like "y", does it...
We Know that in conductive Solids there are lots of free electrons available & they drift when electric field is applied. Their drift velocity is in the range of mm/sec to cm/sec. Now if we consider any conductive liquid which is flowing & we connect the electrodes in such fashion that the flow...
I just did a thermoelectric generator from seebeck plate. And when temperature increases, the plate's resistance increases from 12 ohms to 8 M ohms. Why is that and how todeal with it??
The cell can provide conatant emf ε and initial charge of capacitor is zero.
Now current through resistor initially is zero and increases. But the potential difference across the capacitor is always a constant with magnitude ε.
then ##\frac{q(t)}{C}=E##
So ##q(t)=CE## which implies q is constant...
I was wondering, is it possible to charge oneself with static to an extent that would be lethal or even damaging to a significant extent beyond the usual discomfort?
What are the governing calculations? Instead of the usual carpets would any other materials in an exceedingly dry climate give...
Homework Statement
Calculate the current in the capacitor shown in the figure below if the voltage input is V(t) = 29cos(377t-30) V, C = 1 micro Farad
Homework Equations
i = C dv/dt
The Attempt at a Solution
I essentially differntiate V(t) and multiply by 1 * 10^-6. I then get a negative...
Hi guys,
I'm working on a school project and I don't know a lot about electricity, so here is my question. Let's say that I have two small 6V DC generators, and I need an output of 12V (I can not use a 12V DC generator because space is limited, the two 6V fit perfectly) is there a way to...
, 2.5 amps of current is drawn from the battery . Does that means that the total current for all of the bulbs are 2.5 amps ? and can i say , on bulb has 0.5 amps of current flow (given that the 5 bulbs are identical)? thanks in advance.
Hi all,
I'm trying to generate enough current using a solenoid to intermittently power an LED. My plan is to buy some enameled copper wire and wind it around pipe. This will be my solenoid. Then, magnets will be pulled through the pipe on string or what-not and, by Faraday's Law of Induction...
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i want to build an electromagnet which can attract small iron pieces(2-3 mm long) at a distance of 10 cm from the magnet.I am using 24 awg. magnet wire.Please help .answer these questions -
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2)How much current
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4)...
Hello,
For a future development, Me and a friend of mine were talking about some thruster technology and we wondered if it was possible to transform electricity to matter to create some sort of chemical thruster or using the matter to create an ion and use it as the thrust. well at least...
Homework Statement
In the figure mA = mB = 1kg . Block A is neutral while qB = -1C, sizes of A and B are negligible. B is released from rest at a distance 1.8m from A . Initially springs is neither compressed nor elongated.
https://brilliant.org/discussions/thread/amplitude-of-oscillation/
View...
1.Is Quantization of electricity is helpful for increasing Voltage?
2. Can I use galvanometer in capacitor to increase it's capacitance?
Thank u , I am new to this forum.I want to ameliorate my knowledge in electrical engineering.
hi,
my name is suli, 16 year old from living in the U.S.
I want to one day become as decent an engineer as i can, i hope that this site will help me learn more about the rules that govern the universe.
i am especially interested in electronics, maybe its because of iron man ? dunno...
well...
hello
I wonder if electrifying a metal will increase its reactivity with other substances or not
the mechanism I imagine it to be the increased movement of valence electrons, perhaps an energy excitation of them, so that they react more with substrate
is this true?
thanks
Here is a picture of a circuit:
I have two questions:
(1) Are all resistors connected in one of two ways? I.e., resistors can be connected in parallel and in series, but is it possible for them to be connected as NOT parllel and NOT series? For instance, the two circled resistors don't seem...
Changing the potential energy of water is frequently used as a means of storing excess renewable energy when it is not needed and using it when it is needed. An electrically-powered pump with efficiency 62 % raises a 10 kg mass of water a height of 10 m. The water is subsequently allowed to...
Homework Statement
Homework Equations
V=IR[/B]
From my textbook:
If the circuit contains both independent and dependent sources, the open‐circuit terminals are shorted and the short‐circuit current between these terminals is determined. The ratio of the open‐circuit voltage to the...
I know very little about electricity, but I'm trying to understand it better. I'm trying to wrap my head around something- I have heard it said that, "the flow of electricity through a circuit is due to the movement of electrons". While this explanation sounds simple enough, I have some...