Electricity Definition and 999 Threads

I got the answer by comparing I2R of the circuit with resistor R but why do i have to use R/2 for power of resistor R?( P= (0.5I)^2 (R/2)) I know its parallel to Resistor Q but i want to find the power of that component so shouldn't it be P= (0.5I)^2 (R) instead?

Homework Statement Positive charge +Q is distributed uniformly along the +x axis from x=0 to x=a. Negative charge - Q is distributed uniformly along the +x axis from x=0 to x=-a. A positive point q lies on the positive y axis, a distance y from the origin. Find the force (mag and dir.) that...

I had some trouble reconciling signs while attempting to teach electricity to my students here. The topic is electric potential, potential energy, electric force, electric field, and work. After much thought - several hours - I have finally come up with a presentation that solves the issues...

A tiny sphere of mass 7.70 µg and charge −2.80 nC is initially at a distance of 1.74 µm from a fixed charge of +9.25 nC. (a) If the 7.70-µg sphere is released from rest, find its kinetic energy when it is 0.500 µm from the fixed charge. (b) If the 7.70-µg sphere is released from rest, find...

Can one get electric shock by touching only one terminal of AC generator ?

Two main methods of generating electricity that I know off, and that are common: 1 ) Magnets & Coils 2 ) Solar cells. The only two methods! What do you all think are the possibile future methods? Are we close? Is there something you recommend me of look at? I was just thinking of how...

helllo ALLLLLL my question in Ac single phase without earth only one phase live and one neutral why we say that live line would kill but neutral won't kill isn't neutral carry current for return "same live current"

I wasn't really sure where to post this, but I am currently taking a second year Electricity and Magnetism course this term. I want to be able to do well in this course in order to keep my GPA up, but I don't have a particular interest in this class and the prof flies through the material at a...

Homework Statement please cheack my answears and see if they are right, please help me solve the wrong ones thankyou ! (1)if you were to expend 10 J of work to push a 1 C charge against an electric field , what would be its change of Voltage ? voltage = electric potential energy /...

I just need some help and verification on some of these questions from my physics textbook, this chapter also covers electroscope. 1) If you charge a pocket comb with a silk, how can you determine if the comb is positively or negatively charged? The attempt at a solution: We can use an...

Hi I am "new" here. Uh so the speed of electricity in copper is about 95-97% of the speed of light. Now to clarify. That is the speed it uses (say DC) from one place to another. And the reason for the loses in speed is due to the electrons having mass. So when one bumps the other the...

Author: Edward Purcell Title: Electricity and Magnetism Amazon Link: https://www.amazon.com/dp/1107013607/?tag=pfamazon01-20 Prerequisities: Freshman mechanics. A year of calculus. Purcell introduces vector calculus from scratch, but most students who hadn't already had vector calc would...

Different materials emit different frequencies of radiation when heated by a source of heat such as electricity. Examples include gases and solid filaments that emit infrared, visible and ultraviolet radiation, and the scheelite calcium tungstate filaments used to produce x-rays in fluoroscopes...

Hey. So I switched from ChemE to Engineering-physics (I guess I followed my hearth here, instead of my head), and this entails I will have to take a course in Electricity and Magnetism this semester. During the previous one, the Engineering-physics guys took a course in mechanical physics, and...

Hello, Is there any difference between 50/60 AC current and a 50/60 Hz photon stream/electromagnetic wave propagating through a medium ?? Regards, Hex

Electricity & Magnetism, Thermo + Quantum Mechanics? Hi! I've recently completed my first semester of college and it's offered me some insights. For example... the world is three-dimensional and, as such, multidimensional calculus exists! I managed to somehow survive Honors Mechanics but it...

Homework Statement I've been set an assignment and I'm struggling with one question in particular: Homework Equations 'Use the following data and plot the graphs for a point charge' 'Plot graph of E against r^2. Interpret the graph to describe electric field strength and electric...

Is it possible to use an electrical current (from mains electricity) to create static electricity on a conductive surface (that is not earthed) without the two coming into direct contact? See attached image.

Electricity has been a mysterious entity plaguing my mind since last year when I learned about it in class. I am unable to understand why electrons move the way they do when a circuit is formed, nor what is the driving force to make them do so (which is voltage difference, and I don't understand...

http://www.ted.com/talks/eric_giler_demos_wireless_electricity.html In this video, I have two questions: 1) Why have a capacitor as part of the two circuits? Is it so no actual current flows around the coils, that's all I could come up with. 2) In the picture he shows of the two...

Homework Statement A proton just floating in a field in a between two boards (g=9,82 m/s^2) What is the voltage U? distance d = 2 m charge for protone Q = 1,602*10^-19Homework Equations E = F/Q E = U/dThe Attempt at a Solution I've tried two different ways of which I don't know is correct...

What makes Electricity and Magnetism a "unified" force? I'm taking upper level Electromagnetism and we've dealt with the various formulas dealing with electricity and magnetism. It seems to me that we are still largely dealing with them separately. In that, I mean we have a thing called a...

Homework Statement We have a charge Q and it's h metres far from the flat surface. Find the force with which acts on the Q charge by the surface The answer is: F=kQ2/4h2 i couldn't get it, please help me. Homework Equations The Attempt at a Solution

Why do they use two different switches, one for the low voltage source and another for the high voltage source, to operate electric motors such as lift machines?

Occasionally saw this on internet, do anyone think this works? "Hi. This is about an idea of generating electricity by gravitational force. Attached please the basic concept of the idea. The idea consists of two major parts. The first part of the system makes use of electrolysis of...

Refer to my third post :) clearer and the picture in my second post

Layden jar questions? :) And some static electricity questions.?? Hello. I'm making a layden jar and i am kinda changing some details in it. and i want to ask if those will affect anything in the performance and if it's shocks can be lethal.. http://postimage.org/image/s9xqthylt/...

Hi, I learned that, when a field does work on something, like when an electric field does work on an electron, it loses potential energy -- much like when a ball falls from a height (gravity is doing work on it) it loses potential energy. Hence, as an electron flows from the negative to...

can we use fast moving hydrogen ions in long glass tube which are practically vacuum for transfer of electricity. the hydrogen ions are produced by consuming energy and when they reach the destination(electrode) they form hydrogen gas and give electricity.

"In fine weather, the electric potential increases with altitude at about 30 volts per foot (100 V/m)...." what hinders its practical application as a source of power, as a battery?

Ok, I"m from New Jersey, and as you may have heard we've been hit pretty bad. ...After spending 3 days in the dark and cold... I've had some time to ponder. My question is a very basic one. I know that many phone lines and wires are put underground. That's why you see the Bell logo on many...

Did anyone see this? I just read about it. I don't watch TV, so I have no idea what's going on in the world. The internet is pretty good, but it didn't inform me about this. I just read the Wikipedia article and it said "An ambulance transported him to a hospital where an EKG showed that the...

Can anyone tell me some fluids that are electrically charged? And if it would be safe for, let's say, a fly to consume?

Can anybody help me with this problem? A spherical conductor of radius a is located at the center of a spherical conducting shell of inner radius b. The space between the inner conductor and and conducting shell is filled with an insulator of resistivity rho. A thin wire is passed through...

The title is pretty self-explanatory. I know the speed of the falling magnet is much slower in a copper pipe, but since the magnetic field moves, is there still some electricity generated in the process, even though the speed isn't great? Thanks!

Now i am a refregration apprentice so by know means am i qualified or mabe have no idea what i am talking. now i belief that by heating a gas you increase the pressure it is putting on the object contianing it and by cooling it you reduce that pressure. So is it possible to cool the gas at...

Is there any type of liquid or solid, or any material that will expand with the addition of electricity, or vice versa?

I'm in grade 11 and we still haven't looked into how electricity really flows. Right now all we're told is that the electrons move from atom to atom, the quantity of electrons dictates the current (in coulombs, however you spell that), and the amount of energy in each electron is the voltage...

Homework Statement Given two batteries in parallel, one of 10V and 5Ω, and the other of 5V and 2Ω, which is attached to a 3Ω resistor, find the current that flows from the 10V battery, if the system described above is connected to a 20 resistor. Homework Equations Kirchhoff's two laws...

Is it possible to recharge a device, say of 15-2by converting the magnetic field is produced by electricity flow through any random wire anywhere? This is for an important exhibition and so i request an in depth answer which helps me figure out the hows and whats... thanx

Hello, Firstly i am new here ( not offering an excuse) and an on and off lurker to this awesome forum. I am trying my best to fit into the established rules ,sorry if i broke any inadvertently. If kinetic and potential energy represent the same things why are there entities representing the...

I'm new to the forum so I'm sorry if this question is posted in the wrong place. I have been doing some research on magnetic motors and they seem possible, but I am not talking about the fixed magnet motors where all of the magnets stay in the same position. I found this video where there is a...

Thinking of a restrictive pipe as an analogy of a resistor, which converts electrical energy to heat, would a pipe demonstrate a rise in temperature related to the loss of energy in the water, . (theoretically - and assuming conditions which did not have other influences - so water at ambient...

Hey guys I'm a new member and I will be mostly asking questions :P Anyways ... Physics subjects in my school are about electricity now and my teachers aren't very good, so I can't clearly understand what they're saying. To get to the bottom line, our lesson was about electrons and...

Can electrical currents in a wire affect each other? Imagine racecars and how they affect each other in a race for this. Reply in simple english please.

Does a ceiling fan consume more electicity at higher speeds or is the same at all speeds?

Homework Statement If lightning strikes a tree such that there is the same current through it as there was through the lightning conductor, then a much larger potential difference exists between top and bottom of the tree. Explain why this is so. The Attempt at a Solution Is this...

Since the instructor of my course doesn't use a textbook and just teaches based off his notes, what would be a good text to supplement my learning (when asked what he recomends, he just said find something in the library). Does electrodynamics = electricty and magnetism? I've heard this one is...

How do you calculate cost per unit of electricity over a certain time that a generator produces?

I am going into my fall semester of E&M and am trying to decide upon a topic to write about for an honors project. I have not taken an E&M course yet so it is difficult for me to really find which topics are too advanced scientifically or mathematically at this point. So far I have taken a...