Electricity Definition and 999 Threads

Homework Statement A toaster, which uses 6 alkaline D batteries, must produce at least 900 W of thermal energy. D cell batteries have a capacity of about 5 Ah. How long can the batteries run the toaster? Homework Equations The Attempt at a Solution Well I know that Power is (J/s)...

hey everyone I am new to the site an new to physics ( bare with me if I am not as smart as some ) , =) ok, i have this friend who is world widly known for his work, but cut this short, he uses electricity an crystal an can do some out of the ordinary stuff with this he has been in numerous...

Homework Statement The potential caused by an array of charges in a region of space can be described by the equation V(x,y,z)=2x+xy+y2-xz2 volts, where all distances are measured in metres. If a charge of 2 mC is moved from the position r1=(1,2,0)m to r2=(3,1,0), calculate the resulting change...

Hi, Recently I've become interested in the possibility of using magnets to generate electricity, a "magnet motor" if you will. There are evidence of a lot of different attempts on the internet as well as a number of actual patents for these motors. When I say "magnet motor" I mean a...

If my memory serves me right I recall once someone said something like that in England or the UK electricity rates varies during 24-hour period. It costs more during nighttime than during daytime. Is this true? What is the rationale behind this? Please let me know. Thanks.

Hello, my name is Kevin and I going to be adding electricity to a barn about 1000ft away from my house. The barn will act as a second home and will need to be using around 2-10KWh. I figure it will never exceed 10KW per hour. I will be running it underground in heavy duty poly casing. My...

Homework Statement [PLAIN]http://img208.imageshack.us/img208/4577/physicso.jpg Homework Equations The Attempt at a Solution dont know how to do.. help please, how can i find that is 4V?

What are the factors that influence a generators output (efficiency?). Does the rotational speed of the magnets influence output? If so, by what magnitude can this be increased? ie. If a system is running at x rpm by what relation can the output be increased if the rotational speed is through...

From the attached photograph I have a continuing problem with what I would describe as “static electricity”. Shocks are being received from the rail system and also the aluminimum framing supporting the electrically operated window shutters. As indicated, the deck is a proprietary plastic...

hi , i was just wondering, if the sea is a good conductor of electricity, when thunder should strike it, won't electricity be conducted everywhere and everything dies in the sea? how far does electricity spread out? is there some sort of limiting factor? thanks!

Does anyone know where I can purchase the hardcover 1985 Electricity and Magnetism? Some schools, such as Caltech and MIT, still use the book; however, Caltech does not have it in their online bookstore and MIT lists an 09 edition (which I assume is an ebook?). Some copies are floating...

Homework Statement 2 parallel long, straight conductors lie on a smooth plane surface. 2 other parallel conductors rest on them at right angles so as to form a square of side 'a' initially. A uniform magnetic field B exists at right angles to the plane containing the conductors. Now they start...

This is my first post, and hopefully it's in the right section (my apologies if not!)...I have posted this on Answers, but there weren't any helpful responses there, so I though this might be a better crowd to ask. Ok, we were taught in our science (electricity) class that in order to reduce...

When current (DC) passed through a wire it creates a magnetic field around it, right? But if you placed magnets around that wire would they interact with the electricity flowing through the wire? If so, to what extent?

Maybe this should be posted in biology but it seems more like an electricity question to me: I've read that static electricity increases in the cold because of lower relative humidity. This seems to mean that it is more difficult for things to dissipate/ground their electric charge to the...

Building a wind simulator. Control amount of electricity?? I have about 20 6" fans that i'd like to mount to something in which I can control electricity to each fan and essentially simulate wind. I looked at light DMX controllers for DJ's and that would be perfect except the electricty...

Homework Statement Suppose electrons are sent through a double slit set up with a the slit width = 5.00nm and d the slit separation = 10.0nm. If the maximum current at the screen is 2.30μA, what is the current at the point .500 cm above the central maximum? Homework Equations dsinθ=mλ...

I'm not a physics major or anything (I'm actually a biochem major) but I was just wondering if the universal background radiation that keeps the universe (on average) a few degrees Kelvin warmer than absolute zero could possibly be enough to generate electricity. Essentially this minuscule...

im trying to learn about electricity (especially DC circuits) and having a tough time, the textbook i am using 'fundamentals of physics' by halliday,resnick, and walker doesn't do a very good job of explaining. does anyone know of any good resources that could help?

I'm taking E&M next semester, and the book we use is quite good at explaining concepts, but it only has 9-12 questions per chapter. I would like to do more practice problems. We used the same book for modern mechanics (it is a two-edition set, the first is mech and the second is E&M). Any...

Well I'm having a quiz coming up on Electricity/Circuits, and I want to get an A on it :smile:. However, regardless of the coursework I went through, I still have a few questions.*The Voltometer: http://img242.imageshack.us/img242/5664/circuitcopy.jpg It displays a voltage of 31.81 for the...

I am researching electric and magnetic fields, and so far from my understanding each electron produces its own electric field, negatively charged, and thus the atom has its own electric field, am I right so far? Some atoms have better current than others, this is related to the number of valence...

? I'm just curious. Also I'm having trouble with mechanics. I feel like i have no idea how to grasp fnet and calculating it. I also REALLY REALLY REALLY suck at drawing free body diagram. Math is a walk compared to physics which feels like a marathon. I'm actually not that great with math but...

During 4 hours one winter afternoon, when the outside temperature was 11° C, a house heated by electricity was kept at 23° C with the expenditure of 44 kwh (kilowatt·hours) of electric energy. (a) What was the average energy leakage in joules per second (watts) through the walls of the house to...

Homework Statement A solid sphere of radius R carries a volume charge density \rho = \rho_0e^{r/R}, where \rho_0 is a constant and r is the distance from the center. Find an expression for the electric field strength at the sphere's surface. Homework Equations \int\vec{E}.d\vec{A} =...

Our electric energy is provided by power-station,for example a water power station.My question is,the water power station doesn't produce electricity all the time,then what provide the voltage in our houses?Do they store the electricity?(It seem to be impossible)In addition,if it begins to...

Are the mathematical electrical laws as accurate as mechanics laws, if the input is perfect enough, or they're just good approximations?? I mean ohm's law and potential difference = electric field times length of wire (in wires), and alike laws.

Hello All, I am currently investigating domestic electricity use and whether or not the average (mean) per person use is affected by the number of people living in a household. I have monitoring data from several hundred households with household occupancies ranging from 1 to 6 people...

The fuse in my House continues to blow. The fuse rating is 20 amps. I can easily make the fuse so that it can't blow out but I know that might heat the wires in the wall if I draw too much current, and can cause an electrical fire. I am wondering, If I get a high grade durable power...

Back in my physics class in high school, we had a homework problem that stated a car had a circular hood emblem (pretty much a Mercedes-Benz hood star) and that when the car was in motion it would produce electricity due to magnetic waves going through it while it was in motion. I now own a...

Can electricity be positive instead of negative? What differences would it be? Can electricity be used to repel things?

http://www.facebook.com/#!/video/video.php?v=425444185921 Is there any merit to this? It seems like a commercial for "GS Filters" to me, but I've always considered the CBC fairly reputable.

Hi guys, I was answering some questions on my physics homework and I didn't understand why the answer was what it was... the first question was this: 1.) A hollow uncharged metal ball hangs from a silk thread. A glass rod has been charged by rubbing with rayon. When it is brought close to...

Is it possible for electricity to jump a vacuum gap? If so, what is it called when that happens?

Homework Statement A battery has an emf=6V. The battery is connected in series with an ammeter and a voltmeter. If a certain resistor is connected in parallel with the voltmeter reading decreases by a factor of 3, and the ammeter reading increases by a factor of 3. What is the INITIAL READING...

Stop electricity? Is it possible to stop electricity by stoping electrons with the magnetic field?

Homework Statement [PLAIN]http://img186.imageshack.us/img186/6260/physicsquestion.jpg Homework Equations Not sure...? The Attempt at a Solution I believe the answer should be A or B. I'm thinking the live and Earth wires will form a complete circuit. Since there is very...

Direct to the point, Is it possible to convert Kinetic Energy into an Electricity or Electrical Energy?? How?? Without using...like wind, hydro, and etc...

In news stories about the countries suffering from energy crisis it is said that, let's say, the electricity shortfall has reached 3,000 MW while the generation is 5,000 MW and demand 8,000 MW. Watt is used for rate of energy, energy flow per unit time. Are they talking about the shortfall in...

hi friends, i came across this piece of news... "Until 2010, no solar sails had been successfully used in space as primary propulsion systems. On 21 May 2010, the Japan Aerospace Exploration Agency (JAXA) launched the “IKAROS” (Interplanetary Kite-craft Accelerated by Radiation Of the Sun)...

Homework Statement the problem is attached to this post Homework Equations Req=1/R1+1/R2+... for parallel and Req.=R1+R2+... for series... Kirchoff's law for Current and Potential to be applied The Attempt at a Solution completely lost ... pls help

I've been reading about static electricity, and I'm starting to get a handle on how it works. I have a big question; static electricity always seems to make things stick and what not, but is there such thing as static electricity repulsing?

Well I guess it's pretty simple, I know E = IR, but I've been thinking of some situations lately that have been confusing me so I decided to ask here. The first one is how does a high voltage stun gun not create high currents? The highest I've seen is 4.5 million volts. I think they simply...

In the situation shown in the figure a particle having charge q is executing simple harmonic motion of amplitude A and time period T in front of a CONDUCTING EARTHED SPHERE of radius R. The reading of the voltmeter when the charge particle is at its mean position(at a distance r from the...

Homework Statement 1. Rod A has negative charge and is used to induct rod B. Rod C then charged by touching it with B. The charge on C is… a. Neutral b. Positive c. Negative d. Undetermined2. a. Plastic comb that we hold can be charged by rubbing. Why a copper can’t be charged when we are...

Homework Statement 1.a ball is attracted to both positive and negative charge. state whether the ball has negative, positive, or no charge 2.why does electroscope use gold for the "leaf"?can others metal be used? 3.http://www.sciencebyjones.com/induction.gif i do not understand that...

Is it possible to convert electricity into propulsion force? My friends and I are discussing about this subject. Is it possible to build a device which can convert electricity into propulsion force? just so you know, we have incessant electricity produced by solar cells and if that...

A month ago or so, an idea popped into my head. Here it is in a nutshell: If you send a space device or ship in an orbit that takes it to do gravity assists over and over again to increase its velocity to generate lots of kinetic energy. If you do that, how much kinetic energy would be created...

Hi all I'm a complete newbie to the subject of electricity and trying to wrap my head round it. To be more precise, I'm trying to build a mental model for myself that accurately predicts what goes on in circuits. I've read several accounts that suggest a model based on the flow of...