Electricity Definition and 999 Threads

The attempt at a solution (Assuming the components are in series of this order: resistor, inductor, capacitor So I know that the phases are not in sync, that as the voltage oscillates the voltage across each component in the circuit is different. At the peak voltage aka peak current the voltage...

The Faraday's law and Lenz's law together give you, $$\xi = -\frac{\partial\phi_B}{\phi t}$$ or put another way,$$\vec{\nabla} \times \vec{E} = -\frac{\partial \vec{B}}{\partial t}$$. My question, I am just asking to make sure, the spatial dependence of ##\vec \nabla \times \vec E## will be the...

Hi, I am taking GRE Physics this year and I am preparing from Conquering GRE Physics book and I have covered everything in that book on Electricity and Magnetism (yet to study Optics and Waves). My question: How much from Griffith Electrodynamics book do I need to study? Or is the material in...

A post, each which connected without a wire, is it possible in a brief future?

1. Problem Statement: Find positions on the x-axis for the charges Q1 = -1 C and Q2 = +3 C so that the electric field is zero at x = 0. Homework Equations :[/B] I'm thinking I need to use Coulomb's law for this one. I'm just having trouble figuring out where to start. Coulomb's states E=kQ/r^2...

I know that the right hand rule applies for induced currents, and the left hand rule is for motors, but why? It doesn't seem to connect with any other physics laws and is very counter-intuitive that the current will flow in one direction rather than the opposite direction if both are...

I read somewhere PE=KE, how? It mean we can get transfer 100% PE to KE and KE to Joule Please anyone can explain? If I throw mass of 1000kg from 50 meters height can I get energy equal to Pe=mgh = 1000*9.81*50=490500 Joule? It mean 490500Kn = 490500watt= 490.50Kw. Is it possible to to get this...

Why does my laptop's screen refresh every time I bring a metal object (any size) to my electric lighter? -Happens when I am 1 foot away from the laptop -1 foot away from the external monitor's wires (HDMI & power) 1. Video footage (MUST WATCH) NOTE: the laptop screen also flickers a bit NOTE...

Hi...Here is a GIF of some electrical explosions that I recorded with my full spectrum camera. These power lines supply power to a neighboring county so it didn't affect my area. In the upper atmosphere we see something similar in Transient Luminous Events (TLEs). In the case of the blue in Blue...

Homework Statement Homework Equations gauss law q=charge on sphere Q=total charge enclosed by gaussian surface Q=alpha/r x (4/3 pi r^3-4/3 pi R^3) + q The Attempt at a Solution EA=Q/ε[/B] E=Q/(Aε) now for E to be independent of r, alpha/r x 4/3 pi r^3 + q = 1/(4)(pi)(r^2) alpha x 4/3...

Hi guys i have a question i want an answer to let say i have an object that is negatively charged and another object positively charge and i connected them with a wires to a light bulb will they generate electricity and the object never lose their charge let's they they have unlimited charges.

Homework Statement Homework Equations F = k(q1q1/r^2) K = (mv^2)/2 The Attempt at a Solution I got number 18 easy enough, number 19 seems simple but I'm not getting the right answer. I'm calculating Force exerted by each charge on the new charge using F = k(q1q1/r^2) for the three charges...

We're all told how circuits have to be closed and loop back to be able to have the electrons flowing and give things power, so is that the reason most outlet charges have two wires connected? If so, why are phone chargers only one wire, and how are they so thin? Thanks!

Homework Statement Homework EquationsThe Attempt at a Solution I often do circuit. But still there is always stuff i don't get.. I was asked to find 1) I1 I2 I3 immidiately after S closed 2) I1 I2 I3 after sufficient of time 3) I1 I2 I3 immidiately after S opened Just give me clue please...

Homework Statement A circuit contains a capacitor of capacitance C, a power supply of emf E, two resistors of resistances R1 and R2 , and a switch S2 . Resistor R1 is in series with the power supply and R2 is in parallel with the capacitor and the power supply. S2 switches the branch that...

Sorry if this is a bad question, but would lower costs to produce electricity (e.g. hydroelectricity instead of solar) bring down the overall costs for us consumers? Also, if there is any reading material or website on this topic, that would be really great too! Thanks!

Can a positively charged and negatively charged object charge by conducting? If so, is it possible to make a neutral charge again?

My textbook states: "The magnitude of charge of the electron or proton is a natural unit of charge." and then has an explanation that follows. It states, "...The charge on any macroscopic body is always either zero or an integer multiple (negative or positive) of the electron charge." Here is...

Homework Statement A current I flows along a wire toward a point charge, causing the charge to increase with time. Consider a spherical surface S centred at the charge, with a tiny hole where the wire is – see figure below. The circumference C of this hole is the boundary of the surface S...

The circles are referring to independent voltage or current sources, which maintain the same current/voltage regardless of the rest of the circuit. I'm confused because power delivered means they want the value of the "negative" power, which would mean only i*v1 would be the only power...

Homework Statement A constant voltage source V with internal resistance r is connected to a load resistor R. The dissipated power by the resistor R is P=RV^2/(R+r)^2. Show that the maximum power dissipated by the resistor R is achieved when R = r. The maximum of P with respect to R is achieved...

Find the electric field strength at point B between two charges shown below: Given/Known Values q1 = 4.0×10-6 C r1 = 40 cm = 0.4 m (Distance from q1 to point B) q2 = -1.0×10-6 C r2 = 30 cm = 0.3 m (Distance from q2 to point B) k = 9.0×109 Nm2/C2 Equations Electric Force: FE = (k⋅q1⋅q2)/r2...

Homework Statement Suppose a 120 micro-farad capacitor from a camera flash unit retains voltage of 210 V when an unwary student removes it from the camera. If the student accidentally touches the two terminals with his hands, and if the resistance of his body between his hands is 1.8...

Hi I have a question about electric potential! Since the negative sign isn't used in U=qV, and a-b is used for subscripts, then that takes care of the negative. But what about using U=-qV? An online lecturer uses U=-qV, while my textbook uses U=qV and then uses -qV to explain the force used to...

For starters, it’s like 11 pm and I just had to ask this question so please bear with me if what I’m asking is confusing. So my question is what is electricity made out of. Atom wise. I know I probably could’ve Googled this but I figured why not ask this for everyone’s benefit. I figured hey...

Dr Marty Jopson leads us through the story of electricity in a show buzzing with demonstrations. Have we tamed electricity? From the Ancient Greeks to Faraday’s genius, this show puts the awesome back into electricity.

Why does current produce a static magnetic field, but a static magnetic field doesn't produce current? Specifically, why is one true, but the inverse not true? I can accept that each rule individually is just how the universe works... but it sounds so contradictory when I examine both together...

Hi there :-) I got that crazy idea to make regeneration of electricity on my e-bike when the bike runs downhill, by using its motor as a generator when the throttle is off. My e-bike is custom made by myself. The motor is located in the front wheel hub, and it provides 7 Volt 3-phase voltage...

Can someone explain the math of how potential energy travels from higher potential energy to lower potential energy (PE) along a uniform electric field? I understand that in order for the point charge to move, gaining kinetic energy, it will lose potential energy. But using the equation...

Is it possible to design an unpowered antenna, (possibly some kind of RLC circuit) which will receive a radio wave at a particular frequency and then re-emit it at a lower frequency?

I have a RC circuit which also includes a battery, the capacitor has some charge initially before we put all the components in the circuit. Now as I connect all of them then charge will start to flow, but wheather this charge will be the sum of initial charge on the capacitor and the new charge...

My application is for textile spinning machine where Rubber roller is running at a speed of 10000 rpm. Another rubber (stationary)is rubbing on the rubber roller surface. In this case cotton fibers are sticking on the surface of stationary rubber due to static electricity and over the period it...

I do apologize if this is considered against the general discussion rules. I'd really like to get the opinion of individuals of an intellectual nature. I remember a recent discussion with a few family members on the topic of building infrastructure (roads) that generates electricity utilizing...

In the making of firework explosives, the explosive mixtures are handled with great care to avoid static electricity induced detonation of the explosives. Is it a good idea that they store the explosives in a plastic container - isn't there a risk of static buildup that could detonate the...

Homework Statement Im doing a project on Emf and internal resistance. I'm just trying to understand what the load would be and where I would put the positive and negative pens on the schematic to find the load. Homework Equations Terminal Voltage would be what I have in the image above...

Homework Statement 1. A sinusoidal source with RMS voltage V = 11Volts across a resistor R = 50Ohms, determine the dBm value. Hint: you will first have to determine the power delivered and then check the formula for dBm calculations. 2. A type of coaxial cable has a loss of 12dB/100m at some...

Does EMI filter still work if you live near a base station which produces dirty electricity? Or EMI filter only filter the dirty electricity which would have been generated from your power circuit if w/o EMI filter?

Homework Statement Hey guys, here is a question that I have trouble with, it is a past paper question in the AS physics syllabus /Users/peterrong/Desktop/Screen Shot 2017-10-10 at 3.57.12 PM.png Homework Equations The Attempt at a Solution I have attempted using kirchhoff's laws, but the...

Hello, all! I found several sources which say that humanity could be in trouble because of solar flares! Scientists said that the Earth could be hit by solar flare within the next 100 years! Current costs of repair in the US could be up to 2.5 trillion dollars! It seems like Sun will punish...

Homework Statement In a lab experiment we measured the potential at different points within a cylindrical capacitor electric field modeling plate thing (apparently that's the best I could do to translate that into English). The positive electrode was connected in the middle and the negative...

Homework Statement The current source and voltage source in the circuit shown in the Figure below are connected in parallel so that they both have the same voltage, vs. The current source and voltage source are also connected in series so that they both have the same current, is. Suppose that...

Homework Statement 1. An RC filter is constructed by modifying a voltage divider. The top resistor R1 = 3kOhms remains the same but the bottom resistor R2 is replaced by a capacitor C = 8nFarads. Determine the corner frequency fc for this filter in kHertz. 2. For an RLC circuit R = 12.4...

If take a simple dc motor and connect the negative side to let's say a insulated metal plate. The other side directly to ground and you then turn the shaft of the motor. Would you force all of the free (loosely using all) electrons in the insulated metal plate through the motor to ground giving...

Homework Statement [/B] 1. Using the Schematic of a 555 in astable mode from the Wikipedia entry on '555 Timer IC," resistor R1 = 8 kOhms and capacitor C = 3 micro-Farads. Determine the value of R2 so that the output duty cycle is D = 0.7. Note that D is not expressed as a percentage here for...

Homework Statement I've seen many books writing the cosine rule like this: a^2 = b^2 + c^2 - 2bc cos A My electricity textbook for an electric field in a point between two charges says this: E resultant = root[E1^2 + E2^2 + 2*E1*E2*cos(angle between E1 and E2)] In the first equation it is -2...

Hello, The issue of climate change and energy has been in the news for a long time. But are electric, chemical or renewable sources really more environmentally friendly than fossil fuels? Fossil fuels need to be burned, which produces CO2, which retains the heat from escaping our atmosphere, so...

Homework Statement [/B] Hey everyone, I recently got two problems on capacitance and inductance and need some help on them. Here are the two problems: 1. A Royal Red Robin Burger contains 1230 food calories. Also, more that the daily requirement for protein, fat, sodium ..., even without fries...

I know that batteries move electrons therefore creating a current when there is a load. So if a battery is just for moving electrons, where do the electrons come from? Are electrons just in everything and by moving them you create electricity? If that were the case, why did I read somewhere that...

Hi! I'm curious to know, whether it is possible to produce electricity by moving a piece of metal over a magnet (i.e a immobile magnet and a moving piece of metal close to the magnet), and how this would be done in practice.

Homework Statement (see my attached photo to better understand where I am coming from!) So after some research, I've discovered that the current at different points in a simple series circuit is supposed to be the same value, and that the voltage is supposed to be different values. I...