Electrical energy Definition and 124 Threads

I'm sorry to be annoying on this forum, I am new to the physics world! I am an undergrad taking physics I but am also doing a directed study on acoustical physics, sort of. I just need to write a paper on something along the lines of acoustics and their uses in communicative devices like...

Is there any known method to convert straight into electrical energy? without all that 'steam' part? xD

Hi I am thinking of ways how to transfer electricity so that I can separate the phase magnetically or otherwise, Ok we all know transformer is one way to do it but it's big with mains frequency, other would be pulsed DC in an smps , but that's is already a very tried idea, is there any other way...

Sorry if the title is slightly misleading, but I'm having a hard time trying to develop a better understanding of electric current and electrical energy. Basically, I understand that, say for example, a potential difference across a circuit creates an electric field, which in turn causes the...

I have to calculate the thermodynamic efficiency of a power station. I have to assume the cooling towers maintain 70 degrees C and hence the amount of electrical energy (in J) from one mole of methan. I've been given the enthalpy of combustion of Methane. I know the thermo efficiency is (sum of...

Greetings. My friends and I are working on a "mechanical to electrical energy" project, and we're facing a huge problem with the basic design of our system. Basically, we wanted to make use of a system where a person would 'step on' a pedal or a tile, whatever you may want to call it, which...

What happens with the electrical energy within the body when we die? I've been thinking about this for weeks, and even though I'm not that great at it, I find anything scientific interesting. I truly have compulsive documentary watching disorder :p I watch new ones every day, and if I don't...

When transferring electricity from a generator to a factory or anything we would use a transformer to step up the voltage right? As P=VI and P is constant in the primary and secondary transformers (ideal case), with an increased V as compared to the primary transformer it will in turn result in...

Hello, I was watching national geographic from 1 or 2 weeks, and they illustrated a way to produce electrical energy from surf. I will try to explain the principle: 1- They brought a cylinder, and attached to it a turbine which is designed to rotate in only one direction independent of the...

Homework Statement I have Watts per second, is this the same as Joules? Homework Equations The Attempt at a Solution

Homework Statement Find the conservation of electrical energy in the LCR Homework Equations LdQ^2/dt + Q/C = 0 LdQ^2/dt + RdQ/dt + Q/C = 0 The Attempt at a Solution LdQ^2/dt + Q/C = RdQ/dt

hi , i have a dought ..electrical energy generated are directly go to the load by means of transmission from generating station to substation and then to load .. this process happens in live (that means energy is being generated always) or generated electrical energy get stored in sub-station or...

Hello. This question has kept me up all night: What mechanism would keep a wheel spinning using as little electrical energy as possible? Let's say we have a toy car (could be anything that involves a wheel) that is already in motion and moving with a constant velocity. What would you build...

Does electrical energy reside in kinetic energy of electrons?

What does a capacitor actually do? Does it store electrical energy or does is store charge? Please Explain.

An insulated 8-m^3 rigid tank contains air at 600 kPa and 400 K. A valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 200 kPa. The air temperature during the process is maintained constant by an electric resistance heater placed in the...

Homework Statement I don't understand voltage and electrical energy. So Voltage is power/unit of current. also V=RI. In power lines, the power losses are minimised by using large amounts of voltage. From P=VI, I gets smaller. But ohms law says current will increase. HUH? Power loss = RI^2...

Homework Statement Calculate the electrical energy (in Joules units) which is stored in a battery with nominal voltage, 9v, and with a charge capacity of 120 mAh. Homework Equations J (Electrical Energy) = V (Voltage) x Ah (battery capacity) The Attempt at a Solution J = V x Ah...

I have problem understanding why the surface integral disappear when taking the volume to very large in this equation: W_e = \frac 1 2 \int_{v'} \rho_v V dv' = \frac 1 2 \int_{v'} (\nabla \cdot \vec D)V dv' = \frac 1 2 \int_{s'} V \vec D \cdot \hat n ds' \;+\; \frac 1 2 \int_{v'} \vec E...

Calculate the work done by a 3.0V battery as it charges a 7.8-microFarad capacitor in the flash unit of a camera. The Attempt at a Solution I realize that Work = Energy. And by using U = .5CV^2 I can easily come up with the answer. But when I first started doing the problem, I tried doing it...

I'm in 10th grade. My science textbook basically explains all energy conversions in one 3-page paragraph; it is too simplified to understand what exactly is happening. The textbook is explaining how does a generater work. There is only one sentence: The turbines turn a coil of wire in a...

Homework Statement The total consumption of electrical energy in Country A is about 1.5 x 1015 Joules/year. What is the average rate of electrical energy consumption in Watts? So, my friend and I were arguing. He said, 1.5 x 1015 is the answer. I said, since watts is equal to Joules /...

I have a solenoid which has a current passing through it which increases linearly with time. I have proved that the energy stored in the magnetic field is equal to the energy being pumped in according to the surface integral of the poynting vector. This implies the energy stored in the electric...

Hello there, I'm new in this forum so sorry if this is not the right session to post my question. Well I'm taking a subject called Energy: Origins, Conversion and Uses (I guess this is the correct translation) and I need to do a final project which requires me to generate electrical...

Homework Statement Can you please give me some questions and I will see if I can work out the electrical energy? Homework Equations This is what I am going to be working from (Please tell me if it's not correct): Energy = Power x Time OR E=Pt Power = Current x Voltage OR P=IV...

Many texts I've come across use "electrical energy" and "electricity" interchangeably. Some online dictionaries also state "electricity" and "electrical energy" as synonyms. Are they really the same? In the topic called energy, my friend wrote "Electrical energy is the energy possessed by...

need ur help for this one hope sum1 replies

can we obtain electrical energy from sound signals?? hello everyone.. i want to know that is there ny method or any apparatus to convert the sound signals into electrical energy efficiently such that it will glow a led or can acticate a buzzer! well i know about sound detector circuits...

conversion of electromagnetic radiations to electrical energy! hello everyone! few days before i bought a glowing sticker which sticks near the antenna of my mobile and glow when any call comes to my mobile or when i make any call from my mobile! All i know about it is that it detects the...

hey guys! i want to start a new project in my college with my friends... we have thought of something like converting vibrational energy to electrical energy with the help of peizoelectric crystal! please can anybody point us to direction as where to start practically.. we have theoratical...

I am currently working on a project that requires me to design and analyse a solar powered. My motor has features such; 36v (Max), 300A (Max), 93% efficiency, 2.5mΩ, 12kW (Max). I used the maximum power and the efficiency to calculate the power input (from the battery). How do i calculate the...

Question: Using a Joule's calorimeter to investigate the efficiency of the conversion of electrical energy to heat energy. Equipment: Joule's calorimeter balance thermometer (0-100degrees celsius) power supply (0-12V) ammeter (0-5A) rheostat stopwatch electrical leads and distilled...

Hey, my friend started asking questions about how energy works with circuits, and he linked me this page. I have never heard of poynting fields before. The idea I find most interesting is where the "Electromagnetic energy flows out of the battery and into the empty space around the circuit"...

Hello everyone! I have an idea of making a device that can convert noise into electrical energy. In many fields (industries, cars, construction machines,...), some used machines make much noise, then I thought as sound (noise) causes mechanical energy, why not convert that mechanical into...

When work is done on a Coulomb of charge, it gains potential energy equal to the amount of work done on it. Now, since this charge is moving, it's electric field is changing. Because of that, a changing magnetic field surrounds a charge. Now, since this only happens when the Coulomb is moved by...

My specific question is "How is electrical energy made available to devices?" Everyone knows that "devices transfer electrical energy into useful forms" of energy, such as light and heat. What I have discovered is that no source I have found has been able to describe exactly how devices GET...

Homework Statement two electrons separated by a large distance are fired directly at each other. The closest approach in this head on collision is 4e-14 m. One electron starts with twice the speed of the other. Assuming there is no deflection from the original path, determine the initial...

What is the best and most practical way to transform particular mechanical energy into electrical energy.I am not quite familiar to physics so I' ll try to explain what I want outsider way. When I say"particular mechanical energy" I mean the energy consisting of many low power hits.One hit make...

Homework Statement Electrical Immersion heater unit Needs to heat 10,000 litres of water from 24 Degrees C to 30 Degrees C in 24 hours Heater is connected to 240 V. Specific heat of the water 4.19 kJ kg-1 °C-1 and the energy gained by water is calculated from the formula Q=mc(Delta)T...

A mass is winded via string aroung a flywheel and allowed to fall a specific height before detachement. The flywheel is connected to a small DC motor via gears and starts generating electricity once the mass is allowed to fall.. Now without the DC motor ( generator) the equation of energy...

Homework Statement A solar cell provides an emf of 0.70 V. If the cell supplies a constant current of 20.5 mA for 8.0 h, how much electrical energy does it supply? 413.3 J What is the power - the rate at which it supplies electrical energy? Homework Equations P=work/time units J/s i...

Hi all, Can Anyone tell me What is actually happening when we placed an Electrical rod in a Bucket Of Water? No Doubt after some time water will heat. But how? I mean to say How Electrical Energy Converted To Heat Energy?

ok all i can find on google is Heat to Electrical so i thought id ask here. how exactly do i explain how electrical energy is converted to heat energy? right now I have this: As the voltage travels through the coil wire, the wire gives off heat. it doesn't feel like enough. "the...

Homework Statement I have a motor with WK^2 = 4 lb-ft turning at 5400 RPM (3 * base speed) and I want to slow it to 1530 RPM (.85 * base speed). The motor is a 25HP 4 pole with a base speed of 1800 RPM. How much electrical energy must I absorb? Homework Equations The Attempt at a...

Here is my problem [the last one of a lot that I already got all right and have to turn in by midnight - so you can sense my frustration, lol.] A .39microF capacitor is charged by a 1.5 V battery. After being charged, the capacitor is connected to a small electric motor. a) Assuming 100%...

I always thought that an electrode is what transforms the mechanical energy of a generator into electrical energy. In a children's book about technology that I was reading yesterday, I saw something that has confused me. The book seemed to imply that the movement of a the wires of a coil...

Someone comes up with an idea to convert kinetic to electrical energy. Who should he contact? He needs to find an Engineer to calculate the amount of energy that could be produced / size of turbine / what kind of generator / size of generator, etc. based on the amount of energy displaced to...

A three phase and three wire energy meter has installed in a medium voltage network with a lot of third harmonic current and unbalanced load (approximately %10). As you know, any distortion in sine wave and deviation of rated frequency in AC electrical system may be cause the increasing of...

Okay, so the situation is a hydro-electric plant, assumed to have a vertical inlet pipe, of (s) metres high, and a opening to the turbine of (d) metres in diameter. The water is assumed to be stationary before it begins falling down the pipe (s) metres. So, I have the speed of the water when it...

Homework Statement A piece of copper wire is formed into a single circular loop of radius 10 cm. A magnetic field is oriented parallel to the normal to the loop, and it increases from 0 to 0.70 T in a time of 0.45 s. The wire has a resistance per unit length of 3.3 10-2 /m. What is the...