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Examples of power

Examples of power are limited only by the imagination, because there are as many types as there are forms of work and energy. (See [link] for some examples.) Sunlight reaching Earth’s surface carries a maximum power of about 1.3 kilowatts per square meter ( kW/m 2 ) . size 12{ \( "kW/m" rSup { size 8{2} } \) "." } {} A tiny fraction of this is retained by Earth over the long term. Our consumption rate of fossil fuels is far greater than the rate at which they are stored, so it is inevitable that they will be depleted. Power implies that energy is transferred, perhaps changing form. It is never possible to change one form completely into another without losing some of it as thermal energy. For example, a 60-W incandescent bulb converts only 5 W of electrical power to light, with 55 W dissipating into thermal energy. Furthermore, the typical electric power plant converts only 35 to 40% of its fuel into electricity. The remainder becomes a huge amount of thermal energy that must be dispersed as heat transfer, as rapidly as it is created. A coal-fired power plant may produce 1000 megawatts; 1 megawatt (MW) is 10 6 W size 12{"10" rSup { size 8{6} } " W"} {} of electric power. But the power plant consumes chemical energy at a rate of about 2500 MW, creating heat transfer to the surroundings at a rate of 1500 MW. (See [link] .)

A distant view of a coal-fired power plant with clearly visible cooling towers generating electric power and emitting a large amount of gases.
Tremendous amounts of electric power are generated by coal-fired power plants such as this one in China, but an even larger amount of power goes into heat transfer to the surroundings. The large cooling towers here are needed to transfer heat as rapidly as it is produced. The transfer of heat is not unique to coal plants but is an unavoidable consequence of generating electric power from any fuel—nuclear, coal, oil, natural gas, or the like. (credit: Kleinolive, Wikimedia Commons)
Power output or consumption
Object or Phenomenon Power in Watts
Supernova (at peak) 5 × 10 37 size 12{5 times "10" rSup { size 8{"37"} } } {}
Milky Way galaxy 10 37 size 12{"10" rSup { size 8{"37"} } } {}
Crab Nebula pulsar 10 28 size 12{"10" rSup { size 8{"28"} } } {}
The Sun 4 × 10 26 size 12{4 times "10" rSup { size 8{"26"} } } {}
Volcanic eruption (maximum) 4 × 10 15 size 12{4 times "10" rSup { size 8{"15"} } } {}
Lightning bolt 2 × 10 12 size 12{2 times "10" rSup { size 8{"12"} } } {}
Nuclear power plant (total electric and heat transfer) 3 × 10 9 size 12{3 times "10" rSup { size 8{9} } } {}
Aircraft carrier (total useful and heat transfer) 10 8 size 12{"10" rSup { size 8{8} } } {}
Dragster (total useful and heat transfer) 2 × 10 6 size 12{2 times "10" rSup { size 8{6} } } {}
Car (total useful and heat transfer) 8 × 10 4 size 12{8 times "10" rSup { size 8{4} } } {}
Football player (total useful and heat transfer) 5 × 10 3 size 12{5 times "10" rSup { size 8{3} } } {}
Clothes dryer 4 × 10 3 size 12{4 times "10" rSup { size 8{3} } } {}
Person at rest (all heat transfer) 100 size 12{"100"} {}
Typical incandescent light bulb (total useful and heat transfer) 60 size 12{"60"} {}
Heart, person at rest (total useful and heat transfer) 8 size 12{8} {}
Electric clock 3 size 12{3} {}
Pocket calculator 10 3 size 12{"10" rSup { size 8{-3} } } {}

Power and energy consumption

We usually have to pay for the energy we use. It is interesting and easy to estimate the cost of energy for an electrical appliance if its power consumption rate and time used are known. The higher the power consumption rate and the longer the appliance is used, the greater the cost of that appliance. The power consumption rate is P = W / t = E / t size 12{P= {W} slash {t} = {E} slash {t} } {} , where E size 12{E} {} is the energy supplied by the electricity company. So the energy consumed over a time t size 12{t} {} is

E = Pt. size 12{E= ital "Pt"} {}

Electricity bills state the energy used in units of kilowatt-hours ( kW h ) , size 12{ \( "kW" cdot h \) ,} {} which is the product of power in kilowatts and time in hours. This unit is convenient because electrical power consumption at the kilowatt level for hours at a time is typical.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Unit 5 - work and energy. OpenStax CNX. Jan 02, 2016 Download for free at https://legacy.cnx.org/content/col11946/1.1
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