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===About Power===
: The [[unit]] of [[power]] is the [[Watt]].
: [[Power]] is how quickly [[energy]] is [[Energy Transfer|transferred]] from one [[Energy Store|store]] into another.
: [[Energy Transfer]]ed is the same as [[Work Done]], so [[power]] is also the rate of [[Work Done|work done]].
===Equation===
Where:
P = Power E = [[Energy Transfer]]red = W = [[Work Done]] t = Time ==Key Stage 4=====Meaning===[[Power]] is the rate of [[Energy Transfer]] or [[Work Done]]. ===About Power===: The [[SI Unit]] of [[power]] is the [[watt]].: [[Power]] is a [[scalar]] quantity as it has [[magnitude]] but does not have a direction. ===Equations=======Power, Work Done and Time===='' '''Power''' = ''<math>\frac{Work Done}{Time}</math> <math>P = \frac{W}{t}</math> Where: P = Power: E = [[Energy Transferred Transfer]]red = W = [[Work Done]] t = Time ====Power, Current and Potential Difference==== '' '''Power''' = ([[Electrical Current|Current]]) x ([[Potential Difference]]) <math>P = IV</math> Where: P = Power I = [[Electrical Current|Current]] V = [[Potential Difference]] ===Calculating Power from Work Done==={| class="wikitable"| style="height:20px; width:200px; text-align:center;" |A bow at full stretch [[Energy Transfer|transfers]] 50J of [[energy]] from its [[Elastic Potential Energy Store|elastic potential energy store]] into the [[Kinetic Energy Store|kinetic energy store]] of an arrow in 0.02 [[second]]s. Calculate the '''power''' of this transfer correct to two [[Significant Figures|significant figures]].| style="height:20px; width: 200px; text-align:center;" |A piano falls down a flight of stairs. In this fall 5.4kJ of [[energy]] is [[Energy Transfer|transferred]] from the [[Gravitational Potential Energy Store|gravitational potential energy store]] into the [[Kinetic Energy Store|kinetic energy store]] of the piano. It take 0.80 seconds to reach the bottom of the stairs. Calculate the average '''power''' of this transfer correct to two [[Significant Figures|significant figures]].| style="height:20px; width:200px; text-align:center;" |A '[[weight]] lifter' lifts a 2000N [[weight]] a distance of 1.2 [[metre]] from its original position. They do this in 0.70 [[second]]s. Calculate the [[power]] output of the '[[weight]] lifter' correct to two [[Significant Figures|significant figures]].|-| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' W = 50J t = Time0.02s| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' W = 5.4kJ = 5400J t = 0.80s| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' F = 2000N d = 1.2m t = 0.70s|-| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P = \frac{W}{t}</math> <math>P = \frac{50}{0.02}</math> <math>P = 2500W</math>| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P = \frac{W}{t}</math> <math>P = \frac{5400}{0.80}</math> <math>P = 6750W</math> <math>P \approx 6800W</math>| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>W = \vec F \vec d</math> <math>W = \vec F \times \vec d</math> <math>W = 2000 \times 1.2</math> <math>W = 2400J</math> <math>P = \frac{W}{t}</math> <math>P = \frac{2400}{0.7}</math> <math>P = 3428.57W</math> <math>P \approx 3400W</math> |} ===Calculating Electrical Power==={| class="wikitable"| style="height:20px; width:200px; text-align:center;" |An electrical fan is plugged into a [[Electrical Socket|socket]] supplying 230V. An [[ammeter]] reading shows that the [[Electrical Current|current]] going into the fan is 0.20amps. Calculate the power of the fan correct to two [[Significant Figures|significant figures]].| style="height:20px; width:200px; text-align:center;" |A light bulb is supplied a current of 625mA. The [[Potential Difference|potential difference]] across the terminals on the [[Electrical Bulb|light bulb]] is 96 [[volt]]s. Calculate the [[power]] of the [[Electrical Bulb|bulb]] correct to two [[Significant Figures|significant figures]].| style="height:20px; width:200px; text-align:center;" |A kettle is plugged into the [[Mains Electricity|mains supply]] which operates at 230V. It receives a current of 9.2Amps Calculate the power of the kettle correct to two [[Significant Figures|significant figures]].|-| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' I = 0.20A V = 230V| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' I = 625mA = 0.625A V = 96V| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' I = 9.2A V = 230V|-| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P = IV</math> <math>P = I \times V</math> <math>P = 0.20 \times 230</math> <math>P = 46W</math>| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P = IV</math> <math>P = I \times V</math> <math>P = 0.625 \times 96</math> <math>P = 60W</math>| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P = IV</math> <math>P = I \times V</math> <math>P = 9.2 \times 230</math> <math>P = 2116W</math> <math>P \approx 2100W</math>|} ===References=======AQA==== :[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Power, pages 10-11, GCSE Physics, Hodder, AQA '']:[https://www.amazon.co.uk/gp/product/0008158770/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158770&linkCode=as2&tag=nrjc-21&linkId=ec31595e720e1529e49876c3866fff6e ''Power, pages 13, 20-1, GCSE Physics; Student Book, Collins, AQA '']:[https://www.amazon.co.uk/gp/product/178294558X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=178294558X&linkCode=as2&tag=nrjc-21&linkId=f0dfb66dafcb0c6e9449e7b1a4ae1ac372 ''Power, pages 14, 17, GCSE Physics; The Revision Guide, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1782945598/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945598&linkCode=as2&tag=nrjc-21&linkId=ad276ad49df77ab4b40ab4fd0fe10187 ''Power, pages 172, 174, GCSE Combined Science; The Revision Guide, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/019835939X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=019835939X&linkCode=as2&tag=nrjc-21&linkId=57e96876985fc39b1a3d8a3e3dc238b6 ''Power, pages 20-21, 68-69, 72-73, 229, GCSE Physics; Third Edition, Oxford University Press, AQA '']:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Power, pages 266-7, GCSE Combined Science Trilogy 1, Hodder, AQA '']:[https://www.amazon.co.uk/gp/product/1782946403/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782946403&linkCode=as2&tag=nrjc-21&linkId=32a0abb60dff015b15b50e9b1d7b4644 ''Power, pages 32, 33, GCSE Combined Science Trilogy; Physics, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1782945970/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945970&linkCode=as2&tag=nrjc-21&linkId=a120d24dcc7cc7a58192069a3aafc1d2 ''Power, pages 33, 34, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1782945598/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945598&linkCode=as2&tag=nrjc-21&linkId=ad276ad49df77ab4b40ab4fd0fe10188 ''Power; electrical, pages 189, 190, GCSE Combined Science; The Revision Guide, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/178294558X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=178294558X&linkCode=as2&tag=nrjc-21&linkId=f0dfb66dafcb0c6e9449e7b1a4ae1ac373 ''Power; electrical, pages 32, 33, GCSE Physics; The Revision Guide, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/0008158770/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158770&linkCode=as2&tag=nrjc-21&linkId=ec31595e720e1529e49876c3866fff6e ''Power; electrical, pages 47, 70-3, 75, 77, GCSE Physics; Student Book, Collins, AQA '']:[https://www.amazon.co.uk/gp/product/1782946403/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782946403&linkCode=as2&tag=nrjc-21&linkId=32a0abb60dff015b15b50e9b1d7b4644 ''Power; electrical, pages 88-91, GCSE Combined Science Trilogy; Physics, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1782945970/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945970&linkCode=as2&tag=nrjc-21&linkId=a120d24dcc7cc7a58192069a3aafc1d2 ''Power; electrical, pages 91-94, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Power; in transformers, page 237, GCSE Physics, Hodder, AQA '']:[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Power; loss during electricity transmission, pages 238-9, GCSE Physics, Hodder, AQA '']:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Power; of electrical appliances, pages 307-8, GCSE Combined Science Trilogy 1, Hodder, AQA '']:[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Power; of electrical devices, pages 53-4, GCSE Physics, Hodder, AQA '']:[https://www.amazon.co.uk/gp/product/1782945970/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945970&linkCode=as2&tag=nrjc-21&linkId=a120d24dcc7cc7a58192069a3aafc1d2 ''Power; of transformers, pages 311, 312, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1782945598/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945598&linkCode=as2&tag=nrjc-21&linkId=ad276ad49df77ab4b40ab4fd0fe10189 ''Power; ratings, page 189, GCSE Combined Science; The Revision Guide, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/0008158762/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158762&linkCode=as2&tag=nrjc-21&linkId=a0fffa35b3ea49a63404f6704e0df7cc ''Powers of ten (maths), GCSE Chemistry; Student Book, Collins, AQA '']:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Powers of ten, page 316, GCSE Combined Science Trilogy 1, Hodder, AQA '']:[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Powers of ten, page 64, GCSE Physics, Hodder, AQA ''] ====Edexcel==== :[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Power, pages 203, 204, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1292120223/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120223&linkCode=as2&tag=nrjc-21&linkId=068ecf40278c32406a7f1c6e66751417 ''Power, pages 80, 131, 154-155, 178, GCSE Physics, Pearson Edexcel '']:[https://www.amazon.co.uk/gp/product/1292120223/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120223&linkCode=as2&tag=nrjc-21&linkId=068ecf40278c32406a7f1c6e66751417 ''Power; electrical, page 155, GCSE Physics, Pearson Edexcel '']:[https://www.amazon.co.uk/gp/product/1782945741/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945741&linkCode=as2&tag=nrjc-21&linkId=30da4f2178da182547b62a7329d13b57 ''Power; electrical, page 191, GCSE Combined Science; The Revision Guide, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782945733/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945733&linkCode=as2&tag=nrjc-21&linkId=2a2dbec9db6bf5766c0458d908fa0a52 ''Power; electrical, page 78, GCSE Physics; The Revision Guide, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Power; electrical, pages 244, 245, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782945733/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945733&linkCode=as2&tag=nrjc-21&linkId=2a2dbec9db6bf5766c0458d908fa0a52 ''Power; lenses, page 41, GCSE Physics; The Revision Guide, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Power; of a lens, page 121, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Power; ratings, page 244, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782945741/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945741&linkCode=as2&tag=nrjc-21&linkId=30da4f2178da182547b62a7329d13b57 ''Power; work done, page 180, GCSE Combined Science; The Revision Guide, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782945733/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945733&linkCode=as2&tag=nrjc-21&linkId=2a2dbec9db6bf5766c0458d908fa0a52 ''Power; work done, page 66, GCSE Physics; The Revision Guide, CGP, Edexcel ''] ====OCR====:[https://www.amazon.co.uk/gp/product/1782945695/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945695&linkCode=as2&tag=nrjc-21&linkId=ceafcc80bcad6b6754ee97a0c7ceea53 ''Power, pages 169, 182, 207, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR '']:[https://www.amazon.co.uk/gp/product/1782945687/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945687&linkCode=as2&tag=nrjc-21&linkId=9a598e52189317a20311d7a632747bc9 ''Power, pages 35, 50, 87, Gateway GCSE Physics; The Revision Guide, CGP, OCR '']:[https://www.amazon.co.uk/gp/product/0198359837/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359837&linkCode=as2&tag=nrjc-21&linkId=3c4229e8b023b2b60768e7ea2307cc6f ''Power; And efficiency, pages 202-211, Gateway GCSE Physics, Oxford, OCR '']:[https://www.amazon.co.uk/gp/product/0198359837/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359837&linkCode=as2&tag=nrjc-21&linkId=3c4229e8b023b2b60768e7ea2307cc6f ''Power; Calculations, pages 75, Gateway GCSE Physics, Oxford, OCR '']:[https://www.amazon.co.uk/gp/product/0198359837/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359837&linkCode=as2&tag=nrjc-21&linkId=3c4229e8b023b2b60768e7ea2307cc6f ''Power; Electrical appliances, pages 202, Gateway GCSE Physics, Oxford, OCR '']:[https://www.amazon.co.uk/gp/product/0198359837/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359837&linkCode=as2&tag=nrjc-21&linkId=3c4229e8b023b2b60768e7ea2307cc6f ''Power; Electrical power, pages 114-115, Gateway GCSE Physics, Oxford, OCR '']