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'''Electrical power''' is the rate of [[Electrical Energy Transfer|electrical energy transfer]] in an a [[Electrical Component|component]].

:The [[SI Unit]]s of '''electrical power''' are [[Watt]]s.: '''Electrical power''' is the [[Work Done|work done]] by an [[Electrical Current|electrical current]] per unit [[time]]. ===Equations=======Power, Work Done and Time====''NB: You must remember this equation.'' '''Power''' = (Electrical Work Done)/(time) <math>P=\frac{W}{t}</math> Where <math>P</math> = '''Electrical Power'''. <math>W</math> = [[Electrical Energy Transfer]]red or [[Work Done]] by an [[Electrical Current|electrical current]]. <math>t</math> = The [[time]] over which [[energy]] is [[Energy Transfer|transferred]]. ====Power, Current and Potential Difference====''NB: You must remember this equation.'' '''Power''' = (Current) x (Potential Difference) <math>P=IV</math> Where <math>P</math> = '''Electrical Power'''. <math>I</math> = [[Electrical Current]] through a [[Electrical Component|component]]. <math>V</math> = [[Potential Difference]] across the [[Electrical Component|component]]. ====Power, Current and Resistance====''NB: You must remember this equation.'' '''Power''' = (Current)² x (Resistance) <math>P=I^2R</math> Where <math>P</math> = '''Electrical Power'''. <math>I</math> = [[Electrical Current]] through a [[Electrical Component|component]]. <math>R</math> = The [[Electrical Resistance|resistance]] of the [[Electrical Component|component]]. ====Power Potential Difference and Resistance====''NB: You must remember this equation.'' '''Power''' = (Current) x (Potential Difference) <math>P=\frac{V^2}{R}</math> Where <math>P</math> = '''Electrical Power'''. <math>V</math> = [[Potential Difference]] across the [[Electrical Component|component]]. <math>R</math> = The [[Electrical Resistance|resistance]] of the [[Electrical Component|component]]. ===Example Calculations=======Finding Power from Work Done and Time===={| class="wikitable"| style="height:20px; width:300px; text-align:center;" |An [[LED]] uses 842J over a period of 120 seconds. Calculate the '''power''' of the [[LED]] correct to two [[Significant Figures|significant figures]].| style="height:20px; width:300px; text-align:center;" |A toaster uses 180kJ while toasting some bread for 1 [[minute]] and 27 [[second]]s. Calculate the '''power''' of the toaster correct to 2 [[Significant Figures|significant figures]].|-| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities''' W = 842J t = 120s| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities''' W = 180kJ = 180x10³J t = 1min27s = 87s|-| style="height:20px; width:300px; 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{842}{120}</math> <math>P=7.01616W</math> <math>P\approx 7.0W</math>| style="height:20px; width:300px; 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{180 \times 10^3}{87}</math> <math>P=2068.9655W</math> <math>P\approx 2100W</math>|} ====Finding Power from Potential Difference and Current===={| class="wikitable"| style="height:20px; width:300px; 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:300px; 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:300px; text-align:left;" |'''1. State the known quantities in [[SI Unit]]s''' I = 625mA = 0.625A V = 96V| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in [[SI Unit]]s''' I = 9.2A V = 230V|-| style="height:20px; width:300px; 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:300px; 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>|} ====Finding Power from Current and Resistance===={| class="wikitable"| style="height:20px; width:300px; text-align:center;" |A [[Electrical Bulb|bulb]] uses a [[Electrical Current|current]] of 1.4A and has a [[Electrical Resistance|resistance]] of 9.1Ω. Calculate the '''power''' of the [[Electrical Bulb|bulb]] correct to two [[Significant Figures|significant figures]].| style="height:20px; width:300px; text-align:center;" |A [[wire]] has a resistance of 15mΩ. Calculate the '''power''' dissipated by the [[wire]] when a [[Electrical Current|current]] of 3.5A is in the [[wire]] correct to two [[Significant Figures|significant figures]].|-| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in [[SI Unit]]s.''' I = 1.4A R = 9.1Ω| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in [[SI Unit]]s.''' I = 3.5A R = 15mΩ = 15x10^-3Ω|-| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P = I^2R</math> <math>P = 1.4^2 \times 9.1</math> <math>P = 17.836W</math> <math>P \approx 18W</math>| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P = I^2R</math> <math>P = (3.5)^2 \times 15 \times 10^-3</math> <math>P = 0.18375W</math> <math>P \approx 0.18W</math>|} ====Finding Power from Potential Difference and Resistance===={| class="wikitable"| style="height:20px; width:300px; text-align:center;" |A [[Potential Difference|potential difference]] of 6.8V is applied across a [[Electrical Bulb|bulb]] with a [[Electrical Resistance|resistance]] of 13Ω. Calculate the '''power''' of the [[Electrical Bulb]] correct to two [[Significant Figures|significant figures]]. | style="height:20px; width:300px; text-align:center;" |A 20kΩ [[Electrical Resistor|resistor]] has a [[Potential Difference|potential difference]] of 56V. Calculate the '''power''' dissipated by the [[resistor]] correct to two [[Significant Figures|significant figures]].|-| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in [[SI Unit]]s.''' V = 6.8V R = 13Ω| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in [[SI Unit]]s.''' V = 56V R = 20kΩ = 20x10³Ω|-| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P=\frac{V^2}{R}</math> <math>P=\frac{6.8^2}{13}</math> <math>P=3.5569W</math> <math>P\approx 3.6W</math> | style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>P=\frac{V^2}{R}</math> <math>P=\frac{56^2}{20 \times 10^3}</math> <math>P=0.1568W</math> <math>P\approx0.16W</math> |} ===References=======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 ''Electrical power, pages 155, 174, GCSE Physics, Pearson Edexcel '']:[https://www.amazon.co.uk/gp/product/1292120193/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120193&linkCode=as2&tag=nrjc-21&linkId=572df39392fb4200db8391d98ae6314e ''Electrical power, pages 395, 408, GCSE Combined Science, Pearson Edexcel ''] ====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 ''Electrical power, pages 114-115, Gateway GCSE Physics, Oxford, OCR '']