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{| 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 20kΩ [[Electrical Resistor|resistorwire]] has a [[Electrical Current|current]] resistance of 31mA15mΩ. Calculate the '''power''' dissipated by the [[wire]] when a [[Electrical Current|current]] of 3.5A is in the [[resistorwire]] correct to two [[Significant Figures|significant figures]].
|-
| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in [[SI Unit]]s.'''
| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in [[SI Unit]]s.'''
I = 31mA = 31x10<sup>-3</sup>A.5A
R = 20kΩ 15mΩ = 20x1015x10<sup>-3</sup>Ω
|-
| 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 = (31 \times 10^-3.5)^2 \times 20 15 \times 10^-3</math>
<math>P = 190.22W18375W</math>
<math>P \approx 19W0.18W</math>
|}
====Finding Power from Potential Difference and Resistance====
{| class="wikitable"
| style="height:20px; width:200px300px; text-align:center;" |A [[Potential Difference|potential difference]] of 6.8V is applied across a 98kΩ [[resistorElectrical 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:200px300px; text-align:center;" |QuestionA 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:200px300px; text-align:left;" |'''1. State the known quantitiesin [[SI Unit]]s.''' V = 6.8V R = 13Ω| style="height:20px; width:200px300px; text-align:left;" |'''1. State the known quantitiesin [[SI Unit]]s.''' V = 56V R = 20kΩ = 20x10<sup>3</sup>Ω
|-
| style="height:20px; width:200px300px; 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:200px300px; 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>
|}