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===About Frequency===
: [[Frequency]] is [[measure]]d in [[Hertz]] (Hz).{| class="wikitable"|-| style="height:20px; width:200px; text-align:center;" |'''Water Waves'''|-|[[File:WaveFrequency.gif|center]]|-| style="height:20px; width:200px; text-align:center;" |The [[frequency]] of this [[wave]] can be found by counting the number of times the red marker [[oscillate]]s every [[second]].|}: The higher the [[frequency]] the quicker the [[wave]] [[Oscillation|oscillates]].: In [[sound]] [[frequency]] is known as [[pitch]]. A high [[pitch]] is a high [[frequency]].: In [[light]] [[frequency]] affects the [[colour]] of the [[light]]. Red is a low [[frequency]] and violet is a high [[frequency]]. ===Equation===Frequency = 1/(Period) <math>f = \frac{1}{T}</math> Where: f = [[Frequency]] T = [[Period|time period]] (the [[time]] it takes for one [[wave]] to pass a point). ==Key Stage 4=====Meaning===[[Frequency]] is the number of [[wave]]s that pass a given point in one [[second]]. ===About Frequency===: [[Frequency]] is a [[scalar]] quantity because it has [[magnitude]] but no direction.: The [[SI Unit]] of [[frequency]] is [[Hertz]] (Hz). {| class="wikitable"|-| style="height:20px; width:200px; text-align:center;" |'''Water Waves'''|-|[[File:WaveFrequency.gif|center]]|-| style="height:20px; width:200px; text-align:center;" |The [[frequency]] of this [[wave]] can be found by counting the number of times the red marker [[oscillate]]s every [[second]].|}: The higher the [[frequency]] the quicker the [[wave]] [[Oscillation|oscillates]].: In [[sound]] [[frequency]] is known as [[pitch]]. A high [[pitch]] is a high [[frequency]].: In [[light]] [[frequency]] affects the [[colour]] of the [[light]]. Red is a low [[frequency]] and violet is a high [[frequency]].: When [[wave]] enters a new [[medium]] it will remain the same [[frequency]] but the [[Wave Speed|wave speed]] and [[wavelength]] will change.: [[Frequency]] can be found by counting the number of [[wave]]s which pass a point in a given [[time]] and dividing this by the [[time]]. ===Equation=======Equation 1====''NB: You do not need to remember this equation but you should know how to find [[frequency]] given the [[time]] taken for one [[wave]] to pass a point.'' Frequency = 1/(Period) <math>f = \frac{1}{T}</math> Where:f = [[Frequency]] T = [[Period|time period]] (the [[time]] it takes for a wave to pass a point). ====Equation 2====''NB:You do not need to remember this equation but you should know how to find [[frequency]] given the number of [[wave]]s passing a point and the [[time]] taken.'' Frequency = (Number of Waves which pass a point)/(Time taken for waves to pass a point) <math>f = \frac{n}{t}</math> Where:f = [[Frequency]] n = Number of [[wave]]s which pass a point. t = The [[time]] taken for those [[wave]]s to pass a point. ====Equation 3====''NB: You should remember this equation with v as the subject of the formula.'' Frequency = (Wave Speed)/(Wavelength) <math> f = \frac{v}{\lambda}</math> Where <math> \lambda</math> = The [[wavelength]] of the [[wave]]. <math>v</math> = The [[Wave Speed|wave speed]] of the [[wave]]. <math>f</math> = The [[frequency]] of the [[wave]]. ===Example Calculations=======Finding Frequency from Time Period===={| class="wikitable"| style="height:20px; width:300px; text-align:center;" |Calculate the [[frequency]] of a [[wave]] with a [[period]] of 0.04 seconds.| style="height:20px; width:300px; text-align:center;" |A giant pendulum takes 16 seconds to make one complete [[oscillation]]. Calculate the [[frequency]] of the pendulum.|-| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities''' T = 0.04s| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities''' T = 16s|-| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math> f = \frac{1}{T}</math> <math> f = \frac{1}{0.04}</math> <math> f = 25Hz</math>| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math> f = \frac{1}{T}</math> <math> f = \frac{1}{16}</math> <math> f = 0.0625Hz</math>|} ====Finding Frequency from the number of waves and time taken===={| class="wikitable"| style="height:20px; width:300px; text-align:center;" |A scientist wants to determine the [[frequency]] of a pendulum. They count that the pendulum [[oscillate]]s 15 times over 20 seconds. Calculate the [[frequency]] of the pendulum.| style="height:20px; width:300px; text-align:center;" |A sailor notices a buoy bounce up and down 24 times over a minute. Calculate the [[frequency]] of the [[wave]]s.|-| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities''' n = 15 t = 20s| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities''' n = 24 t = 60|-| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>f = \frac{n}{t}</math> <math>f = \frac{15}{20}</math> <math>f = 0.75Hz</math> | style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math>f = \frac{n}{t}</math> <math>f = \frac{24}{60}</math> <math>f = 0.4Hz</math>|} ====Finding Frequency from Wavelength and Wave Speed===={| class="wikitable"| style="height:20px; width:300px; text-align:center;" |A [[microwave]] travelling at a speed of 3.0x10<sup>8</sup>m/s has a [[wavelength]] of 0.051m. Calculate the [[frequency]] of the [[wave]] correct to two [[Significant Figures|significant figures]].| style="height:20px; width:300px; text-align:center;" |An [[ultrasound]] [[wave]] of [[wavelength]] 0.125m passes through an [[Iron]] block at a [[speed]] of 5000m/s. Calculate the [[frequency]] of the [[wave]] correct to two [[Significant Figures|significant figures]].|-| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities''' v = 3.0x10<sup>8</sup>m/s λ = 0.051m| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities''' v = 5000m/s λ = 0.125m|-| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math> f = \frac{v}{\lambda}</math> <math> f = \frac{3.0 \times 10^8}{0.051}</math> <math> f = 5882352941Hz</math> <math> f \approx 5900000000Hz</math> | style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math> f = \frac{v}{\lambda}</math> <math> f = \frac{5000}{0.125}</math> <math> f = 40000Hz</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 ''Frequency (f), pages 50-1, 583, GCSE Physics, Hodder, 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=f0dfb66dafcb0c6e9449e7b1a4ae1ac201 ''Frequency, page 73, GCSE Physics; The Revision Guide, CGP, 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 ''Frequency, pages 189, 190, GCSE Combined Science Trilogy; Physics, 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 ''Frequency, pages 190-3, 200-1, 206-9, 213-15, 218, 222, 224, 236-7, 275, GCSE Physics; Student Book, Collins, 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 ''Frequency, pages 226, 227, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1471851362/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851362&linkCode=as2&tag=nrjc-21&linkId=7d78d70a2044ee9982dae010c94af92a ''Frequency, pages 257, GCSE Combined Science Trilogy 2, 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 ''Frequency; human hearing range, page 280, GCSE Physics; The Complete 9-1 Course for AQA, 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=f0dfb66dafcb0c6e9449e7b1a4ae1ac202 ''Frequency; human hearing range, page 88, GCSE Physics; The Revision Guide, CGP, AQA '']:[https://www.amazon.co.uk/gp/product/1471851362/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851362&linkCode=as2&tag=nrjc-21&linkId=7d78d70a2044ee9982dae010c94af92a ''Frequency; Measurement of, pages 260, GCSE Combined Science Trilogy 2, 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 ''Frequency; of EM waves, pages 200, 203, 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 ''Frequency; of EM waves, pages 242, 245, GCSE Physics; The Complete 9-1 Course for AQA, 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=f0dfb66dafcb0c6e9449e7b1a4ae1ac203 ''Frequency; of EM waves, pages 76, 81, 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 ''Frequency; of mains electricity, page 66, 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=f0dfb66dafcb0c6e9449e7b1a4ae1ac204 ''Frequency; of mains supply, page 31, GCSE Physics; The Revision Guide, CGP, 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 ''Frequency; of mains supply, page 86, 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 ''Frequency; of mains supply, page 89, GCSE Physics; The Complete 9-1 Course for AQA, 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 ''Frequency; table, pages 40-1, GCSE Physics; Student Book, Collins, 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 ''Frequency (waves), page 91, 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 ''Frequency (waves); of hearing, page 104, 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 ''Frequency (waves); of infrasound, page 109, 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 ''Frequency (waves); of ultrasound, page 106, 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 ''Frequency, pages 164-166, 168, 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 ''Frequency, pages 32-34, 43, GCSE Physics; The Revision Guide, CGP, 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 ''Frequency, pages 331, 340, GCSE Combined Science, 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 ''Frequency, pages 49, 72, GCSE Physics, Pearson Edexcel ''] ===References===:[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 ''Frequency, pages 137, 142, 149, , 153, 179, 256-157, Gateway GCSE Physics, Oxford, 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 ''Frequency, pages 186-188, 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 ''Frequency, pages 59-61, 64, Gateway GCSE Physics; The Revision Guide, CGP, OCR '']