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===About Frequency===
: [[Frequency]] is [[measure]]d in [[Hertz]] ([[Hz]]).
{| class="wikitable"
|-
|[[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 oscillates [[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 '']