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Difference between revisions of "Electrical Charge"

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==Key Stage 3==
 
==Key Stage 3==
 
===Meaning===
 
===Meaning===
−
'''Charge''' is a [[property]] of [[matter]] that can cause an [[Electrostatic Force]] between two [[object]]s.
+
'''Charge''' is a [[property]] of [[matter]] that can cause an [[Electrostatic Force|electrostatic force]] between two [[object]]s.
  
 
===About Charge===
 
===About Charge===
−
: There are two types of '''charge'''; [[Positive Charge|Positive]] and [[Negative Charge|Negative]].
+
: There are two types of '''charge'''; [[Positive Charge|positive]] and [[Negative Charge|negative]].
 
: Like '''charges''' [[repel]] each other and opposite '''charges''' [[attract]] each other.
 
: Like '''charges''' [[repel]] each other and opposite '''charges''' [[attract]] each other.
 +
: '''Charges''' create an [[Electrostatic Field|electrostatic field]] which affects other '''charged''' [[object]]s.
 +
 +
To see the [[Electrostatic Field|electrostatic field]] created by a '''charge''' click on the picture below to play a PHET simulation.
 +
{| class="wikitable"
 +
|[[File:PhetCharges.png|centre|300px|link=https://phet.colorado.edu/sims/html/charges-and-fields/latest/charges-and-fields_en.html]]
 +
|}
 +
 +
==Key Stage 4==
 +
===Meaning===
 +
'''Charge''' is a [[property]] of [[matter]] that can cause an [[Electrostatic Force|electrostatic force]] between two [[object]]s.
 +
 +
===About Charge===
 +
: The [[SI Unit]] of '''charge''' is the [[Coulomb]] (C).
 +
: '''Charge''' is a [[scalar]] quantity as it has [[magnitude]] but does not have a direction.
 +
: There are two types of '''charge'''; [[Positive Charge|positive]] and [[Negative Charge|negative]].
 +
: Like '''charges''' [[repel]] each other and opposite '''charges''' [[attract]] each other.
 +
: '''Charges''' create an [[Electrostatic Field|electrostatic field]] which affects other '''charged''' [[object]]s.
 +
: '''Charge''' is a conserved quantity which means; "'''Charge''' cannot be created or destroyed, it can only be transferred from one place to another."
 +
: A flow of '''charge''' is an [[Electrical Current|electrical current]].
 +
 +
===Equation===
 +
====Equation linking Charge, Current and Time====
 +
''NB: You should remember this equation with charge as the subject of the formula.''
 +
 +
'''Charge''' = (Current) x (time)
 +
 +
<math>Q=It</math>
 +
 +
Where
 +
 +
<math>Q</math> = The amount of [[Electrical Charge|charge]] flowing past a point.
 +
 +
<math>I</math> = The '''electrical current'''
 +
 +
<math>t</math> = The [[time]] taken for the [[Electrical Charge|charge]] to flow.
 +
 +
====Equation linking Charge, Potential Difference and Energy Transferred====
 +
''NB: You should remember this equation with energy transferred as the subject of the formula.''
 +
 +
'''Charge''' = (Energy Transferred)/(Potential Difference)
 +
 +
<math>Q=\frac{E}{V}</math>
 +
 +
Where
 +
 +
<math>Q</math> = The amount of [[Electrical Charge|charge]] that moves between two points.
 +
 +
<math>E</math> = The [[Energy Transfer]]red by the '''charge'''.
 +
 +
<math>V</math> = The [[Potential Difference|potential difference]] between two points.
 +
 +
===Example Calculations===
 +
====Finding Current from Charge and Time====
 +
{| class="wikitable"
 +
| style="height:20px; width:300px; text-align:center;" |A charge of 15 Coulombs passes through a point in a circuit ever 0.52 seconds. Calculate the current flowing past this point correct to two [[Significant Figures|significant figures]].
 +
| style="height:20px; width:300px; text-align:center;" |A capacitor stores a charge of 10C. It discharges in 12ms. Calculate the average current flowing out of the capacitor correct to two [[Significant Figures|significant figures]].
 +
|-
 +
| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
Q = 15C
 +
 +
t = 0.52s
 +
| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
Q = 10C
 +
 +
t = 12ms = 12x10<sup>-3</sup>s
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
 +
 +
<math>Q=It</math>
 +
 +
<math>15=I \times 0.52</math>
 +
| style="height:20px; width: 300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
 +
 +
<math>Q=It</math>
 +
 +
<math>10=I \times 12 \times 10^{-3}</math>
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
 +
 +
<math>I=\frac{15}{0.52}</math>
 +
 +
<math>I=28.846153A</math>
 +
 +
<math>I\approx29A</math>
 +
| style="height:20px; width: 300px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
 +
 +
<math>I=\frac{10}{12 \times 10^{-3}}</math>
 +
 +
<math>I=833.3A</math>
 +
 +
<math>I\approx830A</math>
 +
|}
 +
 +
====Finding Charge from Current and Time====
 +
{| class="wikitable"
 +
| style="height:20px; width: 300px; text-align:center;" |A battery supplies 4.7Amps to a bulb over a period of 14 seconds. Calculate the charge leaving the battery in this time correct to two [[Significant Figures|significant figures]].
 +
| style="height:20px; width: 300px; text-align:center;" |A hairdryer uses a current of 7.2A for 5 minutes to dry a person’s hair. Calculate the charge flowing through the hairdryer in this time correct to two [[Significant Figures|significant figures]].
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
I = 4.7A
 +
 +
t = 14s
 +
| style="height:20px; width: 300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
I = 7.2A
 +
 +
t = 5min = 300s
 +
|-
 +
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
 +
 +
<math>Q=It</math>
 +
 +
<math>Q=4.7 \times 14</math>
 +
 +
<math>Q = 65.8C</math>
 +
 +
<math>Q \approx 66C</math>
 +
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
 +
 +
<math>Q=It</math>
 +
 +
<math>Q=7.2 \times 300</math>
 +
 +
<math>Q = 2160C</math>
 +
 +
<math>Q \approx 2200C</math>
 +
|}
 +
 +
====Finding Time from Current and Charge====
 +
{| class="wikitable"
 +
| style="height:20px; width: 300px; text-align:center;" |A battery charger uses a current of 150mA to deliver a charge of 245 Coloumbs to a battery. Calculate the time taken to charge this battery correct to two [[Significant Figures|significant figures]].
 +
| style="height:20px; width: 300px; text-align:center;" |A cloud in a thunderstorm loses 15C in one lightening strike. At a current of 31,000kA. Calculate how long this lightning strike lasts correct to two [[Significant Figures|significant figures]].
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
I = 150mA = 150x10<sup>-3</sup>A
 +
 +
Q = 245C
 +
| style="height:20px; width: 300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
I = 31,000kA = 3.1x10<sup>7</sup>A
 +
 +
Q = 15C
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
 +
 +
<math>Q=It</math>
 +
 +
<math>245 = 150 \times 10^{-3} \times t</math>
 +
 +
| style="height:20px; width: 300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
 +
 +
<math>Q=It</math>
 +
 +
<math>15= 3.1 \times 10^7 \times t</math>
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
 +
 +
<math>t=\frac{245}{150 \times 10^{-3}}</math>
 +
 +
<math>t=1633.3s</math>
 +
 +
<math>t\approx1633.3s</math>
 +
| style="height:20px; width: 300px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
 +
 +
<math>t=\frac{15}{3.1 \times 10^7}</math>
 +
 +
<math>t = 4.8387 \times 10^{-7}s</math>
 +
 +
<math>t\approx4.8 \times 10^{-7}s</math>
 +
|}
 +
 +
====Finding Charge from Potential Difference and Energy Transferred====
 +
{| class="wikitable"
 +
| style="height:20px; width:300px; text-align:center;" |The [[Potential Difference|potential difference]] of 12V is placed across a [[Electrical Resistor|resistor]] increasing its [[Thermal Energy Store|thermal energy store]] by 3.7J as a result. Calculate the '''charge''' that has flowed through the [[Electrical Resistor|resistor]] in this time correct to two [[Significant Figures|significant figures]].
 +
| style="height:20px; width:300px; text-align:center;" |A [[circuit]] transfers 2.8kJ of [[energy]] [[electrically]] to a [[motor]]. The [[Potential Difference|potential difference]] across the [[motor]] is 1.5V. Calculate the'''charge''' that has flowed through the [[motor]] in this time correct to two [[Significant Figures|significant figures]].
 +
|-
 +
| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
V = 12V
 +
 +
E = 3.7J
 +
| style="height:20px; width:300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
V = 1.5V
 +
 +
E = 2.8kJ = 2.8x10<sup>3</sup>J
 +
|-
 +
| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
 +
 +
<math>Q=\frac{E}{V}</math>
 +
 +
<math>Q=\frac{3.7}{12}</math>
 +
 +
<math>Q=0.3083C</math>
 +
 +
<math>Q\approx0.31C</math>
 +
| style="height:20px; width:300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
 +
 +
<math>Q=\frac{E}{V}</math>
 +
 +
<math>Q=\frac{2.8 \times 10^3}{1.5}</math>
 +
 +
<math>Q=1866.7C</math>
 +
 +
<math>Q\approx1900C</math>
 +
|}
 +
 +
====Finding Potential Difference from Charge and Energy Transferred====
 +
{| class="wikitable"
 +
| style="height:20px; width: 300px; text-align:center;" |A '''charge''' of 84C transfers an [[energy]] of 20kJ. Calculate the [[Potential Difference|potential difference]] correct to two [[Significant Figures|significant figures]].
 +
| style="height:20px; width: 300px; text-align:center;" |170J of [[energy]] is transferred by a '''charge''' of 92mC. Calculate the [[Potential Difference|potential difference]] correct to two [[Significant Figures|significant figures]].
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
Q = 84C
 +
 +
E = 20kJ = 20x10<sup>3</sup>J
 +
| style="height:20px; width: 300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
Q = 92mC = 92x10<sup>-3</sup>C
 +
 +
E = 170J
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
 +
 +
<math>Q=\frac{E}{V}</math>
 +
 +
<math>84=\frac{20 \times 10^3}{V}</math>
 +
 +
| style="height:20px; width: 300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
 +
 +
<math>Q=\frac{E}{V}</math>
 +
 +
<math>92 \times 10^{-3}=\frac{170}{V}</math>
 +
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
 +
 +
<math>V=\frac{20 \times 10^3}{84}</math>
 +
 +
<math>V=238.0952V</math>
 +
 +
<math>V\approx 240V</math>
 +
 +
| style="height:20px; width: 300px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
 +
 +
<math>V=\frac{170}{92 \times 10^{-3}}</math>
 +
 +
<math>V=1847.826V</math>
 +
 +
<math>V\approx 1800V</math>
 +
|}
 +
 +
====Finding Energy Transferred from Charge and Potential Difference====
 +
{| class="wikitable"
 +
| style="height:20px; width: 300px; text-align:center;" |A bolt of lightning with a [[Potential Difference|potential difference]] 31,000kV transfers a '''charge''' of 15C. Calculate the [[Energy Transfer|energy transferred]] by this bolt of [[lightning]] correct to two [[Significant Figures|significant figures]].
 +
| style="height:20px; width: 300px; text-align:center;" |A 9V [[Electrical Battery|battery]] is able to mobilise a '''charge''' of 4.3kC during its operation. Calculate the total amount of [[energy]] stored in this [[Electrical Battery|battery]] correct to two [[Significant Figures|significant figures]].
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
V = 31,000kV = 3.1x10<sup>7</sup>V
 +
 +
Q = 15C
 +
| style="height:20px; width: 300px; text-align:left;" |'''1. State the known quantities in correct [[unit]]s.'''
 +
 +
V = 9V
 +
 +
Q = 4.3kC = 4.3x10<sup>3</sup>
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
 +
 +
<math>Q=\frac{E}{V}</math>
 +
 +
<math>15=\frac{E}{3.1 \times 10^7}</math>
 +
 +
| style="height:20px; width: 300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
 +
 +
<math>Q=\frac{E}{V}</math>
 +
 +
<math>4.3 \times 10^3 =\frac{E}{9}</math>
 +
|-
 +
| style="height:20px; width: 300px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
 +
 +
<math>E = 15 \times 3.1 \times 10^7</math>
 +
 +
<math>E = 4.65\times10^8 J</math>
 +
 +
<math>E\approx4.7\times10^8 J</math>
 +
 +
| style="height:20px; width: 300px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
 +
 +
<math>E = 4.3 \times 10^3 \times 9</math>
 +
 +
<math>E = 38700J</math>
 +
 +
<math>E \approx 39000 \times 10^4J</math>
 +
|}
 +
 +
===References===
 +
====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 ''Charge (electrical), pages 46-52, 71, 74-5, 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=f0dfb66dafcb0c6e9449e7b1a4ae1ac43 ''Charge; electric, page 24, 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=ad276ad49df77ab4b40ab4fd0fe09760 ''Charge; electric, pages 180, 189, 190, GCSE Combined Science; 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 ''Charge; electric, pages 61, 88-90, 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 ''Charge; electric, pages 63, 91-93, 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=f0dfb66dafcb0c6e9449e7b1a4ae1ac111 ''Electric charge, page 24, 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=ad276ad49df77ab4b40ab4fd0fe09875 ''Electric charge, pages 180, 189, 190, GCSE Combined Science; 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 ''Electric charge, pages 61, 88-90, 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 ''Electric charge, pages 63, 91-93, GCSE Physics; The Complete 9-1 Course for AQA, 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 ''Electric charge; ions, page 112, 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 ''Electric charge; ions, page 124, GCSE Physics; The Complete 9-1 Course for AQA, 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 ''Electric charge; of an atom, page 111, 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 ''Electric charge; of an atom, page 123, GCSE Physics; The Complete 9-1 Course for AQA, 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 ''Electric charge; relative charge, page 111, 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 ''Electric charge; relative charge, page 123, GCSE Physics; The Complete 9-1 Course for AQA, 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 ''Electric charge; static, pages 99, 103, GCSE Physics; The Complete 9-1 Course for AQA, CGP, 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 ''Charge (electric), page 221, 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 ''Charge, electrical, pages 144, 160-161, 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 ''Charge, electrical; energy, page 145, 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 ''Charge, electrical; point charges, page 164, GCSE Physics, 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 ''Electric charge, pages 94-97, 101, Gateway GCSE Physics, Oxford, OCR '']
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==Key Stage 5==
 +
===Meaning===
 +
'''Electrical charge''' is a [[Conservation of Charge|conserved]] quantity and a [[property]] of [[Subatomic Particle|particle]]s which allow them to interact via the [[Electromagnetic Interaction|electromagnetic interaction]].
 +
 +
===About Electrical Charge===
 +
: The [[SI Unit]] of '''charge''' is the [[Coulomb]] (C).
 +
: '''Charge''' is a [[scalar]] quantity as it has [[magnitude]] but does not have a direction.
 +
: '''Charges''' create an [[Electrostatic Field|electrostatic field]] which affects other '''charged''' [[object]]s.
 +
: '''Charge''' is a conserved quantity which means; "'''Charge''' cannot be created or destroyed, it can only be transferred from one place to another."
 +
: A flow of '''charge''' is an [[Electrical Current|electrical current]].
 +
 +
===About Electrical Charge at the Particle Level===
 +
: '''Charged''' [[Subatomic Particle|particles]] may exchange virtual [[photon]]s causing a change in their [[momentum]]. This results in the [[force]] of [[attract]]ion or [[repel|repulsion]] between '''charged''' [[Subatomic Particle|particles]].
 +
: As a [[Conservation of Charge|conserved quantity]] '''charge''' cannot be created or destroyed, but it can be transferred from one [[Subatomic Particle|particle]] to another. This occurs in the [[Weak Nuclear Interaction|weak interaction]] via the [[W-boson]].
 +
: The [[Electrical Charge|electrical charge]] passed between [[Subatomic Particle|subatomic particles]] during the [[Weak Nuclear Interaction|weak interaction]] has a [[magnitude]] of 1.60x10<sup>-19</sup> [[Coulomb]]s (the [[Elementary Charge|elementary charge]]).
 +
: The [[Electrical Charge|electrical charge]] of the [[proton]] is +1.60x10<sup>-19</sup> [[Coulomb]]s and the [[Electrical Charge|electrical charge]] of the [[electron]] is -1.60x10<sup>-19</sup> [[Coulomb]]s.

Latest revision as of 01:46, 5 December 2019

Key Stage 3

Meaning

Charge is a property of matter that can cause an electrostatic force between two objects.

About Charge

There are two types of charge; positive and negative.
Like charges repel each other and opposite charges attract each other.
Charges create an electrostatic field which affects other charged objects.

To see the electrostatic field created by a charge click on the picture below to play a PHET simulation.

PhetCharges.png

Key Stage 4

Meaning

Charge is a property of matter that can cause an electrostatic force between two objects.

About Charge

The SI Unit of charge is the Coulomb (C).
Charge is a scalar quantity as it has magnitude but does not have a direction.
There are two types of charge; positive and negative.
Like charges repel each other and opposite charges attract each other.
Charges create an electrostatic field which affects other charged objects.
Charge is a conserved quantity which means; "Charge cannot be created or destroyed, it can only be transferred from one place to another."
A flow of charge is an electrical current.

Equation

Equation linking Charge, Current and Time

NB: You should remember this equation with charge as the subject of the formula.

Charge = (Current) x (time)

\(Q=It\)

Where

\(Q\) = The amount of charge flowing past a point.

\(I\) = The electrical current

\(t\) = The time taken for the charge to flow.

Equation linking Charge, Potential Difference and Energy Transferred

NB: You should remember this equation with energy transferred as the subject of the formula.

Charge = (Energy Transferred)/(Potential Difference)

\(Q=\frac{E}{V}\)

Where

\(Q\) = The amount of charge that moves between two points.

\(E\) = The Energy Transferred by the charge.

\(V\) = The potential difference between two points.

Example Calculations

Finding Current from Charge and Time

A charge of 15 Coulombs passes through a point in a circuit ever 0.52 seconds. Calculate the current flowing past this point correct to two significant figures. A capacitor stores a charge of 10C. It discharges in 12ms. Calculate the average current flowing out of the capacitor correct to two significant figures.
1. State the known quantities in correct units.

Q = 15C

t = 0.52s

1. State the known quantities in correct units.

Q = 10C

t = 12ms = 12x10-3s

2. Substitute the numbers and evaluate.

\(Q=It\)

\(15=I \times 0.52\)

2. Substitute the numbers and evaluate.

\(Q=It\)

\(10=I \times 12 \times 10^{-3}\)

3. Rearrange the equation and solve.

\(I=\frac{15}{0.52}\)

\(I=28.846153A\)

\(I\approx29A\)

3. Rearrange the equation and solve.

\(I=\frac{10}{12 \times 10^{-3}}\)

\(I=833.3A\)

\(I\approx830A\)

Finding Charge from Current and Time

A battery supplies 4.7Amps to a bulb over a period of 14 seconds. Calculate the charge leaving the battery in this time correct to two significant figures. A hairdryer uses a current of 7.2A for 5 minutes to dry a person’s hair. Calculate the charge flowing through the hairdryer in this time correct to two significant figures.
1. State the known quantities in correct units.

I = 4.7A

t = 14s

1. State the known quantities in correct units.

I = 7.2A

t = 5min = 300s

2. Substitute the numbers into the equation and solve.

\(Q=It\)

\(Q=4.7 \times 14\)

\(Q = 65.8C\)

\(Q \approx 66C\)

2. Substitute the numbers into the equation and solve.

\(Q=It\)

\(Q=7.2 \times 300\)

\(Q = 2160C\)

\(Q \approx 2200C\)

Finding Time from Current and Charge

A battery charger uses a current of 150mA to deliver a charge of 245 Coloumbs to a battery. Calculate the time taken to charge this battery correct to two significant figures. A cloud in a thunderstorm loses 15C in one lightening strike. At a current of 31,000kA. Calculate how long this lightning strike lasts correct to two significant figures.
1. State the known quantities in correct units.

I = 150mA = 150x10-3A

Q = 245C

1. State the known quantities in correct units.

I = 31,000kA = 3.1x107A

Q = 15C

2. Substitute the numbers and evaluate.

\(Q=It\)

\(245 = 150 \times 10^{-3} \times t\)

2. Substitute the numbers and evaluate.

\(Q=It\)

\(15= 3.1 \times 10^7 \times t\)

3. Rearrange the equation and solve.

\(t=\frac{245}{150 \times 10^{-3}}\)

\(t=1633.3s\)

\(t\approx1633.3s\)

3. Rearrange the equation and solve.

\(t=\frac{15}{3.1 \times 10^7}\)

\(t = 4.8387 \times 10^{-7}s\)

\(t\approx4.8 \times 10^{-7}s\)

Finding Charge from Potential Difference and Energy Transferred

The potential difference of 12V is placed across a resistor increasing its thermal energy store by 3.7J as a result. Calculate the charge that has flowed through the resistor in this time correct to two significant figures. A circuit transfers 2.8kJ of energy electrically to a motor. The potential difference across the motor is 1.5V. Calculate thecharge that has flowed through the motor in this time correct to two significant figures.
1. State the known quantities in correct units.

V = 12V

E = 3.7J

1. State the known quantities in correct units.

V = 1.5V

E = 2.8kJ = 2.8x103J

2. Substitute the numbers into the equation and solve.

\(Q=\frac{E}{V}\)

\(Q=\frac{3.7}{12}\)

\(Q=0.3083C\)

\(Q\approx0.31C\)

2. Substitute the numbers into the equation and solve.

\(Q=\frac{E}{V}\)

\(Q=\frac{2.8 \times 10^3}{1.5}\)

\(Q=1866.7C\)

\(Q\approx1900C\)

Finding Potential Difference from Charge and Energy Transferred

A charge of 84C transfers an energy of 20kJ. Calculate the potential difference correct to two significant figures. 170J of energy is transferred by a charge of 92mC. Calculate the potential difference correct to two significant figures.
1. State the known quantities in correct units.

Q = 84C

E = 20kJ = 20x103J

1. State the known quantities in correct units.

Q = 92mC = 92x10-3C

E = 170J

2. Substitute the numbers and evaluate.

\(Q=\frac{E}{V}\)

\(84=\frac{20 \times 10^3}{V}\)

2. Substitute the numbers and evaluate.

\(Q=\frac{E}{V}\)

\(92 \times 10^{-3}=\frac{170}{V}\)

3. Rearrange the equation and solve.

\(V=\frac{20 \times 10^3}{84}\)

\(V=238.0952V\)

\(V\approx 240V\)

3. Rearrange the equation and solve.

\(V=\frac{170}{92 \times 10^{-3}}\)

\(V=1847.826V\)

\(V\approx 1800V\)

Finding Energy Transferred from Charge and Potential Difference

A bolt of lightning with a potential difference 31,000kV transfers a charge of 15C. Calculate the energy transferred by this bolt of lightning correct to two significant figures. A 9V battery is able to mobilise a charge of 4.3kC during its operation. Calculate the total amount of energy stored in this battery correct to two significant figures.
1. State the known quantities in correct units.

V = 31,000kV = 3.1x107V

Q = 15C

1. State the known quantities in correct units.

V = 9V

Q = 4.3kC = 4.3x103

2. Substitute the numbers and evaluate.

\(Q=\frac{E}{V}\)

\(15=\frac{E}{3.1 \times 10^7}\)

2. Substitute the numbers and evaluate.

\(Q=\frac{E}{V}\)

\(4.3 \times 10^3 =\frac{E}{9}\)

3. Rearrange the equation and solve.

\(E = 15 \times 3.1 \times 10^7\)

\(E = 4.65\times10^8 J\)

\(E\approx4.7\times10^8 J\)

3. Rearrange the equation and solve.

\(E = 4.3 \times 10^3 \times 9\)

\(E = 38700J\)

\(E \approx 39000 \times 10^4J\)

References

AQA

Charge (electrical), pages 46-52, 71, 74-5, GCSE Physics; Student Book, Collins, AQA
Charge; electric, page 24, GCSE Physics; The Revision Guide, CGP, AQA
Charge; electric, pages 180, 189, 190, GCSE Combined Science; The Revision Guide, CGP, AQA
Charge; electric, pages 61, 88-90, GCSE Combined Science Trilogy; Physics, CGP, AQA
Charge; electric, pages 63, 91-93, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Electric charge, page 24, GCSE Physics; The Revision Guide, CGP, AQA
Electric charge, pages 180, 189, 190, GCSE Combined Science; The Revision Guide, CGP, AQA
Electric charge, pages 61, 88-90, GCSE Combined Science Trilogy; Physics, CGP, AQA
Electric charge, pages 63, 91-93, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Electric charge; ions, page 112, GCSE Combined Science Trilogy; Physics, CGP, AQA
Electric charge; ions, page 124, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Electric charge; of an atom, page 111, GCSE Combined Science Trilogy; Physics, CGP, AQA
Electric charge; of an atom, page 123, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Electric charge; relative charge, page 111, GCSE Combined Science Trilogy; Physics, CGP, AQA
Electric charge; relative charge, page 123, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Electric charge; static, pages 99, 103, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA

Edexcel

Charge (electric), page 221, GCSE Physics, CGP, Edexcel
Charge, electrical, pages 144, 160-161, GCSE Physics, Pearson Edexcel
Charge, electrical; energy, page 145, GCSE Physics, Pearson Edexcel
Charge, electrical; point charges, page 164, GCSE Physics, Pearson Edexcel

OCR

Electric charge, pages 94-97, 101, Gateway GCSE Physics, Oxford, OCR

Key Stage 5

Meaning

Electrical charge is a conserved quantity and a property of particles which allow them to interact via the electromagnetic interaction.

About Electrical Charge

The SI Unit of charge is the Coulomb (C).
Charge is a scalar quantity as it has magnitude but does not have a direction.
Charges create an electrostatic field which affects other charged objects.
Charge is a conserved quantity which means; "Charge cannot be created or destroyed, it can only be transferred from one place to another."
A flow of charge is an electrical current.

About Electrical Charge at the Particle Level

Charged particles may exchange virtual photons causing a change in their momentum. This results in the force of attraction or repulsion between charged particles.
As a conserved quantity charge cannot be created or destroyed, but it can be transferred from one particle to another. This occurs in the weak interaction via the W-boson.
The electrical charge passed between subatomic particles during the weak interaction has a magnitude of 1.60x10-19 Coulombs (the elementary charge).
The electrical charge of the proton is +1.60x10-19 Coulombs and the electrical charge of the electron is -1.60x10-19 Coulombs.
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