a) Units
b) Mains electricity
c) Energy and potential difference in circuits
d) Electric charge
Students will be assessed on their ability to:
S.No | Quantity | Definition | unit | Representation of unit |
---|---|---|---|---|
1 |
Current (I) |
"Flow of charges Or Flow of electrons" However, if definition is asked in exam then only write the following formula Current = Charge / time |
Ampere | A |
2 |
Electric Charge (Q) |
Definition is beyond IGCSE What you need to know is that there are two types of charges i) Positive (+) and ii) Negative (-) |
Coulomb | C |
3 |
Energy (E) |
Energy: Ability to do something. Note1: There are several forms of energy like sound,light,nuclear etc and all of them are measured in Joules. Note2:Energy is a scalar quantity ie it has no direction. |
Joule | J |
4 | Work done (W or E) |
Exam definition Work done = Force x distance moved Note1: It is a scalar quantity Note2: whenever work is done energy is always transferred one form to another. Therefore, Work done = Energy transferred |
Joule | J |
5 | Resistance (R) |
Property of an object to resist the flow of electron or current. However, if definition is required in exam then write its formula in words as shown below Resistance = Voltage / Current symbolically, R = V / I Note1: Resistance in circuits is represented by a rectangular box called resistor. Note2:All materials offer resistance to current. Objects which are made up of insulating materials like wood or less conducting material like iron have less resistance. |
Ohm | Ω |
6 | Time (t) |
Definition is beyond GCSE. | Second | s |
7 | Potential Difference (V) |
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Volt | V |
8 | Power (P) |
Rate of doing work or Rate of energy transferred. However, in exam just write the following formula in words Power = Work done / time |
Watt or Joule/Second 1 W = 1 J/s |
W or 1 J/S |