Selina Concise ICSE Solutions for Class 8 Physics Chapter 8 Electricity • ELECTRICITY: “Is the rate of flow of electrons”. i = • To keep electrons move, potential difference is needed. This is done by a cell or battery. • Potential difference “is the amount of work done in moving a unit positive charge from one point to other.” Potential difference V = Work done (W) / charge moved (Q) Or W = QV but charge = it Hence, W = VIt or Electrical energy = VIt • Power is “Rate of doing work” P = W/t = VIt/t = VI Power is measured in watt or J S-1 1 Watt = 1 Volt × 1 Ampere • S.I. unit of charge is coulomb (C). S.I. unit of current is Ampere (A). S.I. unit of P.D. is volt. S.I. unit of electrical energy is Joule (J) and of power is watt (W) 1 kWh-3600000J = 3.6 x 106 J • ELECTRIC power is generated at the GENERATING STATION at 11000 volt, or 11 kV as these stations are at v...
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