A-Level H2 物理筆記
Chapter 19: Practical Electricity
Electric power and energy
Dangers of electricity
Safe use of electricity in the home
(a) Describe the use of the heating effect of electricity in appliances such as electric kettles, ovens and heaters.
(b) Recall and apply the relationships P = VI and E = VI t to new situations or to solve related problems.
(c) Calculate the cost of using electrical appliances where the energy unit is the kW h.
(d) Compare the use of non-renewable and renewable energy sources such as fossil fuels, nuclear energy, solar energy, wind energy and hydroelectric generation to generate electricity in terms of energy conversion efficiency, cost per kW h produced and environmental impact.
(e) State the hazards of using electricity in the following situations:
(i) damaged insulation
(ii) overheating of cables
(iii) damp conditions
(f) Explain the use of fuses and circuit breakers in electrical circuits and of fuse ratings.
(g) Explain the need for earthing metal cases and for double insulation.
(h) State the meaning of the terms live, neutral and earth.
(i) Describe the wiring in a mains plug.
(j) Explain why switches, fuses, and circuit breakers are wired into the live conductor.