4.2.5. Electrical energy and electrical power
A subsection of Physics, 0625, through 4. Electricity and magnetism
Listing 10 of 62 questions
shows an electric kettle. The power input of the kettle is 1.5 kW. The potential difference of the mains electrical supply for the kettle is 220 V. Calculate the current in the kettle when it is switched on. current in kettle = A The 1.5 kW kettle is used for a total of 4.0 hours. The cost of 1.0 kW h of electrical energy is 14 pennies . Calculate the cost of the energy used by the kettle in 4.0 hours. cost of energy = p shows an overloaded extension lead. Explain the danger of connecting too many plugs to an extension lead.
0625_m23_qp_32
THEORY
2023
Paper 3, Variant 2
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The power supply used in an electric vehicle contains 990 rechargeable cells each of electromotive force (e.m.f.) 1.2 V. The cells are contained in packs in which all the cells are in series with each other. The e.m.f. of each pack is 54 V. Calculate the number of packs in the power supply. number of packs = When in use, each pack supplies a current of 3.5 A. Calculate the rate at which each cell is transferring chemical energy to electrical energy. rate of energy transfer = The packs are connected in parallel to supply a large current to drive the electric vehicle. Explain why it is necessary to use thick wires to carry this current.
0625_s20_qp_41
THEORY
2020
Paper 4, Variant 1
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Questions Discovered
62