4.5.6. The transformer
A subsection of Physics, 0625, through 4. Electricity and magnetism
Listing 10 of 232 questions
10 Alternating current electricity is delivered at 22 000 V to a pair of transmission lines. The transmission lines carry the electricity to the customer at the receiving end, where the potential difference is V. This is shown in . Each transmission line has a resistance of 3 Ω. 22 000 V V 3 Ω 3 Ω The a.c. generator actually generates at a much lower voltage than 22 000 V. Suggest how the voltage is increased to 22 000 V. State one advantage of delivering electrical energy at high voltage. The power delivered by the generator is 55 kW. Calculate the current in the transmission lines. current = Calculate the rate of loss of energy from one of the 3 Ω transmission lines. rate of energy loss = Calculate the voltage drop across one of the transmission lines. voltage drop = Calculate the potential difference V at the receiving end of the transmission lines. V = .
0625_w09_qp_31
THEORY
2009
Paper 3, Variant 1
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10 Alternating current electricity is delivered at 22 000 V to a pair of transmission lines. The transmission lines carry the electricity to the customer at the receiving end, where the potential difference is V. This is shown in . Each transmission line has a resistance of 3 . 22 000 V V 3 X 3 X The a.c. generator actually generates at a much lower voltage than 22 000 V. Suggest how the voltage is increased to 22 000 V. State one advantage of delivering electrical energy at high voltage. The power delivered by the generator is 55 kW. Calculate the current in the transmission lines. current = Calculate the rate of loss of energy from one of the 3  transmission lines. rate of energy loss = Calculate the voltage drop across one of the transmission lines. voltage drop = Calculate the potential difference V at the receiving end of the transmission lines. V = .
0625_w09_qp_32
THEORY
2009
Paper 3, Variant 2
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Electrical power is produced in a power station by an alternating current (a.c.) generator. The output of the generator has a voltage of 22 000 V. The electrical power is transmitted at a voltage of 400 000 V. Explain why electrical power is transmitted at a voltage of 400 000 V and not 22 000 V. A computer contains a transformer. The input voltage to the transformer is 240 V. The output voltage from the transformer is 20 V and the output current is 2.3 A. The efficiency of the transformer is 90%. Calculate the input current to the transformer. current =
0625_w20_qp_43
THEORY
2020
Paper 4, Variant 3
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Questions Discovered
232