Questão 1
Questão
True or false? In alternating current, the potential difference switches between positive and negative values.
Questão 2
Questão
Which of these statements are true about the UK mains supply?
Questão 3
Questão
True or false? The device used to show how alternating potential difference varies with time is called a voltascope.
Questão 4
Questão
What is the peak voltage of an AC supply whose peak is 3.4cm from the centre and whose Y-gain control is 0.75V/cm?
Questão 5
Questão
What is the frequency of an AC supply if the length of one cycle is 4cm and the time-base control is 15ms/cm?
Responda
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60Hz
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0.06Hz
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16.67Hz
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0.02Hz
Questão 6
Questão
What colour cable is the live wire in a three-core cable?
Responda
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Green and yellow
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Brown
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Blue
Questão 7
Questão
What colour cable is the neutral wire in a three-core cable?
Responda
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Green and yellow
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Brown
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Blue
Questão 8
Questão
What colour cable is the earth wire in a three-core cable?
Responda
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Green and yellow
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Brown
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Blue
Questão 9
Questão
True or false? Appliances with plastic cases such as hairdryers only need two-core cable as they are doubly-insulated and do not need to be earthed.
Questão 10
Questão
True or false? A circuit breaker is a piece of metal that melts if the current flowing through it is too large.
Questão 11
Questão
What fuse would you need to buy if an appliance drew 2.7A of current?
Questão 12
Questão
True or false? Residual current circuit breakers break if the current in the live wire is different to the current in the neutral wire.
Questão 13
Questão
Which of these equations connecting power, energy and time is correct?
Questão 14
Questão
Which of these equations connecting power, current and potential difference is correct?
Questão 15
Questão
What fuse would I buy if I bought a 230V, 1000W appliance?
Questão 16
Questão
How many units of charge would each electron carry if they carried 6A of current in 1 minute?
Questão 17
Questão
True or false? The equation connecting charge, potential difference and energy is Q = VE.
Questão 18
Questão
What would be the potential difference of circuit in which 2000J of energy were carried by electrons with a charge of 4C?
Questão 19
Questão
True or false? Connecting too many appliances to a single socket can lead to overheating.
Questão 20
Questão
Which of these are considered energy-efficient bulbs?