890549
Pregunta 1
Pregunta
True or false? In alternating current, the potential difference switches between positive and negative values.
Respuesta
- True
- False
Pregunta 2
Pregunta
Which of these statements are true about the UK mains supply?
Respuesta
-
Frequency of 50Hz
-
Frequency of 60Hz
-
Peak voltages of +230 and -230V
-
Peak voltages of +325 and -325V
-
Direct voltage of 230V
-
Direct voltage of 325V
Pregunta 3
Pregunta
True or false? The device used to show how alternating potential difference varies with time is called a voltascope.
Respuesta
- True
- False
Pregunta 4
Pregunta
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?
Respuesta
-
2.55V
-
4.53V
-
4.15V
-
2.65V
Pregunta 5
Pregunta
What is the frequency of an AC supply if the length of one cycle is 4cm and the time-base control is 15ms/cm?
Respuesta
-
60Hz
-
0.06Hz
-
16.67Hz
-
0.02Hz
Pregunta 6
Pregunta
What colour cable is the live wire in a three-core cable?
Respuesta
-
Green and yellow
-
Brown
-
Blue
Pregunta 7
Pregunta
What colour cable is the neutral wire in a three-core cable?
Respuesta
-
Green and yellow
-
Brown
-
Blue
Pregunta 8
Pregunta
What colour cable is the earth wire in a three-core cable?
Respuesta
-
Green and yellow
-
Brown
-
Blue
Pregunta 9
Pregunta
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.
Respuesta
- True
- False
Pregunta 10
Pregunta
True or false? A circuit breaker is a piece of metal that melts if the current flowing through it is too large.
Respuesta
- True
- False
Pregunta 11
Pregunta
What fuse would you need to buy if an appliance drew 2.7A of current?
Respuesta
-
1A
-
2A
-
3A
-
5A
-
13A
Pregunta 12
Pregunta
True or false? Residual current circuit breakers break if the current in the live wire is different to the current in the neutral wire.
Respuesta
- True
- False
Pregunta 13
Pregunta
Which of these equations connecting power, energy and time is correct?
Respuesta
-
P = E/t
-
P = t/E
-
P = Et
Pregunta 14
Pregunta
Which of these equations connecting power, current and potential difference is correct?
Respuesta
-
P = I/V
-
P = V/I
-
P = IV
Pregunta 15
Pregunta
What fuse would I buy if I bought a 230V, 1000W appliance?
Respuesta
-
1A
-
2A
-
3A
-
5A
-
13A
Pregunta 16
Pregunta
How many units of charge would each electron carry if they carried 6A of current in 1 minute?
Respuesta
-
10C
-
0.1C
-
360C
Pregunta 17
Pregunta
True or false? The equation connecting charge, potential difference and energy is Q = VE.
Respuesta
- True
- False
Pregunta 18
Pregunta
What would be the potential difference of circuit in which 2000J of energy were carried by electrons with a charge of 4C?
Respuesta
-
8000V
-
500V
-
0.002V
Pregunta 19
Pregunta
True or false? Connecting too many appliances to a single socket can lead to overheating.
Respuesta
- True
- False
Pregunta 20
Pregunta
Which of these are considered energy-efficient bulbs?
Respuesta
-
Filament bulb
-
Compact fluorescent bulbs
-
Light-emitting diodes
-
Halogen bulbs
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