2562068
Description
Quiz by giannini.chambers, updated more than 1 year ago
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Created by giannini.chambers
over 9 years ago
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Question 1
Question
An inductor of 300mH placed on a 60Hz network will have an inductive reactance of?
Answer
-
113Ω
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100Ω
-
113097Ω
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97Ω
Question 2
Question
A capacitor of 90µF is placed on an electrical network of frequency 65 Hz. What is the value of capacitive reactance?
Answer
-
27Ω
-
27000000Ω
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27000Ω
-
0.0027Ω
Question 3
Question
What is the typical generation voltage at a power station?
Answer
-
25kV
-
125kV
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11kV
-
33kV
Question 4
Question
Where is the neutral connected on the secondary of a delta to star transformer?
Answer
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The end of every line
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The star point of the transformer
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To the middle of every winding
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Left floating
Question 5
Question
What is the phase separation angle in a typical star system between phases?
Answer
-
100°
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120°
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360°
-
110°
Question 6
Question
A voltage of 700V is applied to two resistors in series. A current of 2.8A flows. If one of the resistors is 150Ω what is the value of the other?
Answer
-
100Ω
-
50Ω
-
75Ω
-
124Ω
Question 7
Question
What is the series impedance of a circuit where the resistance is 30Ω the inductive reactance is 70Ω and the capacitive reactance is 30Ω?
Answer
-
50Ω
-
65Ω
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70Ω
-
40Ω
Question 8
Question
If you have a star phase voltage of 135V what would the line voltage be?
Answer
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234V
-
200V
-
78V
-
75V
Question 9
Question
A 30kW lift motor is running at 0.95 power factor. Calculate the line current that is drawn from the supply when the voltage is 390V:
Answer
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47A
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40A
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37A
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50A
Question 10
Question
What type of light fitting requires no control gear?
Answer
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Incandescent
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Fluorescent
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Sodium Discharge
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High pressure mercury
Question 11
Question
Which type of protective device natively offers the functions of earth fault, residual current and short circuit protection?
Answer
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RCBO
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MCB
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RCD
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ACB
Question 12
Question
A light source of 300 Candela is placed 2.5m above a table. Calculate the illuminance at a point directly below the light fitting.
Answer
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48 Lux
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48 Lumens
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120 Lux
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120 Lumens
Question 13
Question
The full load current of a transformer is 650A and the voltage is 400V between phases. Calculate the apparent power rating of the transformer.
Answer
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450kVA
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400kVA
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180kVA
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400kW
Question 14
Question
In a TT system the means of earthing is provided by:
Answer
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Distributor's earth supply
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Installation earth electrode
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Combined neutral and earth
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None it is an earth free location
Question 15
Question
The phase voltage supplied to a building is 270V. The building is given a 3 phase 3 wire supply. What voltage are available to work with?
Answer
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270V and 468V
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468V
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270V, 468V and 135V
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300V
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300V and 500V
Question 16
Question
Calculate the angle the current lags the voltage in a network where there is 30kW and 12kVAr on the network.
Answer
-
21.8°
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18°
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25°
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26.7°
Question 17
Question
A centre tapped to earth transformer has a voltage of 75V phase to earth. What would the full voltage available be?
Answer
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150V
-
100V
-
37.5V
-
130V
Question 18
Question
A 25kW load is being drawn from a supply at 350V. Calculate the power loss through the conductor if the resistance is measured at 0.3Ω.
Answer
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1000W
-
1640W
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1530W
-
2160W
Question 19
Question
The potential difference between a cat and the earth is 1000V. If the resistance of the cat is measured at 250Ω what would the current flow to earth be?
Answer
-
10A
-
250000A
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4V
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4A
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