871228
Description
Quiz by Vito Martino, updated more than 1 year ago
|
|
Created by Vito Martino
over 10 years ago
|
|
Question 1
Question
Which of the following formulas can calculate power in an ac circuit?
Answer
-
P = V x I x pf
-
P = V + I
-
P = V x I
-
P = V/R
Question 2
Question
What is the power produced by a 400v three phase system which delivers 25A at a power factor of 0.85
Answer
-
14.72kW
-
6.23kW
-
10kW
-
14kW
Question 3
Question
What is the power produced by a 400v three phase system which delivers 10A at a power factor of 0.7
Answer
-
4849.6W
-
4.7kW
-
5000W
-
4700W
Question 4
Question
The power factor of an installation can be calculated from
Answer
-
Cosθ = Z/X
-
Cosθ = X/Z
-
Cosθ = KVA/KW
-
Cosθ = KW/KVA
Question 5
Question
The power factor of an inductive load can be improved by?
Answer
-
Connecting a inductor across the load
-
Connecting a resistor in parallel with the load
-
Connecting a capacitor in series with the load
-
Connecting a capacitor across the load (parallel)
Question 6
Question
The power factor of a load consisting of inductance and resistance can be calculated from
Answer
-
Cosθ = True Power/Apparent Power
-
Cosθ = Apparent Power/ Reactive Power
-
Cosθ = Reactive Power/True Power
-
Cosθ = Apparent Power/True Power
Question 7
Question
The formula required to calculate the total power of a single phase inductive load supplied by an a.c. supply is
Answer
-
P = IV sinθ
-
P = IV
-
P = IV tanθ
-
P = IV cosθ
Question 8
Question
If the W is 100 and the VA is 120 what would the power factor be
Answer
-
0.75
-
0.2
-
0.85
-
0.83
Question 9
Question
If the kW is 200 and the KVA is 400 what would the power factor be?
Answer
-
0.6
-
0.7
-
0.8
-
0.5
Question 10
Question
A single phase circuit draws a current of 21.7A from a 230 V circuit at a power factor of 0.4
What is the current drawn if the power factor is corrected to 0.85
Answer
-
18.4 A
-
23.4 A
-
10.21 A
-
21.7 A
Question 11
Question
A circuit dissipates 2000 W at a power factor of 0.5 when connected to a 230 V ac supply. The current drawn from the supply is
Answer
-
17.8 A
-
17.39 A
-
4.3 A
-
8.7 A
Question 12
Question
A circuit dissipates 1.5 kW at a power factor of 0.75 when connected to a 230V ac supply. The current drawn from the supply is
Answer
-
7.8 A
-
9.2 A
-
6.5 A
-
8.7 A
Question 13
Question
A three phase system gives the following readings
kVA =30 kW= 45
What is the power factor for the system
Answer
-
0.67
-
unity
-
1.5
-
0.8
Question 14
Question
A three phase system gives the following readings
kW= 400 kVA = 500
What is the power factor for the system
Answer
-
1.25
-
unity
-
0.8
-
0.6
Question 15
Question
What unit is reactive power measured in
Answer
-
kA
-
KVAr
-
kW
-
KVA
Question 16
Question
What unit is apparent power measured in
Answer
-
kA
-
KVAr
-
kW
-
KVA
Question 17
Question
What unit is true power measured in
Answer
-
KVAr
-
kA
-
kW
-
KVA
Question 18
Question
Which component would cause the current and voltage to behave as above
Image:
Slide2.JPG (image/JPG)
Answer
-
resistor
-
rectifier
-
capacitor
-
Inductor
Question 19
Question
Which component would cause the current and voltage to behave as above
Image:
Slide1.JPG (image/JPG)
Answer
-
Inductor
-
capacitor
-
resistor
-
rectifier
Question 20
Question
Which component would cause the current and voltage to behave as above
Image:
Slide3.JPG (image/JPG)
Answer
-
Inductor
-
capacitor
-
resistor
-
rectifier
Want to create your own Quizzes for free with GoConqr? Learn more.