Q. In a step-up transformer, the number of turns in the primary winding is:
-
A.
Greater than the secondary winding
-
B.
Less than the secondary winding
-
C.
Equal to the secondary winding
-
D.
None of the above
Solution
In a step-up transformer, the primary winding has fewer turns than the secondary winding.
Correct Answer:
B
— Less than the secondary winding
Learn More →
Q. What is the effect of increasing the frequency on the size of a transformer?
-
A.
Increases size
-
B.
Decreases size
-
C.
No effect
-
D.
Depends on the load
Solution
Increasing the frequency allows for a smaller transformer size due to reduced core losses.
Correct Answer:
B
— Decreases size
Learn More →
Q. What is the effect of increasing the load on a transformer?
-
A.
Increases efficiency
-
B.
Decreases efficiency
-
C.
No effect on efficiency
-
D.
Increases voltage output
Solution
Increasing the load on a transformer can lead to increased losses, thus decreasing efficiency.
Correct Answer:
B
— Decreases efficiency
Learn More →
Q. What is the main cause of energy losses in transformers?
-
A.
Copper losses
-
B.
Iron losses
-
C.
Stray losses
-
D.
All of the above
Solution
Energy losses in transformers are caused by copper losses, iron losses, and stray losses.
Correct Answer:
D
— All of the above
Learn More →
Q. What is the main function of a transformer in a power distribution system?
-
A.
To generate electricity
-
B.
To convert AC to DC
-
C.
To step down high voltage for safe distribution
-
D.
To store energy
Solution
In a power distribution system, transformers step down high voltage to safer levels for distribution.
Correct Answer:
C
— To step down high voltage for safe distribution
Learn More →
Q. What is the main purpose of using a transformer in power distribution?
-
A.
To increase current
-
B.
To decrease losses during transmission
-
C.
To convert AC to DC
-
D.
To store energy
Solution
Transformers are used in power distribution to decrease losses during transmission by increasing voltage levels.
Correct Answer:
B
— To decrease losses during transmission
Learn More →
Q. What is the primary material used in the core of a transformer?
-
A.
Copper
-
B.
Aluminum
-
C.
Silicon steel
-
D.
Iron
Solution
The primary material used in the core of a transformer is silicon steel, which has good magnetic properties.
Correct Answer:
C
— Silicon steel
Learn More →
Q. What is the purpose of a tap changer in a transformer?
-
A.
To change the frequency
-
B.
To adjust the voltage ratio
-
C.
To increase efficiency
-
D.
To reduce harmonics
Solution
A tap changer is used to adjust the voltage ratio of a transformer to maintain the desired output voltage.
Correct Answer:
B
— To adjust the voltage ratio
Learn More →
Q. What is the typical efficiency range of a power transformer?
-
A.
70% - 80%
-
B.
80% - 90%
-
C.
90% - 98%
-
D.
98% - 100%
Solution
Power transformers typically have an efficiency range of 90% to 98%.
Correct Answer:
C
— 90% - 98%
Learn More →
Q. What is the typical efficiency range of a well-designed transformer?
-
A.
50% - 60%
-
B.
70% - 80%
-
C.
90% - 99%
-
D.
100% - 110%
Solution
Well-designed transformers typically have an efficiency range of 90% to 99%.
Correct Answer:
C
— 90% - 99%
Learn More →
Q. What type of transformer is used for impedance matching?
-
A.
Step-up transformer
-
B.
Step-down transformer
-
C.
Isolation transformer
-
D.
Autotransformer
Solution
An isolation transformer is often used for impedance matching in circuits.
Correct Answer:
C
— Isolation transformer
Learn More →
Q. Which of the following losses is predominant in a transformer?
-
A.
Copper loss
-
B.
Iron loss
-
C.
Stray loss
-
D.
Dielectric loss
Solution
Copper loss (I²R loss) and iron loss (hysteresis and eddy current losses) are predominant in transformers, but iron loss is often more significant.
Correct Answer:
B
— Iron loss
Learn More →
Q. Which type of transformer is used for impedance matching?
-
A.
Step-up transformer
-
B.
Step-down transformer
-
C.
Isolation transformer
-
D.
Autotransformer
Solution
An isolation transformer is used for impedance matching and to isolate different parts of a circuit.
Correct Answer:
C
— Isolation transformer
Learn More →
Showing 1 to 13 of 13 (1 Pages)
