Transformer Objective Type Question and Answer   

Question 1-  Which of these is the type of loss of transformer?

A. Copper loss
B. Iron loss
 C. Both A and B
D. Gold Loss

Answer-  C. Both A and B.

Question 2- What is the rating of the transformer shown in?

A - K. W.
B - K.Wh.
C - K.V.A.
D - KVAR

Answer-C - K.V.A.

Question 3 - How much phase difference is there between the primary and secondary voltage of a single phase transformer?

A. 90 °
B. 180 °
C. 360 °
D. 120 °

Answer-B. 180 °

Question 4-  What is the composition of steel and silicon steel in transformer core?

A. Steel 97% and silicon 3%
B.  Steel 95% and silicon 5%
C. Steel 93% and silicon 7%
D. Steel 90% and silicon 10%

Answer- C. Steel 93% and silicon 7%.

Question 5- Transformer works on which principle?

A. Faraday Rule
B. Electro Magnetic Induction.
C. Mutual induction.
D. shelf induction.

Answer- C. Mutual induction. 

Question 6-  What is the condition for obtaining maximum efficiency from transformer? 


A. Copper loss > Iron loss
B. Copper loss < Iron loss
C. Copper loss = Iron loss
D. Copper loss =Eddy current loss

Answer- C. Copper loss = Iron loss.

Question 7- Winding is done in single phase transformer. 

A. Four.
B. Three.
C. two.
D. A.

Answer- C. Two.


Question 8-  Which loss of transformer is determined by  short circuit test? 

A. Copper loss
B. Windage loss
C. Hysteresis loss
D. Eddy current loss

Answer- A. Copper loss.

Question 9- Which power loss is assessed by open circuit test on transformer? 

A. Hysteresis loss only
B. Eddy current loss only
C. Copper loss
D. Core loss

Answer- D. Core loss.

Question10-  Which material is used to make core of power transformer? 

A. Soft iron
B. Rolled steel
C. Copper alloy
D. Cold rolled grain oriented

Answer- D. Cold rolled grain oriented.

Question11- What is the advantage of stepped core arrangement in larger transformers? 

A. Minimizes copper use
B. Reduces hysteresis loss
C. Reduces eddy current loss
D. Reduces the space for core

Answer- A. Minimizes copper use.

Question12- How to determine copper loss in a transformer? 

A. Ratio test
B. Impulse test
C. Short circuit test
D. Open circuit test

Answer- C. Short circuit test.

Question13-  Which cooling method is used in pole mounting distribution transformer? 

A. Air natural
B. Oil natural air blast
C. Oil forced air forced
D. Oil natural air natural

Answer- D. Oil natural air natural.


Question14-  Why distribution transformers are normally connected as primary in delta and secondary in star? 

A. To avoid over loading
B. To maintain constant voltage
C. To reduce transformer losses
D. To easy distribution of 3 phase 4 wire system

Answer- D. To easy distribution of 3 phase 4 wire system. 


Question15-  What is the purpose of tap changing in power transformers? 

A. Maintain primary voltage constant
B. Change voltage ratio in distribution
C. Maintain secondary voltage constant
D. Load the transformer for maximum efficiency

Answer- B. Change voltage ratio in distribution.

Question16-  What is the function of buchholz relay in power transformer? 

A. Protection from high temperature
B. Protection from moisture entering in oil
C. Protection from pressure loading in tank
D. Protection from both overloading and short circuit

Answer- D. Protection from both overloading and short circuit.


Question17-  Which construction technique is used to reduce copper loss in larger transformers? 

A. Use of laminated core
B. By reducing core thickness
C. By using grain oriented core
D. Use stepped core arrangement

Answer- D. Use stepped core arrangement.

Question18-  How the error in reading of a potential transformer can be reduced? 

A. Using thin laminated core
B. Providing long magnetic path
C. Using high flux density material
D. Providing good quality core material.

Answer- D. Providing good quality core material.