Transformers MCQs (Part-7)

What does a step-down transformer do?

A Increases voltage
B Reduces voltage
C Increases current
D Reduces current

What is the main function of an autotransformer?

A To convert AC to DC
B To share a common winding between primary and secondary circuits
C To isolate circuits
D To provide electrical protection

Which type of transformer is most commonly used for residential applications?

A Power transformer
B Distribution transformer
C Isolation transformer
D Autotransformer

What is the main characteristic of dry-type transformers?

A They use oil as a coolant
B They do not use liquid for cooling
C They are designed for high-voltage applications only
D They require external cooling

What is the primary use of an oil-filled transformer?

A To store electrical energy
B To provide insulation and cooling
C To step up voltage
D To step down voltage

What is inrush current in a transformer?

A The current that flows through the secondary winding under load
B The surge of current when the transformer is first energized
C The current required to maintain the magnetic field
D The current used to heat the core

What is the purpose of a transformer’s core?

A To increase voltage
B To guide the magnetic flux
C To insulate the windings
D To store electrical energy

What type of transformer is used to isolate electrical circuits from each other?

A Step-up transformer
B Isolation transformer
C Distribution transformer
D Autotransformer

What does the “magnetizing current” in a transformer refer to?

A The current required to power the load
B The current required to magnetize the core of the transformer
C The current flowing in the secondary winding
D The current caused by an overload

Which test is used to measure the core loss in a transformer?

A Short-circuit test
B Open-circuit test
C Load test
D Impedance test

What is the purpose of a transformer’s core?

A To increase voltage
B To guide the magnetic flux
C To insulate the windings
D To store electrical energy

What type of transformer is used to isolate electrical circuits from each other?

A Step-up transformer
B Isolation transformer
C Distribution transformer
D Autotransformer

What does the “magnetizing current” in a transformer refer to?

A The current required to power the load
B The current required to magnetize the core of the transformer
C The current flowing in the secondary winding
D The current caused by an overload

Which test is used to measure the core loss in a transformer?

A Short-circuit test
B Open-circuit test
C Load test
D Impedance test

What is the purpose of a transformer’s core?

A To increase voltage
B To guide the magnetic flux
C To insulate the windings
D To store electrical energy

What type of transformer is used to isolate electrical circuits from each other?

A Step-up transformer
B Isolation transformer
C Distribution transformer
D Autotransformer

What does the “magnetizing current” in a transformer refer to?

A The current required to power the load
B The current required to magnetize the core of the transformer
C The current flowing in the secondary winding
D The current caused by an overload

Which test is used to measure the core loss in a transformer?

A Short-circuit test
B Open-circuit test
C Load test
D Impedance test

What is the main advantage of using dry-type transformers?

A Higher voltage ratings
B Reduced fire risk
C Better cooling performance
D Higher efficiency

What is the most common method of cooling used in large transformers?

A Air cooling
B Oil cooling
C Liquid nitrogen cooling
D Water cooling