Which of the following is the primary function of a transformer?
a) Convert mechanical energy to electrical energy
b) Change the voltage level of AC power
c) Convert AC to DC
d) Store electrical energy
A step-up transformer does which of the following?
a) Increases voltage
b) Decreases voltage
c) Converts AC to DC
d) Stores charge
What type of transformer is used in power transmission lines?
a) Isolation transformer
b) Step-down transformer
c) Auto-transformer
d) Step-up transformer
Which law explains the working principle of transformers?
a) Faraday’s Law of Electromagnetic Induction
b) Ohm’s Law
c) Newton’s Law
d) Kirchhoff’s Law
What is the main cause of energy loss in transformers?
a) Magnetic hysteresis
b) Friction
c) Mechanical wear
d) Nuclear reaction
Power transmission at high voltage reduces which of the following?
a) Power loss
b) Efficiency
c) Resistance
d) Magnetic fields
Which material is used for transformer cores to minimize energy loss?
a) Copper
b) Silicon steel
c) Aluminum
d) Plastic
A step-down transformer is used to:
a) Increase current and decrease voltage
b) Increase voltage and decrease current
c) Convert DC to AC
d) Store electrical charge
Why is AC power preferred for long-distance transmission?
a) It is easier to generate
b) Transformers work only with AC
c) AC power is safer than DC
d) AC power has no losses
What is the efficiency of a well-designed transformer?
a) 50-60%
b) 70-80%
c) 90-99%
d) 100%
Which of the following is not a part of a transformer?
a) Primary coil
b) Secondary coil
c) Commutator
d) Iron core
What does a transformer do in an electrical substation?
a) Converts DC to AC
b) Stores electrical energy
c) Changes voltage level
d) Generates electricity
The voltage transformation ratio of a transformer is given by:
a) Primary turns / Secondary turns
b) Secondary turns / Primary turns
c) Power input / Power output
d) Resistance / Reactance
What is the purpose of transformer oil?
a) To provide insulation and cooling
b) To conduct electricity
c) To increase voltage
d) To decrease power loss
Which type of transformer has only one winding?
a) Step-up transformer
b) Auto-transformer
c) Step-down transformer
d) Isolation transformer
What happens when a transformer operates with DC input?
a) It works efficiently
b) It gets damaged due to high current
c) It produces high voltage
d) It stores electrical energy
What is the main reason for using laminated iron cores in transformers?
a) To reduce weight
b) To minimize eddy current losses
c) To increase magnetic field
d) To decrease voltage
What happens when a load is connected to a transformer’s secondary coil?
a) Voltage increases
b) Current flows
c) Magnetic field disappears
d) Transformer stops working
Which of the following materials is commonly used for transformer windings?
a) Iron
b) Plastic
c) Copper
d) Wood
Which transformer connection is commonly used in power distribution systems?
a) Star-Delta
b) Delta-Delta
c) Star-Star
d) Delta-Star
Which transformer loss is due to repeated magnetization and demagnetization of the core?
a) Eddy current loss
b) Hysteresis loss
c) Copper loss
d) Load loss
What is the purpose of a potential transformer?
a) To increase power output
b) To measure high voltage
c) To decrease resistance
d) To store charge
Which factor affects the efficiency of a transformer the most?
a) Core material
b) Cooling system
c) Winding resistance
d) All of the above
What happens if a transformer is overloaded?
a) It operates normally
b) It overheats and may get damaged
c) Voltage increases
d) Resistance decreases
Which of the following is not a type of transformer?
a) Power transformer
b) Instrument transformer
c) Rectifier transformer
d) Solar transformer
Which component is added in transformers for voltage regulation?
a) Tap changer
b) Resistor
c) Fuse
d) Circuit breaker
Which of the following is an application of transformers?
a) Mobile charging
b) Electric trains
c) Power distribution
d) All of the above
What happens if the turns ratio of a transformer is greater than 1?
a) It is a step-up transformer
b) It is a step-down transformer
c) It acts as an isolator
d) It stops working
What is the main reason for using transformers in power transmission?
a) To increase efficiency and reduce power loss
b) To generate more electricity
c) To decrease transmission speed
d) To increase electrical resistance
