PAST APAPER Electric Sub Inspector PPSC [SOLVED]
1. What is the unit of electrical resistance?
A) Volt
B) Ampere
C) Ohm
D) Watt
Answer: C) Ohm
2. The primary purpose of a transformer is to:
A) Convert DC to AC
B) Increase or decrease voltage
C) Store energy
D) Measure current
Answer: B) Increase or decrease voltage
3. Which of the following is a common type of electrical circuit?
A) Series circuit
B) Parallel circuit
C) Both A and B
D) None of the above
Answer: C) Both A and B
4. What does the term “AC” stand for in electrical engineering?
A) Alternating Current
B) Average Current
C) Absolute Current
D) Amplified Current
Answer: A) Alternating Current
5. The formula for calculating electrical power (P) is:
A) P = V + I
B) P = V x I
C) P = V / I
D) P = I x R
Answer: B) P = V x I
6. Which device is used to measure electrical current?
A) Voltmeter
B) Ammeter
C) Ohmmeter
D) Wattmeter
Answer: B) Ammeter
7. The frequency of the standard electrical supply in Pakistan is:
A) 50 Hz
B) 60 Hz
C) 100 Hz
D) 110 Hz
Answer: A) 50 Hz
8. What is the purpose of a circuit breaker?
A) To increase voltage
B) To protect circuits from overload
C) To store electricity
D) To measure resistance
Answer: B) To protect circuits from overload
9. The electric field strength (E) is measured in:
A) Volts
B) Amperes
C) Newtons
D) Volts per meter
Answer: D) Volts per meter
10. Which component stores electrical energy in an electric field?
A) Resistor
B) Capacitor
C) Inductor
D) Diode
Answer: B) Capacitor
11. The relationship between voltage (V), current (I), and resistance (R) is defined by:
A) Kirchhoff’s Law
B) Ohm’s Law
C) Faraday’s Law
D) Coulomb’s Law
Answer: B) Ohm’s Law
12. Which of the following materials is a good conductor of electricity?
A) Rubber
B) Glass
C) Copper
D) Wood
Answer: C) Copper
13. What is the function of a diode in a circuit?
A) To amplify signals
B) To allow current to flow in one direction
C) To store energy
D) To measure voltage
Answer: B) To allow current to flow in one direction
14. Which device converts electrical energy into mechanical energy?
A) Generator
B) Motor
C) Transformer
D) Resistor
Answer: B) Motor
15. The formula for calculating the total resistance (R) in a series circuit is:
A) R = R1 + R2
B) R = R1 x R2
C) R = R1 / R2
D) R = R1 – R2
Answer: A) R = R1 + R2
16. The unit of electric charge is:
A) Coulomb
B) Volt
C) Ohm
D) Ampere
Answer: A) Coulomb
17. In a parallel circuit, the total current (I) is:
A) Equal to the sum of the currents through each branch
B) Equal to the voltage across the circuit
C) Equal to the resistance
D) None of the above
Answer: A) Equal to the sum of the currents through each branch
18. Which of the following is an advantage of AC over DC?
A) Easier to generate
B) Can be transmitted over long distances with less loss
C) Simpler circuitry
D) Both A and B
Answer: D) Both A and B
19. What does a potentiometer measure?
A) Voltage
B) Current
C) Resistance
D) Power
Answer: A) Voltage
20. The main function of an inductor is to:
A) Store energy in a magnetic field
B) Store energy in an electric field
C) Measure current
D) Regulate voltage
Answer: A) Store energy in a magnetic field
21. The symbol for a capacitor in a circuit diagram is:
A) A straight line
B) Two parallel lines
C) A zigzag line
D) A triangle
Answer: B) Two parallel lines
22. What is the purpose of a fuse in an electrical circuit?
A) To increase current
B) To limit voltage
C) To protect against overloads
D) To measure resistance
Answer: C) To protect against overloads
23. The power factor of an electrical system is defined as:
A) The ratio of real power to apparent power
B) The ratio of apparent power to reactive power
C) The ratio of reactive power to real power
D) The total power consumed
Answer: A) The ratio of real power to apparent power
24. The SI unit of voltage is:
A) Ohm
B) Ampere
C) Volt
D) Watt
Answer: C) Volt
25. Which type of motor is commonly used in electric fans?
A) DC motor
B) AC motor
C) Stepper motor
D) Synchronous motor
Answer: B) AC motor
26. Which of the following is a semiconductor material?
A) Copper
B) Silicon
C) Aluminum
D) Gold
Answer: B) Silicon
27. The term “ground” in electrical systems refers to:
A) The positive terminal of a battery
B) A reference point for voltage
C) The negative terminal of a battery
D) The source of current
Answer: B) A reference point for voltage
28. What is the main purpose of a relay in a circuit?
A) To amplify signals
B) To switch circuits on or off
C) To store energy
D) To measure current
Answer: B) To switch circuits on or off
29. The main component of a battery is:
A) Electrolyte
B) Capacitor
C) Inductor
D) Resistor
Answer: A) Electrolyte
30. Which law states that the current flowing through a conductor is directly proportional to the voltage across it?
A) Faraday’s Law
B) Ohm’s Law
C) Kirchhoff’s Law
D) Coulomb’s Law
Answer: B) Ohm’s Law
31. The device that converts mechanical energy into electrical energy is called a:
A) Motor
B) Generator
C) Transformer
D) Capacitor
Answer: B) Generator
32. Which of the following is the primary function of a rectifier?
A) Convert AC to DC
B) Convert DC to AC
C) Measure resistance
D) Increase voltage
Answer: A) Convert AC to DC
33. The term “impedance” in AC circuits is equivalent to:
A) Resistance in DC circuits
B) Reactance
C) Both A and B
D) None of the above
Answer: C) Both A and B
34. The efficiency of an electrical machine is defined as:
A) Output power divided by input power
B) Input power divided by output power
C) Total power consumed
D) Real power divided by apparent power
Answer: A) Output power divided by input power
35. Which of the following is a disadvantage of DC power?
A) Difficult to generate
B) Cannot be transformed to higher voltages
C) More expensive
D) All of the above
Answer: B) Cannot be transformed to higher voltages
36. The total resistance in a parallel circuit is:
A) Always greater than the smallest resistor
B) Always less than the smallest resistor
C) Equal to the sum of all resistors
D) Cannot be determined
Answer: B) Always less than the smallest resistor
37. What is the primary function of a fuse?
A) To increase voltage
B) To provide a safety mechanism
C) To regulate current
D) To amplify signals
Answer: B) To provide a safety mechanism
38. The term “reactive power” refers to:
A) Power consumed in resistive loads
B) Power that does no useful work
C) Total power in a circuit
D) Both B and C
Answer: D) Both B and C
39. Which device is used to convert direct current (DC) to alternating current (AC)?
A) Rectifier
B) Inverter
C) Transformer
D) Inductor
Answer: B) Inverter
40. The principle of electromagnetic induction was discovered by:
A) Thomas Edison
B) Nikola Tesla
C) Michael Faraday
D) Albert Einstein
Answer: C) Michael Faraday
41. Which of the following is a common application of a transformer?
A) In electric motors
B) In battery chargers
C) In power distribution systems
D) In resistors
Answer: C) In power distribution systems
42. The unit of capacitance is:
A) Farad
B) Henry
C) Ohm
D) Watt
Answer: A) Farad
43. The main function of an oscilloscope is to:
A) Measure resistance
B) Visualize electrical signals
C) Amplify signals
D) Convert signals
Answer: B) Visualize electrical signals
44. In an RLC circuit, the term “R” stands for:
A) Reactive
B) Resistance
C) Radiant
D) Relay
Answer: B) Resistance
45. Which type of circuit connection is characterized by a single path for current flow?
A) Parallel connection
B) Series connection
C) Complex connection
D) None of the above
Answer: B) Series connection
46. What happens to the total current in a series circuit when additional resistors are added?
A) It increases
B) It decreases
C) It remains the same
D) It fluctuates
Answer: B) It decreases
47. The SI unit of power is:
A) Joule
B) Watt
C) Volt
D) Ampere
Answer: B) Watt
48. Which of the following devices can convert light energy into electrical energy?
A) Solar cell
B) Battery
C) Generator
D) Capacitor
Answer: A) Solar cell
49. The term “grounding” refers to:
A) Connecting electrical circuits to the earth
B) Measuring resistance
C) Storing electrical energy
D) Regulating voltage
Answer: A) Connecting electrical circuits to the earth
50. A circuit that contains a voltage source and a load is called a:
A) Closed circuit
B) Open circuit
C) Series circuit
D) Parallel circuit
Answer: A) Closed circuit
51. The main purpose of a voltage regulator is to:
A) Increase current
B) Maintain a constant voltage
C) Convert AC to DC
D) Store energy
Answer: B) Maintain a constant voltage
52. Which of the following describes an inductive load?
A) Consumes energy in the form of heat
B) Stores energy in a magnetic field
C) Converts electrical energy into light
D) None of the above
Answer: B) Stores energy in a magnetic field
53. The primary function of a voltage divider is to:
A) Increase voltage
B) Decrease voltage
C) Measure resistance
D) Switch circuits
Answer: B) Decrease voltage
54. A synchronous motor operates at:
A) Variable speed
B) Constant speed
C) High torque
D) Low power factor
Answer: B) Constant speed
55. The main characteristic of a resistive load is that:
A) It does not store energy
B) It consumes energy in the form of magnetic fields
C) It causes phase shifts in current
D) None of the above
Answer: A) It does not store energy
56. In a circuit, the term “short circuit” refers to:
A) A high-resistance path
B) A low-resistance path
C) An open circuit
D) A complete circuit
Answer: B) A low-resistance path
57. The main advantage of using three-phase power systems is:
A) Higher efficiency
B) Simplicity in design
C) Lower cost
D) Increased safety
Answer: A) Higher efficiency
58. What type of signal does an alternating current produce?
A) Constant
B) Varying
C) Digital
D) None of the above
Answer: B) Varying
59. The output of a DC generator is:
A) Alternating current
B) Pulsating direct current
C) Constant direct current
D) None of the above
Answer: C) Constant direct current
60. A light bulb is an example of a:
A) Capacitive load
B) Resistive load
C) Inductive load
D) Reactive load
Answer: B) Resistive load
61. The formula for calculating electrical energy (E) consumed is:
A) E = P x T
B) E = P / T
C) E = P + T
D) E = P – T
Answer: A) E = P x T
62. In a series circuit, if one component fails, the entire circuit:
A) Continues to function
B) Stops functioning
C) Becomes more efficient
D) None of the above
Answer: B) Stops functioning
63. Which of the following is an example of a renewable energy source?
A) Coal
B) Natural gas
C) Solar energy
D) Nuclear energy
Answer: C) Solar energy
64. The symbol for an inductor in a circuit diagram is:
A) A coil
B) A triangle
C) A rectangle
D) A circle
Answer: A) A coil
65. The efficiency of a transformer is typically:
A) 20-40%
B) 40-60%
C) 70-95%
D) 95-100%
Answer: C) 70-95%
66. The unit of magnetic flux is:
A) Weber
B) Tesla
C) Henry
D) Ampere
Answer: A) Weber
67. The main purpose of an isolation transformer is to:
A) Increase voltage
B) Isolate circuits for safety
C) Store energy
D) Convert AC to DC
Answer: B) Isolate circuits for safety
68. What is the main component of a photovoltaic cell?
A) Silicon
B) Copper
C) Aluminum
D) Silver
Answer: A) Silicon
69. Which electrical quantity is a measure of opposition to current flow?
A) Voltage
B) Power
C) Resistance
D) Capacitance
Answer: C) Resistance
70. The efficiency of an electrical system can be affected by:
A) Temperature
B) Load conditions
C) Design parameters
D) All of the above
Answer: D) All of the above
71. A capacitor can store electrical energy in the form of:
A) Electric field
B) Magnetic field
C) Thermal energy
D) Mechanical energy
Answer: A) Electric field
72. The term “short circuit” usually refers to:
A) A protective device
B) A failure in the circuit
C) A connection with very low resistance
D) An open circuit
Answer: C) A connection with very low resistance
73. The power consumed in a resistive circuit can be calculated using which formula?
A) P = V^2 / R
B) P = V / R
C) P = I^2 x R
D) Both A and C
Answer: D) Both A and C
74. The voltage rating of a capacitor indicates:
A) The maximum voltage it can handle
B) The average voltage it produces
C) The minimum voltage required
D) None of the above
Answer: A) The maximum voltage it can handle
75. In which type of circuit is the voltage the same across all components?
A) Series circuit
B) Parallel circuit
C) Mixed circuit
D) None of the above
Answer: B) Parallel circuit
76. A synchronous motor operates at a speed that is:
A) Below synchronous speed
B) Above synchronous speed
C) Equal to synchronous speed
D) Varies with load
Answer: C) Equal to synchronous speed
77. The most common type of transformer used for power distribution is:
A) Step-up transformer
B) Step-down transformer
C) Isolation transformer
D) Auto-transformer
Answer: B) Step-down transformer
78. What is the effect of increasing resistance in a circuit with a constant voltage source?
A) Current increases
B) Current decreases
C) Voltage decreases
D) Power increases
Answer: B) Current decreases
79. The main purpose of an electric switch is to:
A) Measure current
B) Store energy
C) Control the flow of electricity
D) Increase voltage
Answer: C) Control the flow of electricity
80. The overall efficiency of a power system can be expressed as:
A) Input power divided by output power
B) Output power divided by input power
C) Total power consumed
D) None of the above
Answer: B) Output power divided by input power
81. What is the national flower of Pakistan?
A) Jasmine
B) Rose
C) Sunflower
D) Marigold
Answer: A) Jasmine
82. The largest province of Pakistan by area is:
A) Punjab
B) Sindh
C) Khyber Pakhtunkhwa
D) Balochistan
Answer: D) Balochistan
83. In which year did Pakistan conduct its first nuclear test?
A) 1996
B) 1998
C) 2000
D) 2001
Answer: B) 1998
84. Which river is known as the lifeline of Pakistan?
A) Jhelum
B) Chenab
C) Indus
D) Ravi
Answer: C) Indus
85. The city of Lahore is famous for:
A) Its deserts
B) Its historical landmarks
C) Its beaches
D) Its mountains
Answer: B) Its historical landmarks
86. Who is known as the “Nightingale of Pakistan”?
A) Noor Jehan
B) Abida Parveen
C) Farida Khanum
D) Rahat Fateh Ali Khan
Answer: A) Noor Jehan
87. The total number of provinces in Pakistan is:
A) 3
B) 4
C) 5
D) 6
Answer: B) 4
88. Which country shares the longest border with Pakistan?
A) India
B) Afghanistan
C) Iran
D) China
Answer: A) India
89. The chemical formula for table salt is:
A) NaCl
B) KCl
C) CaCO3
D) H2O
Answer: A) NaCl
90. What is the freezing point of water in Celsius?
A) 0°C
B) 32°C
C) 100°C
D) -10°C
Answer: A) 0°C
91. In basic mathematics, what is 10 multiplied by 6?
A) 50
B) 60
C) 70
D) 80
Answer: B) 60
92. Which of the following is an antonym of “happy”?
A) Joyful
B) Cheerful
C) Sad
D) Elated
Answer: C) Sad
93. The capital of the United States is:
A) New York
B) Washington, D.C.
C) Los Angeles
D) Chicago
Answer: B) Washington, D.C.
94. Which of the following is a basic data type in programming?
A) Integer
B) String
C) Boolean
D) All of the above
Answer: D) All of the above
95. What is the output of the expression 3 + 2 * 4?
A) 11
B) 14
C) 8
D) 10
Answer: A) 11
96. The process of photosynthesis occurs in which part of the plant?
A) Roots
B) Stem
C) Leaves
D) Flowers
Answer: C) Leaves
97. The capital city of France is:
A) Rome
B) Berlin
C) Paris
D) Madrid
Answer: C) Paris
98. Which of the following is a renewable source of energy?
A) Coal
B) Natural Gas
C) Solar Energy
D) Nuclear Energy
Answer: C) Solar Energy
99. What is the main function of the CPU in a computer?
A) To store data
B) To process data
C) To display data
D) To input data
Answer: B) To process data
100. The formula for calculating the area of a rectangle is:
A) Length × Width
B) Length + Width
C) Length – Width
D) Length ÷ Width
Answer: A) Length × Width