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10 free 4A practice questions (printable)

Ten original exam-style 4th Class Part A (4A) questions from our free public sample, written to the public syllabus. Work them on paper, then check the answer key at the end. They are not questions from a real exam, and a score here does not predict your exam result.

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1. A body travels a distance of 1000 m in 65 seconds at a constant rate. What is its average velocity?

  • A. 15.4 m/s
  • B. 18.2 m/s
  • C. 65.0 m/s
  • D. 12.5 m/s

Question ID KE-A01-C01-Q001 · Unit A-1: Elementary Mechanics and Dynamics · Report an error

2. A chain drive uses a 300 mm diameter drive sprocket and a 1000 mm diameter driven sprocket. If the drive shaft turns at 890 rev/min, what is the rotational speed of the driven shaft?

  • A. 595 rev/min
  • B. 267 rev/min
  • C. 2967 rev/min
  • D. 445 rev/min

Question ID KE-A01-C09-Q005 · Unit A-1: Elementary Mechanics and Dynamics · Report an error

3. At room temperature (approximately 20°C) and atmospheric pressure, which of the following lists the phases of steam, nitrogen, copper, lemonade, and cast iron correctly?

  • A. Gas, liquid, solid, solid, solid
  • B. Gas, gas, solid, liquid, solid
  • C. Gas, gas, liquid, liquid, solid
  • D. Liquid, gas, solid, liquid, solid

Question ID KE-A02-C01-Q001 · Unit A-2: Elementary Physical, Chemical, and Thermodynamic Principles · Report an error

4. When ASME published CSD-1 in 1977, it focused on four specific safety hazards associated with the operation of smaller, automatically fired boilers. Which of the following correctly identifies all four of those hazards?

  • A. Low water, overpressure, over-temperature, and furnace explosion
  • B. Overpressure, flame failure, corrosion fatigue, and carbon monoxide poisoning
  • C. Low water, flue gas leakage, fuel contamination, and electrical failure
  • D. Over-temperature, water hammer, scale buildup, and furnace explosion

Question ID KE-A03-C03-Q008 · Unit A-3: Introduction to Power Engineering and Its Governance in Canada · Report an error

5. Chapter 1 of Unit A-5 examines four specific Biogeochemical Cycles in detail. Which option correctly lists all four?

  • A. Carbon, Nitrogen, Phosphorus, and Soil cycles
  • B. Oxygen, Water, Carbon, and Soil cycles
  • C. Oxygen, Carbon, Nitrogen, and Water cycles
  • D. Water, Carbon, Sulfur, and Oxygen cycles

Question ID KE-A05-C01-Q001 · Unit A-5: Introduction to Plant Operations and the Environment · Report an error

6. Which mechanical property describes a material's ability to return to its original dimensions once a deforming force is removed?

  • A. Malleability
  • B. Plasticity
  • C. Ductility
  • D. Elasticity

Question ID KE-A06-C01-Q001 · Unit A-6: Elements of Material Science and Welding Technology · Report an error

7. When a valve stem is leaking and the existing packing still has sufficient material, what is the correct first action?

  • A. Tighten the packing gland as firmly as possible to guarantee all leakage stops
  • B. Remove all packing from the stuffing box and install new packing rings
  • C. Shut the valve completely and leave it closed until the packing can be replaced during a planned outage
  • D. Slightly tighten the packing nut or gland, ensuring bolted glands are tightened evenly

Question ID KE-A07-C02-Q006 · Unit A-7: Introductory Fluid Handling Technology · Report an error

8. Which device is specifically designed to protect sensitive computer and control systems from even a momentary interruption of AC power?

  • A. A load-shedding relay that isolates non-critical circuits during an outage
  • B. An automatic transfer switch (ATS) with open transfer capability
  • C. A key-interlocked tie circuit breaker connected to a standby bus
  • D. An uninterruptible power supply (UPS) with battery backup and inverter

Question ID KE-A08-C06-Q021 · Unit A-8: Basic Concepts in Electrotechnology · Report an error

9. An open-loop control system is also referred to by which alternative name?

  • A. Adaptive control system
  • B. Feedback control system
  • C. Non-feedback control system
  • D. Proportional control system

Question ID KE-A09-C01-Q001 · Unit A-9: Energy Plant Instrumentation and Controls · Report an error

10. Which of the following correctly pairs a combustible element found in boiler fuels with the compound it forms during complete combustion with oxygen?

  • A. Hydrogen reacts with oxygen to form water vapour (H2O)
  • B. Carbon reacts with oxygen to form carbon monoxide (CO)
  • C. Sulfur reacts with oxygen to form sulfur trioxide (SO3)
  • D. Nitrogen reacts with oxygen to form nitrogen dioxide (NO2)

Question ID KE-A12-C01-Q001 · Unit A-12: Elements of Boiler Systems · Report an error

Answer key

  1. 1. A (KE-A01-C01-Q001), Average velocity equals displacement divided by time: 1000 m ÷ 65 s ≈ 15.38 m/s, which rounds to 15.4 m/s. The choice of 65.0 m/s is a common error in which the student reads the time value (65 s) directly as a speed without performing the division.
  2. 2. B (KE-A01-C09-Q005), Chain drive speed ratio follows the same inverse-diameter rule as gear drives: N_driven = N_driver × (D_driver / D_driven) = 890 × (300/1000) = 267 rev/min. The driven sprocket is larger, so it turns more slowly. Inverting the diameters gives approximately 2967 rev/min, which is the most common error.
  3. 3. B (KE-A02-C01-Q001), Steam is water in the gaseous phase; nitrogen (N2, boiling point −196°C) is a gas at room temperature; copper (a metal) and cast iron (an iron alloy) are both solids; lemonade is an aqueous liquid mixture. The correct sequence is gas, gas, solid, liquid, solid. Choices that list lemonade as a solid or nitrogen as a liquid are incorrect under standard room conditions.
  4. 4. A (KE-A03-C03-Q008), CSD-1 was published specifically to address four hazards related to the operation of smaller, automatically fired boilers: low water, overpressure, over-temperature, and furnace explosion. The other options include plausible but out-of-scope items such as flame failure, water hammer, and carbon monoxide. These are not among the four hazards explicitly named in the CSD-1 introduction.
  5. 5. B (KE-A05-C01-Q001), The four biogeochemical cycles covered in detail here are oxygen, water, carbon, and soil. Nitrogen and phosphorus are important recycled elements, but they are not part of that set of four. Sulfur is not one of the four either.
  6. 6. D (KE-A06-C01-Q001), Elasticity is specifically defined as the ability of a material to return to its original shape after a deforming force is removed. Plasticity is the opposite: plastic materials do not return to their original shape. Ductility refers to permanent deformation under tensile load, and malleability refers to permanent deformation under compressive load.
  7. 7. D (KE-A07-C02-Q006), The correct first action for a stem leak when sufficient packing remains is to slightly tighten the packing nut or gland; bolted glands must be tightened evenly to avoid binding the stem. Over-tightening causes extra friction and wear, so the gland should only be snugged enough to stop the leak. Replacing all packing is only necessary when insufficient packing remains. Leaving the valve shut without corrective action is not the recommended procedure.
  8. 8. D (KE-A08-C06-Q021), An uninterruptible power supply (UPS) provides continuous power to sensitive systems, such as computers, controls, and communication equipment, that cannot tolerate even a momentary loss of power. It combines a rectifier, battery bank, and inverter to deliver seamless power during outages. An ATS with open transfer would still introduce a brief interruption, making it unsuitable for systems that require zero downtime.
  9. 9. C (KE-A09-C01-Q001), An open loop is a non-feedback control system: it does not measure the result and send that measurement back. A closed loop is a feedback control system, because it uses a measurement of the process to adjust the output.
  10. 10. A (KE-A12-C01-Q001), The three combustible elements in boiler fuels are carbon, hydrogen, and sulfur. During complete combustion, hydrogen combines with oxygen to produce water vapour (H2O). Carbon forms carbon dioxide (CO2), not carbon monoxide, which is an incomplete combustion product. Sulfur forms sulfur dioxide (SO2), not sulfur trioxide. Nitrogen is not a combustible element and its presence in air is generally treated as non-reactive at normal combustion temperatures.

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