All Free Electrical Engineering MCQs with Answers
Every Electrical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
3,143 questions · page 146 of 158
2901. Which of the following devices may be used to provide protection against lightening over voltages?
- A. Horn gaps
- B. Rod gaps
- C. Surge absorbers
- D. All of the above
Explanation: Horn gaps, rod gaps and surge absorbers all provide paths or attenuation for lightning surges, protecting insulation and equipment from…
Correct answer: All of the above2902. Which of the following component, in a steam power plant, needs maximum maintenance attention?
- A. Steam turbine
- B. Condenser
- C. Water treatment plant
- D. Boiler
Explanation: The boiler operates under high temperature and pressure and contains many tubes, valves and auxiliary systems, making inspection, cleaning…
Correct answer: Boiler- A. Diesel engine plant
- B. Gas turbine plant
- C. Nuclear power plant
- D. Pumped storage plant
Explanation: Nuclear plants have high capital cost, low operating cost and limited load-following ability, so they are most economical when run…
Correct answer: Nuclear power plant- A. Solar energy
- B. Geothermal power
- C. Wind power
- D. iMHD
Explanation: MHD power generation was largely experimental and lacked the established reliability of conventional sources, making it the least reliable…
Correct answer: iMHD- A. Sinking fund method
- B. Straight line method
- C. Diminishing value method
- D. Halsey's 50-50 formula
Explanation: Sinking-fund, straight-line and diminishing-value methods are recognized depreciation methods.
Correct answer: Halsey's 50-50 formula- A. 15 to 20 years
- B. 20 to 50 years
- C. 50 to 75 years
- D. 75 to 100 years
Explanation: Diesel generating sets experience substantial mechanical wear and generally have a shorter service life than steam or hydroelectric…
Correct answer: 15 to 20 years2907. Which of the following is not necessarily an advantage of interconnecting various power stations?
- A. Improved frequency of power supplied
- B. Reduction in total installed capacity
- C. Increased reliability
- D. Economy in operation of plants
Explanation: Interconnection commonly improves reliability, permits economy of operation and reduces the required total installed or reserve capacity.
Correct answer: Improved frequency of power supplied- A. Electric clock
- B. Mixer grinder
- C. Ceiling fan
- D. Room heater
Explanation: A room heater is essentially a resistive load, so its operation is practically independent of supply frequency, unlike clocks, fans and…
Correct answer: Room heater- A. remains unchanged
- B. decreases
- C. increases
- D. none of the above
Explanation: Interconnecting systems allows their individual maximum demands to occur at different times, so the combined maximum demand is relatively…
Correct answer: increases- A. 0.5 lagging
- B. 0.5 leading
- C. 0.95 lagging
- D. 0.95 leading
Explanation: A consumer generally operates most economically at a high power factor, commonly taken as about 0.95 lagging.
Correct answer: 0.95 lagging- A. High maintenance cost
- B. Continuous losses in motor
- C. Noise
- D. All of the above
Explanation: A synchronous condenser has rotating parts, so it requires more maintenance, produces continuous motor losses, and may create operating…
Correct answer: All of the above- A. at the receiving end
- B. at the sending end
- C. either A. or (b)
- D. none of the above
Explanation: Reactive-power compensation is most effective when installed near the receiving end or load, where it reduces the reactive current carried…
Correct answer: at the receiving end- A. Phase advancers
- B. Synchronous compensators
- C. Static capacitors
- D. Any of the above
Explanation: Phase advancers, synchronous compensators, and static capacitors all supply or reduce the reactive power demanded by inductive loads.
Correct answer: Any of the above- A. It should run at high speed
- B. It should produce high voltage
- C. It should be small in size
- D. It should be capable of starting quickly
Explanation: A peak-load plant operates for short periods and must respond rapidly when demand rises.
Correct answer: It should be capable of starting quickly- A. Nuclear power plant
- B. Steam turbine plant
- C. Pumped storage plant
- D. None of the above
Explanation: Pumped-storage plants store energy during off-peak periods and release it rapidly during demand peaks, making them particularly suited to…
Correct answer: Pumped storage plant- A. Thermal power plant
- B. Diesel power plant
- C. Nuclear power plant
- D. Hydro-electric power plant
Explanation: Diesel power plants use compact, modular generating units and can be installed comparatively quickly.
Correct answer: Diesel power plant- A. diesel power plants
- B. nuclear power plants
- C. hydro-electric power plants
- D. thermal power plants
Explanation: Large thermal plants commonly consume huge quantities of coal or other fuel, making fuel transport a major logistical problem.
Correct answer: thermal power plants- A. Diesel engine plant
- B. Nuclear power plant
- C. Gas turbine plant
- D. Pumped storage plant
Explanation: Nuclear plants have high capital cost, low running cost, and are best operated continuously, so they are normally assigned base load.
Correct answer: Nuclear power plant- A. firm power
- B. cold reserve
- C. hot reserve
- D. spinning reserve
Explanation: Spinning reserve is generating capacity already synchronized with and connected to the bus bars, so it can accept load immediately.
Correct answer: spinning reserve- A. positive
- B. negative
- C. zero
- D. any of the above
Explanation: Salvage value depends on the plant's remaining value and disposal cost: it may be positive, zero, or effectively negative when dismantling…
Correct answer: any of the above