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 149 of 158
- A. 10 to 15%
- B. 30 to 40%
- C. 50 to 60%
- D. 60 to 70%
Explanation: Domestic appliances are used intermittently and their combined maximum demand is much higher than their average demand, so domestic load…
Correct answer: 10 to 15%- A. 15 years
- B. 30 years
- C. 60 years
- D. 100 years
Explanation: Hydroelectric stations have very long service lives because their turbines, generators and civil structures are robust and can be…
Correct answer: 100 years- A. Direct stroke on line conductor
- B. Indirect stroke on conductor
- C. Direct stroke on tower top
- D. Direct stroke on ground wire
Explanation: A direct stroke to a line conductor injects the lightning current directly into the electrical circuit, producing severe overvoltages and…
Correct answer: Direct stroke on line conductor- A. Easily damaged by high voltage
- B. Cannot be repaired
- C. Short service life
- D. All of the above
Explanation: Static capacitors can be damaged by overvoltage, and an individual unit is normally replaced rather than repaired; their service life is…
Correct answer: All of the above- A. peak load plant
- B. casual run plant
- C. either A. or (b)
- D. base load plant
Explanation: Efficiency matters least for a peak-load or casual-run plant because it operates for relatively few hours.
Correct answer: either A. or (b)2966. The primary reason for low power factor is supply system is due to installation of____________?
- A. induction motors
- B. synchronous motors
- C. single phase motors
- D. d.c. motors
Explanation: Induction motors draw magnetising current and therefore consume substantial reactive power, causing a lagging power factor in supply…
Correct answer: induction motors- A. peak demand
- B. average demand
- C. diversified demand
- D. none of the above
Explanation: A load curve plots demand against time, so its highest ordinate is the maximum or peak demand reached during the period.
Correct answer: peak demand- A. peak load plants
- B. base load plants
- C. either A. or (b)
- D. none of the above
Explanation: Base-load plants operate for long periods, so their high capital cost is spread over many generated units and their superior efficiency…
Correct answer: base load plants- A. 25 to 50 percent full load
- B. 50 to 75 percent full load
- C. full load
- D. 25 percent overload
Explanation: Peak-load generators commonly achieve maximum efficiency below full load, typically around 50 to 75 percent of rated load.
Correct answer: 50 to 75 percent full load- A. Cost of wages
- B. Cost of fuel
- C. Cost of lubricants
- D. All of the above
Explanation: Running cost is incurred during operation, including wages for operating staff, fuel consumption, and lubricants.
Correct answer: All of the above- A. kW
- B. kWh
- C. kVAR
- D. none of the above
Explanation: A capacitor supplies reactive power, so its rating is expressed in kilovolt-amperes reactive, or kVAR.
Correct answer: kVAR- A. Nuclear
- B. Hydro
- C. Thermal
- D. Diesel
Explanation: A hydroelectric station has no fuel cost and comparatively low operating and maintenance expenses after construction.
Correct answer: Hydro- A. Peak load plant
- B. Base load plant
- C. Nuclear power plant
- D. Hydro electric plant
Explanation: A peak-load plant operates only when demand is high, so its average load remains below its maximum demand and its load factor cannot reach…
Correct answer: Peak load plant- A. fixed charges
- B. operating or running charges
- C. both A. and (b)
- D. either A. or (b)
Explanation: In a two-part tariff, fixed charges depend mainly on maximum demand, whereas running charges depend on energy consumed.
Correct answer: operating or running charges- A. Load survey method
- B. Mathematical method
- C. Statistical method
- D. Economic parameters
Explanation: Statistical methods estimate demand from previous consumption patterns, diversity, growth and seasonal variation.
Correct answer: Statistical method- A. Nuclear power plant
- B. Hydro power plant
- C. Steam power plant
- D. Diesel power plant
Explanation: Steam plants generally have the lowest overall efficiency among these conventional options because several heat-conversion and mechanical…
Correct answer: Steam power plant- A. thermodynamic cycle
- B. Rankin cycle
- C. Vapor pressure cycle
- D. Carton cycle
Explanation: Steam power stations operate on the Rankine cycle, in which water is pumped, heated into steam, expanded through a turbine, and then…
Correct answer: Rankin cycle- A. Thermal Power Plant
- B. Hydro Power Plant
- C. Nuclear Power Plant
- D. Diesel Power Plant
Explanation: Hydro plants produce electricity without burning fuel, so they have very low direct air pollution during operation.
Correct answer: Hydro Power Plant- A. Nuclear power plants
- B. Hydro-electric power plants
- C. Thermal power plants
- D. Diesel engine power plant
Explanation: Thermal plants usually require high maintenance because boilers, turbines, condensers, fuel-handling equipment, and pollution-control…
Correct answer: Thermal power plants- A. less than
- B. equal to
- C. greater than
- D. none of the above
Explanation: Overall efficiency equals thermal efficiency multiplied by the efficiencies of the boiler, turbine, generator, and other auxiliaries.
Correct answer: less than