Free Power Systems MCQs with Answers

• A. equal to diesel power station
• B. more than diesel power station
• C. less than diesel power station

Explanation: A steam station needs boilers, turbines, condensers, cooling equipment, coal-handling systems and often ash-handling plant.

• A. increase the performance of the condenser
• B. increase the efficiency of the plant
• C. increase efficiency of the turbine

Explanation: A binary vapour cycle uses two working fluids so that heat addition and rejection can better match the available temperature ranges.

• A. higher critical temperature and pressure
• B. higher saturation temperature than other fluids
• C. relatively low vapourisation pressure
• D. all above

Explanation: Mercury has a high critical temperature, high saturation temperature and relatively low vapour pressure, making it suitable as the topping…

• A. utilise heat of flue gases
• B. increase thermal efficiency
• C. improve condenser performance
• D. reduce loss of heat

Explanation: Reheating expands steam in stages and returns it to the boiler for reheating between stages, raising the average temperature of heat…

• A. exhaust gases
• B. heaters
• C. draining steam from the turbine
• D. all above

Explanation: Regenerative heating uses steam bled or drained from intermediate turbine stages to heat the feedwater in feed heaters.

• A. increases with number of feed heaters increasing
• B. decreases with number of feed heaters increasing
• C. remains same unaffected by number of feed heaters
• D. none of the above

Explanation: Adding feed heaters raises the average temperature at which heat is supplied, so the maximum efficiency gain increases as more heaters are…

• A. when steam is extracted from only one suitable point of steam turbine
• B. when steam is extracted from several places in different stages of steam turbine
• C. when steam is extracted only from the last stage of steam turbine
• D. when steam is extracted only from the first stage of steam turbine

Explanation: Several extraction points heat the feedwater in stages, matching the water temperature more closely to the turbine expansion temperatures.

• A. decreases with increase in Rankine cycle efficiency
• B. increases with increase in Rankine cycle efficiency
• C. is unaffected by increase in Rankine cycle efficiency
• D. none of the above

Explanation: As the basic Rankine cycle becomes more efficient, the optimum regenerative arrangement generally uses a larger fraction of extracted…

• A. is always greater than simple Rankine thermal efficiency
• B. is greater than simple Rankine cycle thermal efficiency only when steam is bled at particular pressure
• C. is same as simple Rankine cycle thermal efficiency
• D. is always less than simple Rankine cycle thermal efficiency

Explanation: Regeneration increases the mean temperature of heat addition and therefore raises thermal efficiency compared with the corresponding…

• A. change of internal energy between inlet and outlet
• B. change of enthaply between inlet and outlet
• C. change of entropy between inlet and outlet
• D. change of temperature between inlet and outlet

Explanation: For steady, adiabatic turbine flow with negligible changes in kinetic and potential energy, turbine specific work equals the enthalpy…

• A. improves in summer as compared to that in winter
• B. improves in winter as compared to that in summer
• C. is unaffected by climatic conditions
• D. none of the above

Explanation: Cooler winter conditions lower the condenser cooling-water temperature and improve the condenser vacuum.

• A. 15 to 20 per cent
• B. 35 to 45 per cent
• C. 70 to 80 per cent
• D. 90 to 95 per ceut

Explanation: A practical steam power plant loses efficiency through boiler, turbine, generator, condenser and pumping losses, so its overall Rankine…

• A. 700 W/m2
• B. 800 W/m2
• C. 1 kW/m2
• D. 2 kW/m2

Explanation: Solar irradiance at the Earth's surface on a clear sunny day is commonly approximated as 1 kW/m², although it varies with location, time…

• A. using focusing collector or heliostates
• B. using flat plate collectors
• C. using a solar pond
• D. any of the above system

Explanation: Solar thermal power can use concentrating collectors or heliostats, low-temperature flat-plate systems, and solar ponds to produce heat…

• A. mechanical
• B. chemical
• C. heat
• D. sound

Explanation: A fuel cell produces electricity through an electrochemical reaction, directly converting the chemical energy of a fuel and oxidant into…

• A. human waste
• B. wet cow dung
• C. wet livestock waste
• D. all above

Explanation: Biogas is formed by anaerobic decomposition of organic wastes, including human waste, wet cow dung, and other livestock waste.

• A. high CO content in flue gases at exit
• B. high CO2 content in flue gases at exit
• C. high temperature of flue gases
• D. the smoking exhaust from chimney

Explanation: Incomplete combustion leaves unburnt carbon compounds and produces excess carbon monoxide, so a high CO concentration in the flue gas is…

• A. 21%
• B. 23%
• C. 77%
• D. 79%

Explanation: Dry atmospheric air contains approximately 21% oxygen by volume, with most of the remainder being nitrogen.

• A. 18%
• B. 23%
• C. 77%
• D. 79%

Explanation: Oxygen makes up about 23% of atmospheric air by mass because oxygen is heavier than nitrogen. By volume, its proportion is about 21%.

• A. solar, wind and biomass
• B. fossil fuels, hydropower and nuclear energy
• C. wood, animal wastes and agriculture wastes
• D. none of the above

Explanation: Commercial energy sources are traded or supplied through organized energy systems, such as fossil fuels, hydropower, and nuclear energy.