Power Generation MCQ [Free PDF] – 13 Objective Questions with Answers

The boiler's primary function is to transfer heat from fuel/heat source to feedwater and convert the water into high-pressure steam for the turbine.

The condenser removes latent heat from turbine exhaust steam and converts it back into water (condensate), while maintaining a low exhaust pressure that improves turbine work output.

A cooling tower rejects waste heat from the condenser cooling-water circuit to the atmosphere, lowering the water temperature so it can be recirculated through the condenser.

A conventional steam power plant typically converts roughly 30–40% of fuel heat into electrical output, depending on steam conditions, reheat/regeneration and plant technology. The rest is rejected mainly in the condenser and stack.

Coal's chemical energy is released as heat in the boiler; steam carries that thermal energy to the turbine, where it becomes mechanical shaft energy; the generator converts the mechanical energy into electrical energy. Among the listed simplified chains, Heat → Mechanical → Electrical is correct.

Uranium is not a combustion fuel for a conventional steam power plant; it is nuclear fuel used in a reactor to produce heat through fission. Coal, natural gas and oil can all be burned in thermal/steam plants.

B — Electrical power output ÷ input potential energy of water. Hydel efficiency compares the useful electrical output with the water power ρgQH available.

Thermal nuclear reactors slow neutrons with a moderator so fission remains effective in thermal-fuel systems. Because capital cost is high and fuel cost comparatively low, nuclear plants are generally operated as base-load, not peak-only, units. Key relation: k_eff=1 critical; >1 supercritical; <1 subcritical.

Exam focus: Critical reactor means neutron population is steady. Common trap: Nuclear plants are not peak-load-only plants.

B — Control rods. Made of neutron absorbers such as boron or cadmium, they absorb excess neutrons to control the chain reaction or shut the reactor down.

B — Pelton turbine. It is an impulse turbine best suited to high head and low discharge; Francis suits medium head and Kaplan suits low head with high flow.

Pumped-storage hydro stores energy by pumping water to an upper reservoir during low-demand periods and generating during peaks. Its rapid start and reversible pump-turbine equipment make it valuable for peak support, balancing and reserves rather than as a conventional base-load plant. Key relation: Stored potential energy≈ρgH·volume.

Exam focus: Pumped storage shifts energy in time; it does not create net energy. Common trap: Do not classify it as a normal base-load plant.

Steam/coal power stations need large quantities of water for the steam cycle and cooling, take substantial time to construct, and involve significant fuel handling, ash disposal, operation and maintenance. These features make claims of very low O&M or easy coal/ash handling suspect. Key relation: Rankine-cycle efficiency depends on boiler/condenser/turbine conditions.

Exam focus: Remember water and fuel/ash handling as major thermal-plant auxiliaries. Common trap: Coal and ash handling is a plant burden, not an easy advantage.

A — Kaplan turbine. It is an axial-flow reaction turbine with adjustable blades, ideal for low-head, high-discharge sites.