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Haryana BSEH Senior Secondary NSQF Power study materials
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Haryana BSEH Senior Secondary NSQF Power practice questions

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Question 1Basics of Power Sector and Energy Sources

In the Indian power system, which agency is responsible for the integrated operation of the national grid and for frequency control?

  1. Central Power Research Institute (CPRI)
  2. National Load Despatch Centre (NLDC) Correct answer.
  3. Central Electricity Regulatory Commission (CERC)
  4. Bureau of Energy Efficiency (BEE)

Explanation

Grid operation and frequency control are operational functions, and at national level these are handled by the National Load Despatch Centre, which coordinates the regional load despatch centres. Regulators such as CERC frame tariffs and rules rather than run the grid, so operational responsibility sits with the despatch centres.

Question 2Basics of Power Sector and Energy Sources

A thermal power plant burns coal to heat water into steam that drives a turbine coupled to a generator. In this chain, the turbine performs which function?

  1. It steps up the generator voltage for transmission.
  2. It condenses exhaust steam back into water.
  3. It converts the thermal energy of steam into mechanical energy. Correct answer.
  4. It converts the chemical energy of coal directly into electrical energy.

Explanation

The turbine is the mechanical link in the chain: steam expands across its blades and its thermal energy becomes rotational mechanical energy on the shaft. The generator then converts that mechanical energy into electrical energy, while the condenser handles steam recovery.

Question 3Basics of Power Sector and Energy Sources

Which energy source is classified as a renewable resource because it is replenished by natural processes on a human timescale?

  1. Wind Correct answer.
  2. Lignite
  3. Nuclear fuel
  4. Natural gas

Explanation

Wind is continuously regenerated by solar heating of the atmosphere, so it counts as renewable. Fossil fuels such as lignite and natural gas are finite, and nuclear fuel is a mined mineral resource that is consumed, not replenished.

Question 4Basics of Power Sector and Energy Sources

Why is electricity transmitted at high voltage over long distances in the Haryana state grid?

  1. Because high voltage raises the power factor of the load to unity.
  2. Because high voltage eliminates the need for transformers at substations.
  3. Because higher voltage reduces the current for the same power, lowering I²R line losses. Correct answer.
  4. Because higher voltage increases the current, which improves conductor cooling.

Explanation

For a given power transfer, raising the voltage reduces the current proportionally, and since line loss depends on the square of current, resistive losses fall sharply. This is why transmission is carried out at high voltage and then stepped down for distribution.

Question 5Basics of Power Sector and Energy Sources

In a hydropower station, the purpose of the penstock is to:

  1. house the generator and the step-up transformer
  2. release surplus water safely during floods
  3. store water so that generation can continue during dry periods
  4. carry water under pressure from the reservoir to the turbine Correct answer.

Explanation

The penstock is the closed conduit that conveys water from the intake at the dam down to the turbine, converting the head into a high-velocity jet or pressure flow. Storage is the reservoir's role and flood release is handled by spillways.

Question 6Basics of Power Sector and Energy Sources

A consumer's electricity bill in Haryana shows energy consumed in kWh. Which physical quantity does the kilowatt-hour measure?

  1. Power, the rate of energy use
  2. Electrical energy consumed over time Correct answer.
  3. The maximum demand in kVA
  4. The reactive power supplied to the load

Explanation

A kilowatt-hour is one kilowatt of power sustained for one hour, so it is a unit of energy, not of power. Utilities bill energy consumption in kWh while maximum demand and reactive power are recorded separately.

Question 7Basics of Power Sector and Energy Sources

Which type of power plant typically has the shortest start-up time from cold to full load, making it suitable for meeting sudden peaks?

  1. Large hydro reservoir plant
  2. Nuclear plant
  3. Coal-fired thermal plant
  4. Diesel generator set Correct answer.

Explanation

Diesel generator sets can be brought to full load within minutes, which makes them useful for peaking and emergency standby despite their high fuel cost. Coal and nuclear plants need long warming and synchronisation periods.

Question 8Basics of Power Sector and Energy Sources

In the context of the Indian power sector, what does the term 'distribution' refer to?

  1. Delivering power from substations to individual consumers at lower voltages Correct answer.
  2. Trading electricity on power exchanges
  3. Generating electricity from renewable sources
  4. Carrying bulk power at 400 kV between states

Explanation

Distribution is the final stage of the supply chain, taking power from distribution substations and delivering it to homes, farms and industries at low and medium voltages. Bulk high-voltage transfer between regions is transmission.

Question 9Basics of Power Sector and Energy Sources

A generating station supplies 50 MW for 8 hours each day. What energy does it deliver in one day?

  1. 4000 MWh
  2. 58 MWh
  3. 400 MWh Correct answer.
  4. 6.25 MWh

Explanation

Energy is power multiplied by time: 50 MW × 8 h = 400 MWh. Multiplying the two given values directly gives the daily energy, and no unit conversion is needed because both are in MW and hours.

Question 10Basics of Power Sector and Energy Sources

Why is a nuclear power plant normally operated as a base-load station rather than a peaking station?

  1. Its fuel cost per kWh is the highest of all plant types.
  2. It cannot be synchronised with the grid at all.
  3. It has high fixed capital cost and low fuel cost, so steady high output keeps average cost low. Correct answer.
  4. Its output cannot be varied under any circumstances.

Explanation

Nuclear plants carry heavy capital and low fuel costs, so running them at a steady high load factor spreads the capital charge over more units of energy. Frequent cycling also stresses the plant, which is an additional reason to keep output steady.

Question 11Basics of Power Sector and Energy Sources

In a solar photovoltaic plant, the inverter performs which essential function?

  1. It stores surplus energy as chemical energy.
  2. It converts the DC output of the modules into AC for the grid. Correct answer.
  3. It tracks the sun to maximise the angle of incidence.
  4. It concentrates sunlight onto the module surface.

Explanation

PV modules produce direct current, while the grid and most loads require alternating current, so the inverter performs the DC-to-AC conversion and also handles grid synchronisation. Storage and sun tracking are separate subsystems.

Question 12Basics of Power Sector and Energy Sources

A load of 100 kW operates at a power factor of 0.8 lagging. What is the apparent power drawn by the load?

  1. 20 kVA
  2. 80 kVA
  3. 125 kVA Correct answer.
  4. 180 kVA

Explanation

Apparent power equals real power divided by power factor: 100 kW ÷ 0.8 = 125 kVA. The apparent power is always larger than the real power when the power factor is below unity.

Question 13Basics of Power Sector and Energy Sources

Why does a wind turbine's power output vary with the cube of wind speed?

  1. Because blade pitch is fixed at all speeds.
  2. Because generator efficiency rises linearly with wind speed.
  3. Because the tower height increases with wind speed.
  4. Because the kinetic energy of moving air depends on the square of speed and the mass flow also rises with speed. Correct answer.

Explanation

Available wind power depends on the mass of air passing per second, which rises linearly with speed, and on the kinetic energy per unit mass, which rises with the square of speed. The product gives the cubic relationship, which is why site wind speed is so important.

Question 14Basics of Power Sector and Energy Sources

Which statement correctly distinguishes a captive power plant from a utility power plant?

  1. A captive plant is set up by an industrial consumer mainly to supply its own plant load. Correct answer.
  2. A captive plant must always use renewable fuel.
  3. A captive plant sells all its output to the state distribution licensee.
  4. A captive plant cannot be connected to the grid in any way.

Explanation

A captive generating plant is established primarily to serve the owner's own consumption, typically an energy-intensive industry, and surplus may be sold under rules. Utility plants, by contrast, generate mainly for sale to consumers.

Question 15Basics of Power Sector and Energy Sources

In an alternating current system, why is frequency kept close to 50 Hz in India?

  1. Because generators can only be built for 50 Hz.
  2. Because connected equipment is designed for that frequency and deviation stresses motors and transformers. Correct answer.
  3. Because 50 Hz is the only frequency permitted by physics for transmission.
  4. Because frequency determines the voltage level of the grid.

Explanation

Frequency is a system-wide indicator of the balance between generation and demand, and equipment such as motors, transformers and protection relays is designed for the nominal frequency. Large deviations cause overheating, vibration and protection maloperation, so the grid is kept near 50 Hz.

Question 16Basics of Power Sector and Energy Sources

A biomass power plant based on agricultural residue offers which environmental advantage over a coal plant of the same capacity?

  1. It releases no carbon dioxide at all during combustion.
  2. It requires no fuel handling or storage arrangements.
  3. It produces no ash of any kind.
  4. The carbon released was recently absorbed by the plants, so the net carbon addition is low. Correct answer.

Explanation

Burning biomass returns carbon that the plants took up while growing, so the net addition to the atmosphere is small when the residue is sustainably harvested. Coal, by contrast, releases carbon stored underground for millions of years.

Question 17Basics of Power Sector and Energy Sources

What is the main purpose of a substation in the power system?

  1. To consume reactive power from the transmission line.
  2. To convert mechanical energy into electrical energy.
  3. To change voltage levels and provide switching, protection and control functions. Correct answer.
  4. To store electrical energy for use during peak hours.

Explanation

Substations contain transformers for stepping voltage up or down along with switchgear, protection relays and control equipment that allow circuits to be switched and faults to be isolated. They are nodes in the network rather than sources or stores of energy.

Question 18Basics of Power Sector and Energy Sources

Why is a combined cycle power plant more efficient than a simple open-cycle gas turbine plant?

  1. It burns fuel at a higher flame temperature than any other plant.
  2. It avoids the use of any turbine at all.
  3. It operates only during off-peak hours when demand is low.
  4. It uses the hot exhaust gas from the gas turbine to raise steam and drive a second turbine. Correct answer.

Explanation

In a combined cycle plant the gas turbine exhaust, which would otherwise be wasted, passes through a heat recovery steam generator to produce steam for a steam turbine. Recovering this waste heat raises overall efficiency well above that of an open-cycle gas turbine.

Question 19Basics of Power Sector and Energy Sources

A 1 MW solar plant operates for an average of 5 equivalent sun hours per day. What is its approximate daily energy generation?

  1. 5 MWh Correct answer.
  2. 20 MWh
  3. 0.2 MWh
  4. 1 MWh

Explanation

Daily energy equals capacity multiplied by equivalent sun hours: 1 MW × 5 h = 5 MWh. Equivalent sun hours already fold the variation of irradiance across the day into a single figure.

Question 20Basics of Power Sector and Energy Sources

Which factor most directly explains why thermal power plants in India are often located near coal fields rather than near load centres?

  1. Coal loses its calorific value when transported.
  2. Thermal plants cannot be connected to long transmission lines.
  3. Load centres do not require electricity from thermal plants.
  4. Coal is bulky and costly to transport, so generation is sited close to the fuel source. Correct answer.

Explanation

Transporting large volumes of coal is expensive and logistically demanding, so pithead stations are built near mines and the electricity is carried by transmission lines instead. Transmission of power over hundreds of kilometres is generally cheaper than moving equivalent coal.

Question 21Basics of Power Sector and Energy Sources

In Haryana, a farmer uses a grid-connected electric pump set. Which characteristic of such a load affects the state's power system most directly?

  1. It draws power largely at night, contributing to an off-peak agricultural load profile. Correct answer.
  2. It improves the power factor of the feeder to near unity.
  3. It draws power mainly during daytime hours when solar generation is high.
  4. It reduces the maximum demand of the distribution feeder.

Explanation

Agricultural pump sets in many states, including Haryana, are commonly energised during night hours under rotational supply schedules, which shapes the state's load curve. Their induction motors also draw reactive power, so they tend to worsen rather than improve power factor.

Question 22Basics of Power Sector and Energy Sources

A transmission line delivers 100 MW at 220 kV with a line resistance causing 1% power loss. If the same power were delivered at 110 kV over the same conductor, the resistive loss would approximately be:

  1. 0.5%
  2. 4% Correct answer.
  3. 1%
  4. 2%

Explanation

Halving the voltage doubles the current for the same power, and since loss varies with the square of current, the loss becomes four times larger. A 1% loss therefore becomes about 4%.

Question 23Basics of Power Sector and Energy Sources

A state grid experiences a sudden loss of 800 MW of generation while demand stays unchanged. What is the immediate effect and the correct primary response?

  1. Frequency falls, and spinning reserve must be dispatched while load shedding may be triggered. Correct answer.
  2. Frequency remains constant because energy storage absorbs the deficit automatically.
  3. Frequency rises, and generation must be reduced further.
  4. Voltage rises, and capacitor banks must be switched in.

Explanation

When generation falls short of demand, the deficit is initially met from the kinetic energy of rotating machines, so system frequency drops. The remedy is to release spinning reserve and, if the fall is severe, shed load to arrest the decline.

Question 24Basics of Power Sector and Energy Sources

Why is the efficiency of a solar PV module lower than the theoretical maximum, even under standard test conditions?

  1. Because photons with energy below the band gap are not absorbed usefully, and excess photon energy is lost as heat. Correct answer.
  2. Because the inverter consumes most of the DC power produced.
  3. Because silicon cannot absorb any visible light.
  4. Because the module voltage is always zero in sunlight.

Explanation

A single-junction cell responds only to photons above its band-gap energy, and photons with excess energy lose the surplus as heat as they excite carriers. These spectral and thermalisation losses, along with recombination, keep practical efficiency well below the theoretical limit.

Question 25Basics of Power Sector and Energy Sources

Two plants serve the same annual energy demand: Plant A has a high fixed cost and low variable cost, Plant B has a low fixed cost and high variable cost. Which loading order minimises total system cost?

  1. Run Plant A first as base load and Plant B only for peaks. Correct answer.
  2. Run Plant B continuously and keep Plant A idle.
  3. Run both plants at exactly half load throughout the year.
  4. Run Plant B first because its fixed cost is low.

Explanation

Economic dispatch loads the unit with the lower variable (fuel) cost first, so Plant A should carry base load and Plant B should supply peaks. The high fixed cost of Plant A is recovered through a high load factor rather than through priority in the loading order.

Question 26Basics of Power Sector and Energy Sources

In the Indian power system, which segment of the value chain is responsible for stepping up voltage for long-distance transport and maintaining the regional grid's stability?

  1. Regulation
  2. Distribution
  3. Transmission Correct answer.
  4. Generation

Explanation

Transmission is the segment that carries bulk power at high voltage from generating stations to load centres and interconnects states through the regional and national grid. It is distinguished from distribution, which delivers power at lower voltage to end consumers. Maintaining grid frequency and voltage stability at the bulk level is a transmission system operator function.

Question 27Basics of Power Sector and Energy Sources

Which energy source is classified as a conventional, non-renewable source in India's power sector planning?

  1. Solar photovoltaic
  2. Small hydro
  3. Wind
  4. Coal Correct answer.

Explanation

Coal is a fossil fuel formed over geological time and is treated as a conventional, non-renewable resource in Indian generation planning. Solar, wind and small hydro are grouped as renewable sources because they are naturally replenished. Coal still supplies the largest share of India's electricity generation.

Question 28Basics of Power Sector and Energy Sources

A thermal plant burns coal with a calorific value of 4,000 kcal per kg and consumes 0.6 kg of coal per kWh generated. What is the approximate plant heat rate in kcal per kWh?

  1. 6,667 kcal/kWh
  2. 2,400 kcal/kWh Correct answer.
  3. 1,600 kcal/kWh
  4. 4,000 kcal/kWh

Explanation

Heat rate is the fuel energy consumed per unit of electricity generated, found by multiplying coal consumption per kWh by the coal's calorific value. Here 0.6 kg/kWh times 4,000 kcal/kg gives 2,400 kcal/kWh. This corresponds to an overall efficiency of roughly 860 divided by 2,400, about 36 percent.

Question 29Basics of Power Sector and Energy Sources

Two identical 100 MW units are committed to serve a load that peaks at 120 MW. Which operational consequence follows from this commitment decision?

  1. One unit carries the full load while the other stays at zero output
  2. The committed capacity exceeds demand, so part-load operation lowers efficiency and raises cost per unit Correct answer.
  3. The system frequency rises permanently above 50 Hz
  4. Both units run at full load with reserve margin intact

Explanation

Committing 200 MW of capacity against a 120 MW peak leaves 80 MW of unused capacity, so units must operate at part load. Thermal units are most efficient near full load, so part-load running increases heat rate and cost per kWh. Frequency is regulated by matching generation to demand continuously, not by the mere act of committing extra capacity.

Question 30Basics of Power Sector and Energy Sources

A state's peak demand is growing and its load curve has a sharp evening peak. Which portfolio decision best reduces the need for peaking capacity while keeping supply reliable?

  1. Operating existing thermal units at part load throughout the day
  2. Adding base-load coal capacity sized to the evening peak
  3. Reducing transmission capacity to lower capital expenditure
  4. Shifting flexible demand and using fast-start gas or pumped storage to cover the evening peak Correct answer.

Explanation

A sharp evening peak is best met by resources that can respond quickly, such as fast-start gas turbines and pumped storage, combined with demand-side shifting that moves consumption away from the peak. This reduces the capacity needed solely for a few peak hours. Sizing base-load coal to the peak would leave expensive capacity idle for most of the day.

Question 31Power Generation: Conventional and Renewable

In a coal-fired thermal power plant, which component converts the thermal energy of high-pressure steam into mechanical shaft work?

  1. The boiler furnace
  2. The economiser
  3. The condenser
  4. The steam turbine Correct answer.

Explanation

The steam turbine expands high-pressure, high-temperature steam through its blades, converting enthalpy of the steam into rotational mechanical energy that drives the generator. The boiler only raises steam, the condenser rejects heat, and the economiser preheats feedwater.

Question 32Power Generation: Conventional and Renewable

A hydroelectric station has a gross head of 50 m and a discharge of 20 m³/s. Taking water density as 1000 kg/m³ and g as 9.81 m/s², the theoretical power available in the water is closest to:

  1. 4.90 MW
  2. 19.6 MW
  3. 9.81 MW Correct answer.
  4. 0.98 MW

Explanation

Hydraulic power equals density × g × head × discharge, i.e. 1000 × 9.81 × 50 × 20 ≈ 9.81 × 10⁶ W, or about 9.81 MW. This is the ideal power before turbine and generator efficiencies are applied.

Question 33Power Generation: Conventional and Renewable

Which solar photovoltaic technology uses a thin film of cadmium telluride as the absorbing semiconductor layer?

  1. Polycrystalline silicon modules
  2. Monocrystalline silicon modules
  3. Concentrated solar thermal collectors
  4. CdTe thin-film modules Correct answer.

Explanation

CdTe modules use cadmium telluride as the light-absorbing layer deposited as a thin film, making them a leading commercial thin-film PV technology. Crystalline silicon modules use silicon wafers, and solar thermal collectors produce heat rather than electricity.

Question 34Power Generation: Conventional and Renewable

In a wind energy conversion system, the power available in the wind is proportional to which relationship with wind speed?

  1. The wind speed directly
  2. The square root of wind speed
  3. The square of wind speed
  4. The cube of wind speed Correct answer.

Explanation

Wind power equals one-half times air density times swept area times the cube of wind speed, so doubling wind speed raises available power about eightfold. This cubic dependence explains why site wind resource assessment is so important.

Question 35Power Generation: Conventional and Renewable

A diesel generator set coupled to an alternator is primarily used in power systems for which purpose?

  1. Base-load bulk generation
  2. Grid frequency regulation only
  3. Standby and captive power supply Correct answer.
  4. Transmission voltage transformation

Explanation

Diesel generating sets are compact and quick to start, so they serve as standby, emergency, and captive power sources rather than bulk base-load plants. They are not used for voltage transformation, which is the role of transformers.

Question 36Power Generation: Conventional and Renewable

Which nuclear reactor type uses heavy water as both moderator and coolant and can be refuelled while operating?

  1. Pressurised heavy water reactor Correct answer.
  2. Fast breeder reactor
  3. Boiling water reactor
  4. Pressurised water reactor

Explanation

The pressurised heavy water reactor uses heavy water (D₂O) as moderator and coolant, allowing the use of natural uranium fuel and on-power refuelling. Light water reactors use ordinary water, and fast breeders use a fast neutron spectrum without a moderator.

Question 37Power Generation: Conventional and Renewable

In a biomass gasifier, the partial oxidation of solid biomass produces a combustible gas mixture commonly called:

  1. Liquefied petroleum gas
  2. Natural gas
  3. Producer gas Correct answer.
  4. Water gas

Explanation

Gasification of biomass with a restricted air supply yields producer gas, a mixture containing carbon monoxide, hydrogen, methane, and nitrogen. Natural gas is mainly methane from geological sources, and LPG is a refined petroleum product.

Question 38Power Generation: Conventional and Renewable

A geothermal power plant of the dry-steam type relies on which resource characteristic?

  1. Solar heating of shallow groundwater
  2. Molten rock pumped directly to the turbine
  3. Hot water flashed into steam at the surface
  4. Naturally occurring dry steam from the reservoir Correct answer.

Explanation

Dry-steam plants use reservoirs that yield steam directly, so the steam can be routed to the turbine without flashing or a heat exchanger. Flash plants use hot pressurised water, and solar heating is unrelated to geothermal resources.

Question 39Power Generation: Conventional and Renewable

For a three-phase synchronous generator to deliver power to an infinite bus, the rotor speed must correspond to which condition?

  1. A speed below synchronous speed to allow slip
  2. Synchronous speed set by the number of poles and grid frequency Correct answer.
  3. A speed determined only by the prime-mover fuel input
  4. Any speed above the rated value

Explanation

A synchronous machine locks to the grid frequency, so its rotor must run at synchronous speed given by 120f divided by the number of poles. Slip is a feature of induction machines, not synchronous generators.

Question 40Power Generation: Conventional and Renewable

A solar PV module has an open-circuit voltage of 40 V and a short-circuit current of 8 A, with a fill factor of 0.75. Its maximum power output is closest to:

  1. 120 W
  2. 240 W Correct answer.
  3. 480 W
  4. 320 W

Explanation

Maximum power equals open-circuit voltage times short-circuit current times fill factor, so 40 × 8 × 0.75 = 240 W. The fill factor accounts for the non-ideal shape of the current-voltage curve.

Question 41Power Generation: Conventional and Renewable

Which factor is the main reason offshore wind farms achieve higher capacity factors than onshore sites?

  1. Absence of any need for grid connection
  2. Stronger and steadier wind resource over the sea Correct answer.
  3. Lower installation and maintenance cost
  4. Use of photovoltaic hybrid modules

Explanation

Sea surfaces have low roughness, so winds are stronger, less turbulent, and more persistent, raising the capacity factor. Offshore installation and maintenance are actually more expensive, and grid connection is still required.

Question 42Power Generation: Conventional and Renewable

In a thermal power plant, the purpose of the superheater is to:

  1. Raise steam temperature above its saturation value at the same pressure Correct answer.
  2. Condense exhaust steam back to water
  3. Reduce steam pressure before it enters the turbine
  4. Remove ash particles from flue gas

Explanation

A superheater adds heat to saturated steam at constant pressure, raising its temperature above saturation so that moisture at the turbine exhaust is reduced and cycle efficiency improves. Condensation and ash removal belong to other plant sections.

Question 43Power Generation: Conventional and Renewable

A run-of-river hydroelectric scheme differs from a storage scheme mainly because it:

  1. Requires pumped storage between two reservoirs
  2. Generates electricity only from tidal movement
  3. Uses only the natural river flow with little or no storage Correct answer.
  4. Stores large volumes of water behind a high dam

Explanation

Run-of-river plants divert part of the river flow and generate according to available discharge, with minimal pondage. Storage plants impound water in large reservoirs to regulate seasonal flow, and pumped storage is a separate concept.

Question 44Power Generation: Conventional and Renewable

The function of the charge controller in a stand-alone solar PV system with a battery bank is to:

  1. Track the sun mechanically to increase irradiance
  2. Convert DC from the array into grid-synchronised AC
  3. Step up the array voltage for transmission
  4. Regulate battery charging and prevent overcharge or deep discharge Correct answer.

Explanation

A charge controller manages the charging profile and disconnects or limits current to protect the battery from overcharge and excessive discharge. Inversion, tracking, and voltage transformation are performed by other components.

Question 45Power Generation: Conventional and Renewable

In a combined cycle power plant, the exhaust heat from a gas turbine is used to:

  1. Compress incoming natural gas for the combustor
  2. Filter particulate matter from the fuel
  3. Generate steam for a steam turbine in a heat recovery boiler Correct answer.
  4. Cool the generator stator windings

Explanation

A heat recovery steam generator captures gas-turbine exhaust heat to raise steam that drives a second turbine, raising overall efficiency. Fuel compression, generator cooling, and filtration are separate functions.

Question 46Power Generation: Conventional and Renewable

Which statement correctly describes the aerodynamics of a horizontal-axis wind turbine rotor?

  1. The rotor extracts all kinetic energy of the wind
  2. Blade pitch has no effect on power output
  3. Drag forces on flat plates produce all the useful torque
  4. Lift forces on the aerofoil blades produce the driving torque Correct answer.

Explanation

Modern turbine blades are aerofoils; the airflow produces lift that generates torque about the hub. The Betz limit shows that only about 59 percent of wind kinetic energy can be extracted, and pitch control directly regulates power.

Question 47Power Generation: Conventional and Renewable

A generating unit has a rated capacity of 200 MW and operates at an average output of 120 MW over a month. Its capacity factor is:

  1. 80 percent
  2. 120 percent
  3. 60 percent Correct answer.
  4. 40 percent

Explanation

Capacity factor is average output divided by rated capacity, so 120 divided by 200 equals 0.60, or 60 percent. It measures how fully the plant's rated capability is used over the period.

Question 48Power Generation: Conventional and Renewable

In a coal-fired plant, the electrostatic precipitator is installed to:

  1. Increase the calorific value of the coal
  2. Preheat the combustion air
  3. Reduce the sulphur dioxide content of flue gas
  4. Capture fine fly-ash particles from the flue gas Correct answer.

Explanation

An electrostatic precipitator charges fly-ash particles and collects them on oppositely charged plates, cutting particulate emissions. Sulphur removal needs flue-gas desulphurisation, and air preheating uses a separate heat exchanger.

Question 49Power Generation: Conventional and Renewable

The Indian government's NSQF framework is relevant to power-sector training mainly because it:

  1. Sets electricity tariffs for generating stations
  2. Defines competency levels and qualification packs for vocational skills Correct answer.
  3. Regulates the purchase price of solar modules
  4. Approves environmental clearances for power plants

Explanation

The National Skills Qualifications Framework organises vocational qualifications by competency level and links training to recognised job roles. Tariff setting and environmental clearance are handled by regulators and authorities, not by the skills framework.

Question 50Power Generation: Conventional and Renewable

A solar water-heating system on a rooftop uses which principle to transfer heat from the collector to the storage tank?

  1. Thermosiphon circulation of heated fluid Correct answer.
  2. Compression of refrigerant by a gas turbine
  3. Photovoltaic conversion of sunlight into direct current
  4. Combustion of biomass in the collector

Explanation

In a thermosiphon system, water heated in the collector becomes less dense and rises into the tank while cooler water descends, giving natural circulation without a pump. Photovoltaic conversion produces electricity, not hot water.