Power Generation MCQs 2026

In a Rankine cycle the working fluid undergoes isentropic expansion in the turbine

1. A true ✓
2. B false ✓
3. C only in the boiler ✓
4. D only in the condenser ✓

The boiler in a thermal power plant converts chemical energy of fuel into thermal energy of steam

1. A false ✓
2. B true ✓
3. C converts mechanical to electrical energy ✓
4. D stores electrical energy ✓

Increasing condenser vacuum generally improves thermal plant efficiency

1. A true ✓
2. B false ✓
3. C always reduces efficiency ✓
4. D has no effect on efficiency ✓

The function of a condenser in a steam power plant is to reject heat and condense exhaust steam

1. A false ✓
2. B to superheat steam ✓
3. C to increase boiler pressure ✓
4. D true ✓

Overall thermal plant efficiency is typically highest for combined cycle gas turbine plants among conventional thermal options

1. A false ✓
2. B true ✓
3. C simple Rankine coal plants ✓
4. D open cycle gas turbines alone ✓

Reheat in a Rankine cycle is used to reduce moisture at the turbine exhaust and improve efficiency

1. A false ✓
2. B to eliminate the condenser ✓
3. C true ✓
4. D to reduce boiler size only ✓

Regeneration in a steam cycle uses extracted steam to preheat feedwater before the boiler

1. A false ✓
2. B to cool the condenser ✓
3. C true ✓
4. D to bypass the turbine ✓

The turbine in a thermal plant converts enthalpy drop of steam into mechanical shaft work

1. A true ✓
2. B false ✓
3. C converts electricity to heat ✓
4. D only pumps water ✓

Boiler efficiency is defined as energy absorbed by water-steam divided by energy supplied by fuel

1. A false ✓
2. B true ✓
3. C electrical output divided by fuel input ✓
4. D turbine output divided by steam flow ✓

A superheater raises steam temperature above saturation at constant pressure in the boiler

1. A false ✓
2. B reduces steam pressure ✓
3. C condenses steam ✓
4. D true ✓

Net plant heat rate is inversely related to plant efficiency

1. A false ✓
2. B directly proportional to efficiency ✓
3. C unrelated to efficiency ✓
4. D true ✓

An economizer preheats feedwater using flue gas heat before it enters the boiler drum

1. A false ✓
2. B cools flue gases to atmosphere directly ✓
3. C true ✓
4. D replaces the superheater ✓

Carnot efficiency sets the theoretical upper limit for any heat engine operating between two reservoirs

1. A false ✓
2. B true ✓
3. C only applies to hydro plants ✓
4. D equals actual Rankine efficiency ✓

A deaerator removes dissolved oxygen and non-condensable gases from boiler feedwater

1. A true ✓
2. B false ✓
3. C adds oxygen to feedwater ✓
4. D replaces the condenser ✓

The pressure ratio across the turbine stages determines the enthalpy drop available for work

1. A false ✓
2. B only condenser vacuum matters ✓
3. C true ✓
4. D is fixed by generator rating ✓

Hydraulic head in a hydro plant is the vertical height through which water falls to produce energy

1. A false ✓
2. B true ✓
3. C horizontal distance of penstock ✓
4. D generator terminal voltage ✓

A penstock is a pipe or conduit that conveys water from the reservoir to the turbine

1. A true ✓
2. B false ✓
3. C the spillway of a dam ✓
4. D the generator cooling circuit ✓

Francis turbines are commonly used for medium head hydro installations

1. A false ✓
2. B only ultra-high head ✓
3. C only very low head run-of-river ✓
4. D true ✓

Pelton turbines use impulse buckets and are suited to high head low flow sites

1. A false ✓
2. B true ✓
3. C low head high flow only ✓
4. D nuclear steam applications ✓

Kaplan turbines are propeller-type machines suited to low head high flow conditions

1. A false ✓
2. B only above 500 m head ✓
3. C true ✓
4. D exclusively for pumped storage ✓

Run-of-river hydro plants have limited storage and follow the natural inflow of the river

1. A true ✓
2. B false ✓
3. C always include multi-year storage ✓
4. D do not use turbines ✓

Storage hydro plants can shift energy production from wet season to dry season using reservoirs

1. A false ✓
2. B cannot regulate output ✓
3. C operate without any dam ✓
4. D true ✓

Hydro power output is proportional to head times flow times efficiency in simplified form

1. A true ✓
2. B false ✓
3. C only head squared ✓
4. D independent of flow ✓

The powerhouse in a hydro plant houses turbines, generators, and auxiliary equipment

1. A false ✓
2. B only the dam crest ✓
3. C true ✓
4. D transmission substation alone ✓

A surge tank dampens pressure transients in long penstocks during load changes

1. A false ✓
2. B true ✓
3. C increases water hammer severity ✓
4. D replaces the governor ✓

Specific speed helps select the appropriate hydro turbine type for a given head and flow

1. A false ✓
2. B only applies to steam turbines ✓
3. C is the same as electrical frequency ✓
4. D true ✓

Pumped storage hydro uses off-peak electricity to pump water to an upper reservoir for later generation

1. A false ✓
2. B only generates during pumping ✓
3. C cannot provide peaking ✓
4. D true ✓

Nuclear power generation relies on controlled nuclear fission of heavy fuel nuclei

1. A false ✓
2. B true ✓
3. C nuclear fusion in commercial reactors ✓
4. D chemical combustion ✓

In a PWR the primary coolant water is kept under high pressure to remain subcooled

1. A true ✓
2. B false ✓
3. C allowed to boil in the reactor core ✓
4. D not used for heat removal ✓

In a BWR water boils directly in the reactor vessel to produce steam for the turbine

1. A false ✓
2. B uses molten salt primary loop ✓
3. C true ✓
4. D has no turbine ✓

Control rods in a nuclear reactor absorb neutrons to regulate reactivity and power level

1. A true ✓
2. B false ✓
3. C increase neutron population when inserted ✓
4. D generate electricity directly ✓

The moderator in thermal reactors slows fast neutrons to improve fission probability in fuel

1. A false ✓
2. B true ✓
3. C speeds up all neutrons ✓
4. D replaces coolant entirely ✓

Nuclear fuel enrichment for commercial LWRs increases the fraction of fissile U-235

1. A false ✓
2. B removes all U-235 ✓
3. C true ✓
4. D only applies to fusion fuels ✓

Containment structures in nuclear plants limit release of radioactivity during accidents

1. A false ✓
2. B only aesthetic purpose ✓
3. C replace emergency cooling ✓
4. D true ✓

Decay heat after reactor shutdown must still be removed to prevent fuel damage

1. A true ✓
2. B false ✓
3. C ceases instantly on shutdown ✓
4. D is negligible always ✓

A daily load curve shows variation of power demand over a 24-hour period

1. A false ✓
2. B annual energy only ✓
3. C true ✓
4. D generator efficiency only ✓

Base load is the relatively constant minimum demand sustained over long periods

1. A false ✓
2. B true ✓
3. C shortest duration peak ✓
4. D only reactive power ✓

Peak load occurs at maximum demand and is typically served by peaking or flexible plants

1. A false ✓
2. B minimum night demand ✓
3. C only hydro base units ✓
4. D true ✓

Load factor equals average load divided by maximum load over a given period

1. A true ✓
2. B false ✓
3. C maximum divided by average ✓
4. D peak demand times hours ✓

Diversity factor is the ratio of sum of individual maximum demands to the maximum of the combined demand

1. A false ✓
2. B always less than one ✓
3. C true ✓
4. D same as load factor ✓

Must-run status may be assigned to hydel or renewable plants due to zero or low marginal fuel cost

1. A false ✓
2. B only to oldest coal units ✓
3. C true ✓
4. D never applies in merit order ✓

Automatic generation control adjusts generator output to restore frequency and scheduled interchange

1. A true ✓
2. B false ✓
3. C only manual dispatch ✓
4. D controls consumer voltage directly ✓

The national grid integrates generation from hydel thermal nuclear and renewable sources across DISCO areas

1. A false ✓
2. B true ✓
3. C isolated regional grids only ✓
4. D excludes NTDC operation ✓

Peaking hydro units can start quickly compared to large coal steam units

1. A true ✓
2. B false ✓
3. C slower than all thermal ✓
4. D cannot change output ✓

Cogeneration produces both electricity and useful heat from the same fuel input

1. A false ✓
2. B true ✓
3. C only heat no power ✓
4. D reduces overall efficiency always ✓

Reactive power support is necessary for voltage control and is not the same as real power MW

1. A false ✓
2. B measured in megawatts alone ✓
3. C true ✓
4. D only needed in DC systems ✓

A forced outage reduces available plant capacity unexpectedly due to equipment failure

1. A false ✓
2. B planned maintenance shutdown ✓
3. C increases reserve margin ✓
4. D true ✓

Plant factor or capacity factor equals actual energy output divided by maximum possible output at rated capacity

1. A false ✓
2. B fuel cost divided by energy ✓
3. C only for hydro plants ✓
4. D true ✓

An annual load duration curve arranges loads in descending order of magnitude over the year

1. A false ✓
2. B true ✓
3. C chronological hourly plot only ✓
4. D shows fuel prices ✓

Coincidence factor is the reciprocal of diversity factor in load calculations

1. A true ✓
2. B false ✓
3. C equals plant factor ✓
4. D always zero ✓

Load factor of the system helps determine total energy sales and generation requirements

1. A false ✓
2. B only affects transmission voltage ✓
3. C unrelated to dispatch ✓
4. D true ✓

Peak-to-valley ratio on a daily curve influences spinning reserve and peaking plant needs

1. A false ✓
2. B only affects power factor ✓
3. C true ✓
4. D eliminates need for reserves ✓

Demand factor is ratio of maximum demand of a group to connected load of that group

1. A false ✓
2. B true ✓
3. C average to maximum load ✓
4. D diversity factor synonym ✓

WAPDA historically played a central role in developing and operating major public hydel power in Pakistan

1. A true ✓
2. B false ✓
3. C only regulates IPPs ✓
4. D owns all NTDC assets privately ✓

NTDC is responsible for bulk electric power transmission across Pakistan

1. A false ✓
2. B retail billing to all consumers ✓
3. C true ✓
4. D fuel supply to thermal plants ✓

Tarbela Dam is among the largest hydel power sources in Pakistan on the Indus River

1. A false ✓
2. B true ✓
3. C located on Jhelum only ✓
4. D a thermal coal plant ✓

Mangla Dam on the Jhelum River contributes significant hydel generation for the national grid

1. A false ✓
2. B is a gas turbine plant ✓
3. C located in Sindh only ✓
4. D true ✓

Ghazi Barotha is a run-of-river hydel project on the Indus downstream of Tarbela

1. A false ✓
2. B true ✓
3. C a nuclear station ✓
4. D only a coal import terminal ✓

Hydel power historically forms a major share of Pakistan installed generation capacity

1. A true ✓
2. B false ✓
3. C negligible compared to nuclear only ✓
4. D entirely replaced by solar ✓

Independent Power Producers sell electricity to the grid often under power purchase agreements

1. A false ✓
2. B cannot connect to national grid ✓
3. C only distribute locally without NTDC ✓
4. D true ✓

NEECA promotes energy conservation and efficiency standards in Pakistan

1. A false ✓
2. B operates all transmission lines ✓
3. C true ✓
4. D enriches uranium fuel ✓

Grid code defines technical requirements for connecting generators and loads to the power system

1. A false ✓
2. B only sets residential tariff slabs ✓
3. C replaces merit order dispatch ✓
4. D true ✓

Merit order dispatch schedules generators from lowest to highest marginal cost until demand is met

1. A false ✓
2. B true ✓
3. C highest cost first ✓
4. D random order ✓

Spinning reserve is online capacity that can respond quickly to frequency drops or generator trips

1. A true ✓
2. B false ✓
3. C offline cold reserve only ✓
4. D same as annual maintenance ✓

Economic dispatch minimizes total generation cost subject to demand and network constraints

1. A false ✓
2. B maximizes fuel consumption ✓
3. C true ✓
4. D ignores transmission limits ✓

Frequency of 50 Hz on the Pakistan grid must be maintained by matching generation and load

1. A false ✓
2. B 60 Hz standard ✓
3. C independent of generation ✓
4. D true ✓

A cold reserve unit is not synchronized and requires startup time before contributing power

1. A false ✓
2. B already spinning at full load ✓
3. C true ✓
4. D cannot ever start ✓

Transmission losses in Pakistan are reduced by operating at higher voltage for the same MW transfer

1. A true ✓
2. B false ✓
3. C lower voltage always reduces losses ✓
4. D losses independent of voltage ✓

Distributed generation includes smaller plants connected at distribution voltage levels

1. A false ✓
2. B true ✓
3. C only 500 kV lines ✓
4. D excludes rooftop solar ✓

Power purchase agreements define tariff, capacity obligations, and dispatch rules for IPPs

1. A false ✓
2. B only environmental permits ✓
3. C replace grid code entirely ✓
4. D true ✓