Electrical Power Generation MCQs – 1000+ Power Generation Objective Multiple Choice Questions and Answers

Electrical Power Generation MCQs let you test your knowledge of various conventional and non-conventional electric generation units. The multiple-choice questions are targetted on Hydroelectric, steam, coal, nuclear, gas, wind, solar, and other renewable as well as non-renewable sources of electrical power. Various MCQs on components, machines, devices, and structures let you evaluate your own knowledge before appearing in Entry tests, competitive exams, university, and college tests as well as for job interviews.

The primary source of energy in the universe is

The primary source of energy in the universe is:

1. Fuels
2. Wind
3. Water
4. Sun

Correct answer: 4. Sun

Explanation: The most important & primary source of energy is the sun. Sun is responsible for heating the earth’s surface and the Earth heats the air above it, thus resulting in the wind. Water evaporated by the sun forms clouds. The rain results in flowing streams and rivers that in turn provide hydropower.

The largest source of power generation at present

The largest source of power generation at present:

1. Coal
2. Nuclear
3. Water
4. Oil

Correct answer: 1. Coal

Explanation:

2019 world electricity generation by source (total generation was 27 PWh)

1. Coal (37%)
2. Natural gas (24%)
3. Hydro (16%)
4. Nuclear (10%)
5. Wind (5%)
6. Solar (3%)
7. Other (5%)

Source: https://www.iea.org/data-and-statistics/charts/world-gross-electricity-production-by-source-2019

Alternator converts ____________ to __________

Alternator converts ____________ to __________:

1. Mechanical, Electrical (AC)
2. Electrical (AC), Mechanical
3. Mechanical, Electrical (DC)
4. Electrical (DC), Mechanical

Correct answer: 1. Mechanical, Electrical (AC)

Explanation: A synchronous generator, also known as an alternator converts mechanical energy into electrical energy in the form of alternating current (AC). In power stations, mechanical energy is typically supplied to the generator by a turbine, which could be driven by various sources such as steam, water, or gas. As the turbine spins, it rotates the rotor of the synchronous generator. This rotation induces an alternating current in the stator windings through electromagnetic induction. The electrical energy produced by the generator is then transmitted through power lines to consumers.

In summary an alternator or synchronous generator converts mechanical energy (from the turbine) into electrical energy (in the form of AC).

Continue Reading: Synchronous generator MCQs.

The term pulverized features the fuel of

The term pulverized features the fuel of:

1. Gas power station
2. DAM
3. Steam power station
4. Wind turbine

Correct answer: Steam power station

Explanation: Pulverization also known as crushing or grinding is defined as the process of applying an external force to coal in order to reduce it into pieces that are smaller than the original size. Pulverization of coal is the favored method since it prepares the coal for burning purposes.

The mechanical pulverization of coal into a fine powder enables it to be burned like a gas, thus leading to its efficient combustion. The term pulverization features the fuel of a steam power station. In steam power station pulverization of coal is carried out before combustion.

Low heads employ

Low heads employ:

1. Impulse turbine
2. Francis turbine
3. Propeller turbine
4. Pelton turbine

Correct answer: 3. Propeller turbine

Explanation: Propeller turbine belongs to the class of reaction turbines. Such turbines are generally used for sites with lower head and higher flows. The propeller turbine generally has a runner with three to six blades.

Impulse turbines are generally suitable for high-head, low-flow applications. Francis turbines are usually recommended for medium- to high-head (130- to 2,000-foot) and their use for low heads is rare. Pelton turbine is actually a type of impulse turbine and is generally recommended for high head power plants.

Spillway belongs to which structure

Spillway belongs to which structure:

1. Hydroelectric power plant
2. Steam power station
3. Nuclear power station
4. Wind turbine

Correct answer: 1. Hydroelectric power plant

Explanation: Spillway belongs to the hydroelectric power plant and it is a structure constructed in a hydroelectric dam in order to provide a safe path for floodwaters to escape to some downstream area.

Read more EEMCQs here

The condenser in which there is no direct contact between steam and water

The condenser in which there is no direct contact between steam and cooling water:

1. Jet condenser
2. Surface condenser
3. Both of these
4. None of these

Correct answer: 2. Surface condenser

Explanation: A surface condenser is a heat exchanger that converts steam from gaseous to its liquid state at a pressure below atmospheric pressure. A surface condenser is a water-cooled shell and tube heat exchanger that is installed to condense exhaust steam from a steam turbine in thermal power stations.

In a jet condenser, the cooling water and steam are mixed up, however in a surface condenser steam and cooling water are not mixed up.

The analysis which provides the complete chemical analysis of coal

The analysis which provides the complete chemical analysis of coal:

1. Ultimate analysis
2. Proximate analysis
3. Breath analysis
4. Life cycle analysis

Correct answer: 1. Ultimate analysis

Explanation: The ultimate analysis of coal involves the determination of the weight percent of carbon as well as sulfur, nitrogen, and oxygen. Trace elements that occur in coal are typically included as a part of the ultimate analysis. The ultimate analysis of coal provides a convenient method for reporting the major organic elemental composition of coal.

Which of the following doesn’t belong to full admission turbine

Which of the following doesn’t belong to full admission turbine:

1. Propeller
2. Francis
3. Kaplan
4. Pelton

Correct answer: 4. Pelton

The direction of turbines is reversed in

The direction of turbines is reversed in:

1. Run-of-the-river plants
2. Pumped storage plants
3. Storage plants
4. None of these

Correct answer: 2. Pumped storage plants

Explanation: Pumped-storage power plants are reversible hydroelectric facilities wherein water is pumped uphill into a reservoir.

During times when there is very high electricity consumption on the grid, the water from the upper reservoir, carried downhill by a penstock, drives a turbine and a generator in order to generate electric power is used for meeting the increased demand.

However, when demand is low the electricity is taken from the grid to power a pump. The pump sends water from the lower reservoir back up to the upper reservoir. Once in the upper reservoir, water can be discharged again to drive the turbine. In this manner water in the upper reservoir constitutes a stock of gravitational potential energy that can be used when needed.

The turbines in the pumped storage plant could operate as both turbine-generators and in reverse as electric motor-driven pumps.

Watch the working of pumped storage plants in below video:

In a distribution system, in order to improve power factor, the synchronous capacitors are installed

In a distribution system, in order to improve power factor, the synchronous capacitors are installed

1. At the receiving end
2. At the sending end
3. Either of above
4. None of above

Correct answer: 1. At the receiving end

During load shedding

During load shedding

1. Some loads are switched off
2. System frequency is reduced
3. System power factor is changed
4. System voltage is reduced

Correct answer: 1. Some loads are switched off

Explanation: During load shedding, the primary objective is to maintain the balance between power generation and demand, especially during periods of high demand or unexpected system faults. Load shedding involves the controlled and temporary switching off of specific loads to prevent a complete blackout or system collapse. By shedding non-essential loads, the system can prioritize critical loads and maintain stability.

Also see: Electrical Engineering XYZ article on What is Load Shedding and Why it Happens

The essential requirement of peak load plant is that

The essential requirement of peak load plant is that

1. It should be capable of starting quickly
2. It should be small in size
3. It should produce high voltage
4. It should run at high speed

Correct answer: 1. It should be capable of starting quickly

Explanation: Peak load plants are power plants that are primarily designed to meet the electricity demand during periods of peak consumption, such as hot summer days when air conditioners are running at maximum capacity. Therefore, the essential requirement of a peak load plant is to be able to start up quickly to provide additional power to meet the increased demand.

An over excited synchronous motor on no-load is termed as

An over excited synchronous motor on no-load is termed as

1. Alternator
2. Generator
3. Induction motor
4. Synchronous condenser

Correct answer: 4. Synchronous condenser

Explanation: When a synchronous motor is over-excited and operates on no-load, it effectively acts as a synchronous condenser. This machine absorbs reactive power and is used primarily to adjust the power factor of the electrical system. It helps stabilize voltage and enhances the efficiency of power transmission.

The area under a load curve gives

The area under a load curve gives

1. Average demand
2. Energy consumed
3. Maximum demand
4. None of these

Correct answer: 2. Energy consumed

Learn Daily vs Monthly vs Yearly Load Curves here

Which of following will be least affected due to charge in supply voltage frequency

Which of following will be least affected due to charge in supply voltage frequency

1. Ceiling fan
2. Electric clock
3. Mixer grinder
4. Room heater

Correct answer: 4. Room heater

The power plant that is invariably used as base load plant

The power plant that is invariably used as base load plant

1. Diesel engine plant
2. Gas turbine plant
3. Nuclear power plant
4. Pumped storage plant

Correct answer: 3. Nuclear power plant

Explanation: Nuclear power plants are most suitable for base load operation because they are capable of producing large amounts of continuous, reliable electricity at a relatively low marginal cost once constructed. Nuclear plants, however, have high upfront capital costs and long ramp-up times, making them inefficient for load-following (adjusting output as demand varies throughout the day). Once operational, their economic efficiency is maximized by running them continuously at high capacity. This makes them ideal as base load plants, which require consistent, uninterrupted output.

Which of the below mentioned is the disadvantage of static capacitor for power factor improvement

Which of the below mentioned is the disadvantage of static capacitor for power factor improvement

1. Cannot be repaired
2. Easily damaged by high voltage
3. Short service life
4. All of the above

Correct answer: 4. All of the above

Explanation: Each listed disadvantage pertains to static capacitors used in power factor improvement:

1. Cannot be repaired – Static capacitors typically require replacement rather than repair upon failure.
2. Easily damaged by high voltage – Capacitors can be damaged by voltage spikes exceeding their rated capacity.
3. Short service life – In harsh or demanding environments, capacitors may face a shortened lifespan due to frequent stress.

For high value of diversity factor, a power station

For high value of diversity factor, a power station of given installed capacity will be in a position to supply

1. Less number of consumers
2. More number of consumers
3. Neither of above
4. Either of above

Correct answer: 2. More number of consumers

Explanation: A high diversity factor means individual consumers’ peak demands do not coincide, allowing a power station with a fixed capacity to efficiently serve more consumers. This happens because the overall peak demand remains manageable despite the larger number of users, optimizing capacity utilization.

The increased load during summer months is because of

The increased load during summer months is because of

1. Increased business activity
2. Increased use of fans and air conditioners
3. Increased water supply
4. None of the above

Correct answer: 2. Increased use of fans and air conditioners

Explanation: During the summer months, temperatures typically rise, leading to increased use of cooling devices such as fans and air conditioners. These devices consume a significant amount of electricity, which in turn increases the overall load on the power supply system.

For diesel generating station the useful life is expected to be around

For diesel generating station the useful life is expected to be around

1. 10 to 15 years
2. 20 to 25 years
3. 50 to 75 years
4. 75 to 100 years

Correct answer: 2. 20 to 25 years

Explanation: While talking about useful life of generators, the first and most important factor to consider is usage. However, on average, diesel generators last from 10,000 to 30,000 hours of use. Usually, this equates to about 20-25 years of use.

Diversity factor has direct impact on

Diversity factor has direct impact on

1. Fixed cost of unit generated
2. Running cost of unit generated
3. Both of these
4. Neither of above

Correct answer: 1. Fixed cost of unit generated

Explanation: Diversity factor directly reduces fixed costs of unit generated by allowing for smaller infrastructure investments. It enables utilities to install less total generating capacity than the sum of individual peak demands, which lowers the capital required for power plants and transmission lines, consequently reducing the fixed costs per unit of electricity generated.

Power plant having maximum demand

Power plant having maximum demand more than the installed rated capacity will have utilization factor

1. Equal to unity
2. Less than unity
3. More than unity
4. None of these

Correct answer: 3. More than unity

Explanation: Power plant having maximum demand more than the installed rated capacity will have utilization factor more than unity.

Utilization Factor = Maximum Demand/Installed Rated Capacity

Let’s assume maximum demand is 20,000 and Installed rated capacity is 15,000 then:

Utilization Factor is 20,000/15,000 = 1.33

A low utilization factor for a plant implies that

A low utilization factor for a plant implies that

1. Plant is under maintenance
2. Plant is used for base load only
3. Plant is used for peak load as well as base load
4. Plant is used for stand by purpose only

Correct answer: 4. Plant is used for stand by purpose only

Explanation: Standby plants are meant to be used only when there is an extra demand or in case of emergency or failure of other plants. As such, these plants are generally not used regularly and have low utilization factors since they spend most of the time inactive, ready to operate only when needed.

Method that is not used for estimating depreciation charges

Which of the below mentioned is not a method for estimating depreciation charges

1. Diminishing value method
2. Halsey method
3. Sinking fund method
4. Straight line method

Correct answer: 2. Halsey

Explanation: The correct answer is “Halsey method.”

• Diminishing Value Method: A recognized depreciation method that applies a fixed rate to the decreasing book value of an asset each year.
• Straight Line Method: A common method where depreciation is evenly spread over the asset’s useful life.
• Sinking Fund Method: Although primarily used for accumulating funds to replace an asset, it can be associated with managing asset depreciation.

Halsey Method: This is not a depreciation method. Instead, it is a labor cost management technique that provides incentives for efficient work. Thus, it does not pertain to the estimation of depreciation charges.

Generating capacity type

Generating capacity connected to the bus bars and ready to take load when switched on is termed as

1. Cold reserve
2. Firm power
3. Hot reserve
4. Spinning reserve

Correct answer: 4. Spinning reserve

Explanation: Spinning reserve refers to the generating capacity that is connected, online, and ready to take additional load immediately or with minimal notice. This type of reserve is often running at a low operational level (spinning), so it can quickly ramp up when needed to meet sudden increases in demand or to compensate for a generator failure.

Major reason for low power factor is supply systems

The major reason for low power factor is supply system is due to installation of

1. DC Motors
2. Induction motors
3. Single phase motors
4. Synchronous motors

Correct answer: 2. Induction motors

Explanation: Induction motors are widely used in industrial settings and are inherently inductive loads, which draw significant reactive power. This reactive power contributes to a phase shift between current and voltage, resulting in a power factor that typically lags. This lagging power factor is a measure of power efficiency and becomes less efficient as more induction motors operate in a system. In contrast, synchronous motors can improve power factor by providing leading reactive power, and DC motors do not involve power factor issues as they run on direct current.

Find more description here: Why Induction Motors are often Associated with Low Power Factor

The power plant that generates power at unpredictable

The power plant that can generate power at unpredictable or uncontrolled times

1. Solar power plant
2. Tidal power plant
3. Wind power plant
4. All of these

Correct answer: 4. All of these

Explanation: Each option, Solar, Tidal, and Wind power plants, relies on natural conditions like sunlight, tidal patterns, and wind, which are unpredictable and uncontrollable. Therefore, all these power plants can generate power at unpredictable or uncontrolled times.

Which of following will offer the least load

Which of following will offer the least load

1. Electric shaver
2. Hair dryer
3. Television
4. Vacuum cleaner

Correct answer: 1. Electric shaver

Explanation: To determine which appliance offers the least load in terms of electrical power consumption, we need to compare the typical power usage of each:

1. Electric Shaver: Approximately 15-20 watts.
2. Hair Dryer: About 800-1800 watts.
3. Television: Roughly 70-400 watts.
4. Vacuum Cleaner: About 500-2000 watts.

Among these, the Electric Shaver uses the least power, typically only 15-20 watts. Therefore, it offers the least load compared to the other appliances listed.

A consumer has to pay lesser fixed charges in case of

A consumer has to pay lesser fixed charges in case of

1. Flat rate tariff
2. Maximum demand tariff
3. Two part tariff
4. Same in all of these

Correct answer: 2. Maximum demand tariff

Explanation: Maximum demand tariff features a fixed charge that is typically based on the highest level of electricity demand recorded during the billing period. This fixed charge is designed to cover the costs of ensuring sufficient capacity to meet the maximum demand of each customer. However, the focus is on accurately reflecting the cost of providing the maximum capacity needed rather than a flat service charge.

Most efficient plants are generally used as

Most efficient plants are generally used as

1. Base load plants
2. Peak load plants
3. Neither of above
4. Either of above

Correct answer: 1. Base load plants

Explanation: The most efficient plants are generally used as Base load plants. This is because they can operate continuously and efficiently, providing a constant supply of electricity at a lower cost. Efficient plants are ideal for base load use due to their ability to spread high capital costs over a larger amount of produced electricity, thereby reducing the cost per unit of energy and minimizing environmental impact.

Annual depreciation calculation as per straight line method

Annual depreciation as per straight line method, is calculated by

1. Increasing a uniform sum of money per annum at stipulated rate of interest
2. The capital cost divided by number of year of life
3. The capital cost minus the salvage value, is divided by the number of years of life
4. None of these

Correct answer: 3. The capital cost minus the salvage value, is divided by the number of years of life

Explanation: The correct answer is: “The capital cost minus the salvage value, is divided by the number of years of life.” This option correctly describes the straight-line method of depreciation, where the initial cost of the asset minus its estimated salvage value at the end of its useful life is divided by the number of years it is expected to be useful. This approach evenly spreads the depreciation expense over the asset’s useful life.

A synchronous condenser is virtually which of the following

A synchronous condenser is virtually which of the following

1. DC generator
2. Induction motor
3. Over excited synchronous motor
4. Under excited synchronous motor

Correct answer: 3. Over excited synchronous motor

Explanation: A synchronous condenser is essentially an over excited synchronous motor. It functions by being over excited to produce reactive power with a leading power factor. This device is used to manage and improve the power factor in electrical systems by compensating for lagging power factors typical in inductive loads. It adjusts excitation to control the flow of reactive power, thus optimizing the overall efficiency of the power system. Unlike under excited motors that exhibit a lagging power factor, over excited ones like synchronous condensers lead the current, hence their categorization as over excited synchronous motors.

Unfulfilled demand of consumers

When the demand of consumers is not met by a power plant, it will resort to

1. Efficient plant operation
2. Load shedding
3. Penalizing high load consumers by increasing the charges for electricity
4. Power factor improvement at generators

Correct answer: 2. Load shedding

Explanation: The correct answer is Load shedding. This is when a power company temporarily cuts off electricity to certain areas to prevent overloading the system, which can help avoid a total blackout when demand exceeds supply. Other options like increasing efficiency, penalizing high load consumers, or improving power factor don’t address the immediate shortage of supply directly like load shedding does.

Load curve helps in determining

Load curve helps in determining

1. Operating schedule of generating units
2. Sizes of the generating units
3. Total installed capacity of the plant
4. All of these

Correct answer: 4. All of these

Explanation: A load curve is a graphical representation showing the variation in demand or load on a power plant over a specific period. It helps in determining:

1. Operating schedule of generating units: It indicates when and how much power generation is needed to meet the load.
2. Sizes of the generating units: It helps in planning the sizes of units that can efficiently meet peak and average loads.
3. Total installed capacity of the plant: Ensuring sufficient capacity is available to meet the highest demand as shown on the load curve.

Generators for peak load plants are typically designed for maximum efficiency at

Generators for peak load plants are typically designed for maximum efficiency at

1. 25 percent overload
2. 25 to 50 percent full load
3. 50 to 75 percent full load
4. Full load

Correct answer: 3. 50 to 75 percent full load

Explanation: Generators for peak load plants are typically designed for maximum efficiency at 25 to 50 percent full load. Peak load plants operate only during periods of highest demand and thus do not run continuously. They need flexibility rather than maximum efficiency at full load. Designing for maximum efficiency at 25 to 50 percent full load allows these plants to operate efficiently during varying demand levels, typically not reaching or sustaining full capacity, which aligns with their operational requirements of being used less frequently but needing to be rapidly responsive and efficient when in use.

The efficiency of a plant is of least concern when it is used as

The efficiency of a plant is of least concern when it is used as

1. Casual run plant
2. Peak load plant
3. Either 1 or 2
4. Base load plant

Correct answer: 3. Either 1 or 2

Explanation: Peak load plants and casual run plants are designed to operate only during periods of high demand or occasionally, respectively. Since they do not run continuously, their operational costs and impacts on overall fuel consumption are less critical compared to continuous operations. Therefore, efficiency is of less concern for these types of plants compared to base load plants, which operate continuously and must be highly efficient to manage long-term operational costs effectively. Thus, the focus on efficiency is less critical for either peak load or casual run plants.

Which of the following is invariably used for peak load

Which of following is invariably used for peak load

1. Nuclear power plant
2. Pumped storage plant
3. Steam turbine plant
4. None of these

Correct answer: 2. Pumped storage plan

Explanation: Pumped storage plants are ideal for handling peak loads because they can quickly adjust their output to meet the fluctuating demand for electricity. These plants store energy during periods of low demand by pumping water to a higher elevation reservoir. During periods of high demand, the stored water is released to flow downhill through turbines, generating electricity quickly and efficiently. This ability to swiftly ramp up production makes pumped storage plants an optimal choice for managing peak load conditions, unlike nuclear or steam turbine plants, which have slower ramp-up times.

Which of the below-mentioned is not an operating cost

Which of the below-mentioned is not an operating cost

1. Fuel cost
2. Maintenance cost
3. Salaries of high officials
4. Salaries of operating staff

Correct answer: 3. Salaries of high officials

Explanation: Operating costs are expenses associated with the day-to-day functions of a business. These include costs like fuel, maintenance, and salaries of operating staff, all directly involved in the primary operations of a business. Salaries of high officials, however, are considered administrative costs because they relate to the overall management and administration of the company rather than the direct operation or production processes. Thus, salaries of high officials do not count as operating costs.

The disadvantage of low power factor is

The disadvantage of low power factor is

1. High cost of equipment for a given load
2. Increased transmission losses
3. Poor voltage regulation
4. All of these

Correct answer: 4. All of these

Explanation:

1. High cost of equipment for a given load: A low power factor requires larger equipment to handle the same amount of useful power, increasing infrastructure costs.
2. Increased transmission losses: Power losses in transmission lines are proportional to the square of the current. Low power factor increases the current for a given load, thus increasing losses.
3. Poor voltage regulation: High current flow due to low power factor leads to greater voltage drops across the transmission lines, resulting in poor voltage regulation at the consumer end.

All these factors contribute to the disadvantage of having a low power factor.

In two part tariff, variation in load factor will affect

In two part tariff, variation in load factor will affect

1. Fixed charges
2. Operating or running charges
3. Both of these
4. Either of 1 and 2

Correct answer: 2. Operating or running charges

Explanation: In a two-part tariff system, costs are divided into fixed charges, which are constant and do not depend on consumption or usage levels, and operating or running charges, which vary with the amount of electricity used. The load factor, which measures the actual electricity usage compared to the maximum possible usage over a period, affects the running charges because these charges are based on the actual consumption of electricity. Higher load factors imply more efficient usage of the electricity capacity, potentially impacting the variable costs or running charges. Fixed charges remain unaffected by changes in load factor since they are constant regardless of usage.

Direct conversion of heat into electrical energy can be achieved using

Direct conversion of heat into electrical energy can be achieved using

1. Fuel cells
2. MHD generators
3. Solar cells
4. None of the above

Correct answer: 2. MHD generators

Explanation: MHD (Magnetohydrodynamic) generators directly convert heat energy into electrical energy. This is achieved by heating a gas to a plasma state and then passing it through a magnetic field. The interaction between the charged particles in the plasma and the magnetic field generates electricity. Fuel cells generate electricity through chemical reactions rather than direct heat conversion, and solar cells convert light energy to electricity, not heat. Thus, MHD generators are the only option listed that specifically achieve the direct conversion of heat to electricity.

Reserved generating capacity for service under emergency conditions

Which of following is the reserved generating capacity available for service under emergency conditions which is not kept in operation but in working order

1. Cold reserve
2. Firm power
3. Hot reserve
4. Spinning reserve

Correct answer: 1. Cold reserve

Explanation: Cold reserve refers to generating capacity that is not currently operating but can be activated in case of an emergency. This capacity is maintained in working order but is not connected to the load and not immediately ready to deliver power. It typically requires some time to start up and synchronize to the grid. This contrasts with hot reserve and spinning reserve, both of which involve capacity that is either ready to deliver power immediately or running at minimum levels but synchronized and ready to increase output as needed. Firm power typically refers to power guaranteed to be available under contract, not a reserve type.

An alternator coupled to a mover runs slow

An alternator coupled to a XYZ runs at slow speed, as compared to others. XYZ can be replaced by

1. Diesel engine
2. Gas turbine
3. Hydraulic turbine
4. Steam turbine

Correct answer: 3. Hydraulic turbine

Explanation: Hydraulic turbines are typically used for generating electricity in hydropower plants and are known for operating effectively at lower rotational speeds compared to the other options. Diesel engines, gas turbines, and steam turbines generally operate at higher speeds. Hydraulic turbines can harness the kinetic energy of flowing or falling water to run an alternator at a slower, more controlled speed, making them ideal for settings that require lower-speed operations. Thus, for an alternator that runs at a slow speed, a hydraulic turbine is the most appropriate choice.

The generating station that has minimum running cost

The generating station that has minimum running cost

1. Diesel
2. Hydro
3. Nuclear
4. Thermal

Correct answer: 2. Hydro

Explanation: Hydroelectric power plants generally have the lowest running costs among the options provided. This is because, once constructed, the operational expenses are very low; they primarily involve maintenance costs and do not require fuel, as the energy is generated from flowing water. In contrast, diesel, nuclear, and thermal power stations have higher running costs due to the continuous need for fuel (diesel and coal/gas for thermal plants) and, in the case of nuclear, significant safety and regulatory management costs. Hydro plants leverage the natural water cycle, which is a free resource, resulting in minimal running costs.

Diversity Factor in Interconnected System

In an interconnected system, the diversity factor of the entire system

1. Decreases
2. Increases
3. Remains unchanged
4. None of the above

Correct answer: 2. Increases

Explanation: In an interconnected system, where multiple different power systems are connected, the diversity factor generally increases. This is because different systems often have varying peak demand times and patterns. By interconnecting these systems, the overall peak demand tends to be lower relative to the combined individual peaks of each system. This results in a higher diversity factor, indicating more efficient utilization of the total capacity. Essentially, the variations in demand across different regions or systems tend to average out, leading to a more stable and efficient system overall.

Load factor of a power station is defined as

Load factor of a power station is defined as

1. 2 * Average load * Maximum demand
2. Average load * Maximum demand
3. Average load/Maximum demand
4. Maximum demand/Average load

Correct answer: 3. Average load/Maximum demand

Explanation: The load factor of a power station is a measure of the efficiency of the power station’s usage over a period of time. It is defined as the ratio of the average load (the average power output or consumption over a period) to the maximum demand (the highest power output or consumption reached in that period). Therefore, the correct definition of load factor is:

Average load / Maximum demand

This metric is important because it indicates how effectively a power station utilizes its capacity. A higher load factor indicates more efficient use of capacity and energy resources.

The space required for a steam power station is

The space required for a steam power station is

1. Equal to diesel power station
2. Less than diesel power station
3. More than diesel power station
4. None of these

Correct answer: 3. More than diesel power station

Explanation: Steam power stations require more space compared to diesel power stations. This is because steam power plants have additional components like boilers, condensers, cooling towers, and various control structures. These components are necessary for the generation of steam and its condensation back into water. In contrast, diesel power stations have fewer components such as diesel engines and generators, which makes them more compact and requiring less space. Thus, steam power stations typically have a larger physical footprint than diesel power stations.

The draught in locomotive boilers is formed by

The draught in locomotive boilers is formed by

1. Chimney
2. Forced fan
3. Only motion of locomotive
4. Steam jet

Correct answer: 4. Steam jet

Explanation: In locomotive boilers, the draught is primarily formed by a steam jet. This method involves blowing exhaust steam from the engine’s cylinders into the smokestack, which enhances the draft (flow of air) through the firebox, pulling air into the boiler to intensify combustion. This mechanism is crucial because locomotives are mobile and need a consistent and controlled airflow to maintain the fire’s intensity, regardless of whether the locomotive is stationary or moving. Thus, the steam jet method is most effective and widely used in locomotives for generating the necessary draught.

Cooling section in the surface condenser

Cooling section in the surface condenser

1. Does not affect vapor quantity extracted but reduces pump capacity of air extraction pump
2. Increases the quantity of vapor extracted along with air
3. Reduces the quantity of vapor extracted along with air
4. None of these

Correct answer: 3. Reduces the quantity of vapor extracted along with air

Explanation: In a surface condenser, the cooling section’s primary function is to condense the steam by reducing its temperature through heat exchange with cooling water. When steam condenses into water, the volume of vapor decreases significantly. Consequently, the total volume of vapor and air mixture extracted by the air extraction pump also decreases, thus reducing the pump capacity needed. The reduction in vapor quantity occurs because condensation turns steam (vapor) into liquid water, leaving less vapor to be extracted alongside air.

Solar thermal power generation can be achieved by

Solar thermal power generation can be achieved by

1. Using a solar pond
2. Using flat plate collectors
3. Using focusing collector
4. Any of these

Correct answer: 4. Any of these

Explanation: The correct answer is “Any of these”. Here’s why:

1. Solar ponds generate heat through solar energy stored in their saltwater layers, used for power generation.
2. Flat plate collectors, typically for water heating, could theoretically be adapted for low-efficiency power generation.
3. Focusing collectors concentrate sunlight to produce high temperatures, ideal for generating steam to drive turbines.

Although focusing collectors are the most effective, all options can technically contribute to solar thermal power generation, making “Any of these” correct, albeit with varying degrees of efficiency and practical application.

The draught which a chimney produces is termed

The draught which a chimney produces is termed

1. Balanced draught
2. Forced draught
3. Induced draught
4. Natural draught

Correct answer: 4. Natural draught

Explanation: The draught produced by a chimney is termed “natural draught.” This occurs because the warmer, less dense air inside the chimney rises due to its buoyancy compared to the colder, denser outside air. As the warm air ascends and exits the chimney, it creates a pressure difference that pulls fresh air and combustion gases from the fireplace or furnace into and up through the chimney. This natural movement of air facilitates the combustion process in heating systems or fireplaces without the aid of mechanical fans or blowers.

Underfeed stokers suit which coal

Underfeed stokers work best for XYZ coals high in volatile matter and with caking tendency. Here XYZ implies

1. Anthracite
2. Lignite
3. Semi-bituminous and bituminous
4. All of above

Correct answer: 3. Semi-bituminous and bituminous

Explanation: Underfeed stokers are specifically efficient for coals with higher volatile matter content and a caking tendency because these stokers introduce coal from below the combustion zone, allowing the volatile compounds to burn as they rise through the hotter zones above. Semi-bituminous and bituminous coals typically have higher levels of volatile matter and exhibit a caking behavior, making them ideal for this type of stoker. Anthracite, having low volatile content, and lignite, being prone to moisture, do not fit as well with underfeed stokers compared to semi-bituminous and bituminous coals.

Friction losses Effects

The effect of considering friction losses in steam nozzle for same pressure ratio leads to

1. Decrease in exit velocity from the nozzle
2. Increase in exit velocity from the nozzle
3. Increase or decrease depending upon the exit quality of steam
4. No change in exit velocity from the nozzle

Correct answer: 1. Decrease in exit velocity from the nozzle

Explanation: When friction losses are considered in a steam nozzle, energy is lost due to friction. This reduces the kinetic energy available to accelerate the steam, resulting in a decrease in the exit velocity of the steam. Friction converts some of the mechanical energy into heat, which does not contribute to the acceleration of the steam flow, thus leading to a lower velocity at the nozzle exit compared to the ideal case where friction losses are not considered.

Compounding of steam turbine is done in order to

Compounding of steam turbine is done in order to

1. Balance the turbine
2. Increase the rotor speed
3. Reduce the rotor speed
4. Reduce the work done

Correct answer: 3. Reduce the rotor speed

Explanation: Compounding in steam turbines is primarily done to reduce the rotor speed. This is crucial because it helps manage the mechanical stresses and centrifugal forces acting on the turbine blades, which become significant at very high speeds. Lower speeds also facilitate the use of generators and other machinery directly connected to the turbine, which often require moderate rotational speeds to operate efficiently and safely. Compounding achieves this by distributing the pressure drop and workload over multiple stages or sets of blades, instead of having all the work done in a single stage, thus controlling the speed effectively.

Economizer is used to heat

Economizer is used to heat

1. Air
2. Feed water
3. Flue gases
4. All of above

Correct answer: 2. Feed water

Explanation: An economizer is used to heat feed water by utilizing the heat from flue gases. This process occurs before the feed water enters the boiler, thus increasing the thermal efficiency of the boiler by reducing the required heat input from the primary fuel. It captures the residual heat from the exhaust gases, which would otherwise be lost, and uses it to preheat the boiler’s incoming water, thereby saving energy and optimizing the boiler operation. Options “Air” and “Flue gases” are incorrect as economizers are specifically designed to heat water, not to heat air or to further heat flue gases.

The knowledge of diversity factor helps to find

The knowledge of diversity factor helps to find

1. Average load
2. Kwh generated
3. Peak load
4. Plant capacity

Correct answer: 4. Plant capacity

Explanation: The diversity factor helps in estimating the maximum load that a power generation plant or a distribution system needs to be able to handle at any given time, even though individual components or users within the system might not all reach their peak demand simultaneously. By taking into account the diversity factor, utility engineers can design a plant’s capacity more efficiently, ensuring it meets the maximum expected demand without significant overestimation, thereby optimizing resource usage and infrastructure investment. This makes it crucial for calculating the necessary plant capacity to meet these expected demands.

Power plant that cannot have single unit of 100 MW

Power plant that cannot have single unit of 100 MW

1. Diesel
2. Hydroelectric
3. Nuclear
4. Steam

Correct answer: 1. Diesel

Explanation: Diesel power plants typically consist of multiple smaller units rather than a single large unit due to the size and capacity limitations of diesel engines. While diesel engines are effective for small to medium-scale power production, they are not typically used for very large installations like 100 MW units. In contrast, hydroelectric, nuclear, and steam (thermal) power plants are capable of operating at much higher individual unit capacities, often exceeding 100 MW per unit, making them suitable for large-scale power generation needs.

Static capacitors are rated in terms of

Static capacitors are rated in terms of

1. Kvar
2. Kw
3. Kwh
4. None of these

Correct answer: 1. Kvar

Explanation: Static capacitors are primarily used for power factor correction in electrical systems. They provide reactive power to the system, which is measured in kilovolt-amperes reactive (Kvar). Unlike active power (measured in kilowatts, kW) which does useful work, or energy consumed over time (measured in kilowatt-hours, kWh), reactive power does not perform any work but is essential for maintaining voltage levels and efficient power system operation. Therefore, capacitors are rated in Kvar to indicate the amount of reactive power they can provide or absorb.

Power plant that is expected to have the longest life

Power plant that is expected to have the longest life

1. Diesel
2. Hydroelectric
3. Steam
4. Any of these

Correct answer: 2. Hydroelectric

Explanation: The correct answer is Hydroelectric. Hydroelectric power plants generally have the longest operational lifespan among the options listed. These facilities can operate and remain productive for 50 to 100 years or more. Hydroelectric power plants have minimal moving parts compared to diesel and steam plants, resulting in lower wear and tear. Additionally, they primarily depend on the availability of water and not on fuel that might run out or become too expensive. In contrast, diesel and steam plants typically have shorter lifespans due to the intense mechanical stresses and maintenance requirements associated with their operation.

Maximum demand on a power plant is

Maximum demand on a power plant is best described as

1. Instantaneous maximum value of kva supplied during a period
2. The greatest of all short time interval averaged demand during a period
3. Both of these
4. None of these

Correct answer: 2. The greatest of all short time interval averaged demand during a period

Explanation: Maximum demand on a power plant refers to the highest level of power demand averaged over a specific period (usually ranging from 15 minutes to an hour), recorded during a longer monitoring period (such as a month or a year). It is not the instantaneous maximum value of kVA, which would reflect peak power at a single moment. Rather, maximum demand represents the peak average demand sustained over the designated short time interval within the overall period, crucial for planning and capacity management of power systems.

The load factor of domestic load is typically

The load factor of domestic load is typically

1. 10 to 15%
2. 30 to 40%
3. 50 to 60%
4. 60 to 70%

Correct answer: 1. 10 to 15%

Explanation: Load factor is defined as the ratio of average load to the maximum demand during a given period of time. See complete Formula, Definition and Applications of Load Factor by ElectricalEngineering.XYZ here

Which of the following is not a power source

Which of the following is not a power source

1. Photoelectric cell
2. Photovoltaic cell
3. Solar cell
4. Thermocouple

Correct answer: 4. Thermocouple

Explanation: A photoelectric cell, photovoltaic cell, and solar cell are all devices that convert light energy into electrical energy. A thermocouple, on the other hand, does not generate power from a primary energy source. Instead, it measures temperature differences and converts that thermal gradient into a small voltage used for measurement, not as a significant power source. Thus, it is not primarily a power source but a sensor.

Also see: Basic Construction and Working of Thermocouple here

Load curve is useful in deciding the

Load curve is useful in deciding the

1. Operating schedule of generating units
2. Sizes of generating units
3. Total installed capacity of the plant
4. All of these

Correct answer: 4. All of these

A load curve, which graphs the variation in electrical demand or load against time, is crucial for multiple aspects of power system management. It helps in determining:

1. Operating schedule of generating units: By analyzing demand patterns, utilities can decide when to operate or shut down units.
2. Sizes of generating units: Understanding peak and average demands aids in selecting appropriately sized generating units to handle these variations efficiently.
3. Total installed capacity of the plant: The load curve indicates the maximum demand, guiding decisions on the total capacity needed to meet peak loads reliably.

Power factor can be improved using

Power factor can be improved using

1. Phase advancers
2. Static capacitors
3. Synchronous compensators
4. Any of the above

Correct answer: 4. Any of the above

Explanation: Power factor can be improved by methods that adjust the phase difference between voltage and current, thereby reducing the reactive power component and enhancing efficiency. Phase advancers are used mainly with induction motors to advance the phase of rotor current, static capacitors provide leading reactive power to counteract the lagging reactive power typically consumed by inductive loads, and synchronous compensators (which are a type of synchronous motor) can be adjusted to supply or absorb reactive power. Each of these methods effectively improves the power factor in electrical systems.

Also see: Impact of Power Factor on Handling Capacity of System

Fuel transportation cost is least in case of

Fuel transportation cost is least in case of

1. Diesel generating plants
2. Nuclear power plants
3. Steam power stations
4. Same in all of these

Correct answer: 2. Nuclear power plants

Explanation: The unique feature of the nuclear plant is the enormous power capability of nuclear fuel.

Nuclear power plants require relatively little fuel in terms of volume compared to the amount of energy they produce because nuclear fuel is extremely energy-dense. Therefore, the transportation costs of this fuel are lower compared to the bulkier fuels needed for diesel and steam power plants (which primarily burn coal, oil, or gas). Thus, even though nuclear fuel must be handled with caution due to its radioactivity, the overall transportation cost is still the least because of the small quantity needed to produce significant amounts of power.

Also see: In case of which power plant fuel transportation is the major problem

A load curve shows

A load curve shows

1. Average power used during the period
2. Only maximum demand
3. Load factor only
4. Cost of electricity charged to end user

Correct answer: 1. Average power used during the period

Explanation: A load curve is a graphical representation of the power used by a system or area over a period of time. It shows the variation in power demand throughout the period (like a day or a year), reflecting the actual load or power consumption at different times. It is not typically used to directly display energy consumption in kWh; instead, it shows the power in kW at various times, from which energy consumption can be calculated by considering the time period over which the power is used.

Also see: Highest point on daily load curve represents

In a thermal power plant, the cost that is not fixed

In a thermal power plant, the cost that is not fixed

1. Depreciation
2. Fuel cost
3. Insurance charges
4. Interest on capital

Correct answer: 2. Fuel cost

The salvage value of the plant is always

The salvage value of the plant is always

1. Negative
2. Positive
3. Zero
4. Any of the above

Correct answer: 4. Any of the above

The maintenance cost is usually high in case of

The maintenance cost is usually high in case of

1. Diesel engine power plants
2. Hydro-electric power plants
3. Nuclear power plant
4. Thermal power plants

Correct answer: 4. Thermal power plants

Also see: 5 Types of Electrical Equipment at Hydro Power Plants

The power source that is least reliable

The power source that is least reliable

1. Geothermal power
2. MHD
3. Solar energy
4. Wind power

Correct answer: 4. Wind power

With reference to a power stations which of the following is not a fixed cost

With reference to a power stations which of the following is not a fixed cost

1. Depreciation
2. Fuel cost
3. Insurance charges
4. Interest on capital

Correct answer: 2. Fuel cost

Annual depreciation of the plant is proportional to the earning capacity of the plant vide

Annual depreciation of the plant is proportional to the earning capacity of the plant vide

1. Reducing balances depreciation
2. Sinking fund depreciation
3. Straight line depreciation
4. None of these

Correct answer: 1. Reducing balances depreciation

Depreciation charges are high in case of

Depreciation charges are high in case of

1. Diesel plant
2. Hydroelectric plant
3. Thermal plant
4. same in all of these

Correct answer: 3. Thermal plant

In power plants insurance cover is provided for

In power plants insurance cover is provided for

1. Equipment only
2. Skilled workers only
3. Unskilled workers only
4. All of the above

Correct answer: 4. All of the above

Load curve of a power plant has always

Load curve of a power plant has always

1. Negative slope
2. Positive slope
3. Zero slope
4. Any combination of above

Correct answer: 4. Any combination of above

Submarines for under water movement, are powered by

Submarines for under water movement, are powered by

1. Air motors
2. Batteries
3. Diesel engines
4. Steam accumulators

Correct answer: 2. Batteries

Which of following is not necessarily an advantage of interconnecting various power stations

Which of following is not necessarily an advantage of interconnecting various power stations

1. Economy in operation of plants
2. Improved frequency of power supplied
3. Increased reliability
4. Reduction in total installed capacity

Correct answer: 2. Improved frequency of power supplied

For any type of consumer, the ideal tariff is

For any type of consumer, the ideal tariff is

1. Block rate tariff
2. Three-part tariff
3. Two-part tariff
4. All of above

Correct answer: 2. Three-part tariff

Also see: Maximum demand Tarriff here

Load factor of a power station is usually

Load factor of a power station is usually

1. Equal to unity
2. Equal to zero Diversity factor is always
3. Less than unity
4. More than unity

Correct answer: 3. Less than unity

An induction motor has relatively high power factor at

An induction motor has relatively high power factor at

1. 20 percent load
2. Near full load
3. No load
4. Rated RPM

Correct answer: 2. Near full load

The equipment that provides fluctuating load

The equipment that provides fluctuating load

1. Exhaust fan
2. Lathe machine
3. Welding transformer
4. All of these

Correct answer: 3. Welding transformer

Annual instalment towards depreciation reduces as rate of interest increases with

Annual instalment towards depreciation reduces as rate of interest increases with

1. Reducing balances depreciation
2. Sinking fund depreciation
3. Straight line depreciation
4. None of these

Correct answer: 2. Sinking fund depreciation

The power plant that can never have 100 percent load factor

The power plant that can never have 100 percent load factor

1. Base load plant
2. Hydroelectric plant
3. Nuclear power plant
4. Peak load plant

Correct answer: 4. Peak load plant

For a consumer the most economical power factor is usually

For a consumer the most economical power factor is usually

1. 0.5 lagging
2. 0.5 leading
3. 0.95 lagging
4. 0.95 leading

Correct answer: 3. 0.95 lagging

A pilot exciter is provided on generators so as

A pilot exciter is provided on generators so as

1. To excite the poles of main exciter
2. To provide requisite starting torque to generator
3. To provide requisite starting torque to main exciter
4. None of these

Correct answer: 1. To excite the poles of main exciter

The device that may be used to provide protection against lightening over voltages

The device that may be used to provide protection against lightening over voltages

1. Horn gaps
2. Rod gaps
3. Surge absorbers
4. All of these

Correct answer: 4. All of these

The expected useful life of the hydroelectric power plant is about

The expected useful life of the hydroelectric power plant is about

1. 100 years
2. 15 years
3. 30 years
4. 60 years

Correct answer: 1. 100 years

Which of the below mentioned are not repayable after a stipulated period

Which of the below mentioned are not repayable after a stipulated period

1. Bonds
2. Cash certificates
3. Fixed deposits
4. Shares

Correct answer: 4. Shares

Air will not be the working substance in case of

Air will not be the working substance in case of

1. Closed cycle gas turbine
2. Diesel engine
3. Open cycle gas turbine
4. Petrol engine

Correct answer: 1. Closed cycle gas turbine