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.
Contents
- 1 The primary source of energy in the universe is
- 2 The largest source of power generation at present
- 3 Alternator converts ____________ to __________
- 4 The term pulverized features the fuel of
- 5 Low heads employ
- 6 Spillway belongs to which structure
- 7 The condenser in which there is no direct contact between steam and water
- 8 The analysis which provides the complete chemical analysis of coal
- 9 Which of the following doesn’t belong to full admission turbine
- 10 The direction of turbines is reversed in
- 11 In a distribution system, in order to improve power factor, the synchronous capacitors are installed
- 12 During load shedding
- 13 The essential requirement of peak load plant is that
- 14 An over excited synchronous motor on no-load is termed as
- 15 The area under a load curve gives
- 16 Which of following will be least affected due to charge in supply voltage frequency
- 17 The power plant that is invariably used as base load plant
- 18 Which of the below mentioned is the disadvantage of static capacitor for power factor improvement
- 19 For high value of diversity factor, a power station
- 20 The increased load during summer months is because of
- 21 For diesel generating station the useful life is expected to be around
- 22 Diversity factor has direct impact on
- 23 Power plant having maximum demand
- 24 A low utilization factor for a plant implies that
- 25 Method that is not used for estimating depreciation charges
- 26 Generating capacity type
- 27 Major reason for low power factor is supply systems
- 28 The power plant that generates power at unpredictable
- 29 Which of following will offer the least load
- 30 A consumer has to pay lesser fixed charges in case of
- 31 Most efficient plants are generally used as
- 32 Annual depreciation calculation as per straight line method
- 33 A synchronous condenser is virtually which of the following
- 34 Unfulfilled demand of consumers
- 35 Load curve helps in determining
- 36 Generators for peak load plants are typically designed for maximum efficiency at
- 37 The efficiency of a plant is of least concern when it is used as
- 38 Which of the following is invariably used for peak load
- 39 Which of the below-mentioned is not an operating cost
- 40 The disadvantage of low power factor is
- 41 In two part tariff, variation in load factor will affect
- 42 Direct conversion of heat into electrical energy can be achieved using
- 43 Reserved generating capacity for service under emergency conditions
- 44 An alternator coupled to a mover runs slow
- 45 The generating station that has minimum running cost
- 46 Diversity Factor in Interconnected System
- 47 Load factor of a power station is defined as
- 48 The space required for a steam power station is
- 49 The draught in locomotive boilers is formed by
- 50 Cooling section in the surface condenser
- 51 Solar thermal power generation can be achieved by
- 52 The draught which a chimney produces is termed
- 53 Underfeed stokers suit which coal
- 54 Friction losses Effects
- 55 Compounding of steam turbine is done in order to
- 56 Economizer is used to heat
- 57 The knowledge of diversity factor helps to find
- 58 Power plant that cannot have single unit of 100 MW
- 59 Static capacitors are rated in terms of
- 60 Power plant that is expected to have the longest life
- 61 Maximum demand on a power plant is
- 62 The load factor of domestic load is typically
- 63 Which of the following is not a power source
- 64 Load curve is useful in deciding the
- 65 Power factor can be improved using
- 66 Fuel transportation cost is least in case of
- 67 A load curve shows
- 68 In a thermal power plant, the cost that is not fixed
- 69 The salvage value of the plant is always
- 70 The maintenance cost is usually high in case of
- 71 The power source that is least reliable
- 72 Depreciation charges are high in case of
- 73 In power plants insurance cover is provided for
- 74 Load curve of a power plant has always
- 75 Submarines for under water movement, are powered by
- 76 Load factor of a power station is usually
- 77 The equipment that provides fluctuating load
- 78 Annual installment towards depreciation
- 79 The power plant that can never have 100 percent load factor
- 80 For a consumer the most economical power factor is usually
- 81 The expected useful life of the hydroelectric power plant is about
- 82 Which of the below mentioned are not repayable after a stipulated period
- 83 Air will not be the working substance in case of
- 84 The power plant that takes least time in starting
- 85 The output power of a nuclear power station is proportional to
- 86 Graphite is used in nuclear plant as
- 87 Deflectors are provided in
- 88 An impulse turbine is used for
- 89 A gas turbine works on which cycle
- 90 The conversion ratio of breeder reactor are
- 91 Pipes carrying steam are generally made of
- 92 A CANDU reactor uses
- 93 Power Factor For maximum transmission efficiency
- 94 For maximum efficiency Gas turbine power plants have
- 95 In case of steam power plant, the efficiency of Rankine cycle is
- 96 The function of reflector in nuclear power station is to
- 97 Which of following is not a conventional energy source
- 98 In hydro power plant surge tank is located near
- 99 Determination of Storage requirement in case of hydro power plants
- 100 Water hammer is developed in which part of hydropower plant
- 101 In thermal power plants, pressure in working fluid cycle is developed by
- 102 Which of following are the fertile materials
- 103 The problem of noise is most eminent in
- 104 Heat produced by 1 kg of atomic fuel is equivalent to heat produced from coal of weight
- 105 The power plant which is usually employed in the emergency conditions is
- 106 Tidal energy primarily uses
- 107 Area under the daily load curve divided by 24 hrs gives
The primary source of energy in the universe is
The primary source of energy in the universe is:
- Fuels
- Wind
- Water
- 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:
- Coal
- Nuclear
- Water
- Oil
Correct answer: 1. Coal
Explanation:
2019 world electricity generation by source (total generation was 27 PWh)
- Coal (37%)
- Natural gas (24%)
- Hydro (16%)
- Nuclear (10%)
- Wind (5%)
- Solar (3%)
- Other (5%)
Source: https://www.iea.org/data-and-statistics/charts/world-gross-electricity-production-by-source-2019
Alternator converts ____________ to __________
Alternator converts ____________ to __________:
- Mechanical, Electrical (AC)
- Electrical (AC), Mechanical
- Mechanical, Electrical (DC)
- 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:
- Gas power station
- DAM
- Steam power station
- 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:
- Impulse turbine
- Francis turbine
- Propeller turbine
- 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:
- Hydroelectric power plant
- Steam power station
- Nuclear power station
- 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.
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:
- Jet condenser
- Surface condenser
- Both of these
- 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:
- Ultimate analysis
- Proximate analysis
- Breath analysis
- 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:
- Propeller
- Francis
- Kaplan
- Pelton
Correct answer: 4. Pelton
The direction of turbines is reversed in
The direction of turbines is reversed in:
- Run-of-the-river plants
- Pumped storage plants
- Storage plants
- 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
- At the receiving end
- At the sending end
- Either of above
- None of above
Correct answer: 1. At the receiving end
During load shedding
During load shedding
- Some loads are switched off
- System frequency is reduced
- System power factor is changed
- 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
- It should be capable of starting quickly
- It should be small in size
- It should produce high voltage
- 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
- Alternator
- Generator
- Induction motor
- 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
- Average demand
- Energy consumed
- Maximum demand
- 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
- Ceiling fan
- Electric clock
- Mixer grinder
- 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
- Diesel engine plant
- Gas turbine plant
- Nuclear power plant
- 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
- Cannot be repaired
- Easily damaged by high voltage
- Short service life
- All of the above
Correct answer: 4. All of the above
Explanation: Each listed disadvantage pertains to static capacitors used in power factor improvement:
- Cannot be repaired – Static capacitors typically require replacement rather than repair upon failure.
- Easily damaged by high voltage – Capacitors can be damaged by voltage spikes exceeding their rated capacity.
- 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
- Less number of consumers
- More number of consumers
- Neither of above
- 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
- Increased business activity
- Increased use of fans and air conditioners
- Increased water supply
- 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
- 10 to 15 years
- 20 to 25 years
- 50 to 75 years
- 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
- Fixed cost of unit generated
- Running cost of unit generated
- Both of these
- 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
- Equal to unity
- Less than unity
- More than unity
- 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
- Plant is under maintenance
- Plant is used for base load only
- Plant is used for peak load as well as base load
- 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
- Diminishing value method
- Halsey method
- Sinking fund method
- 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
- Cold reserve
- Firm power
- Hot reserve
- 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
- DC Motors
- Induction motors
- Single phase motors
- 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
- Solar power plant
- Tidal power plant
- Wind power plant
- 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
- Electric shaver
- Hair dryer
- Television
- 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:
- Electric Shaver: Approximately 15-20 watts.
- Hair Dryer: About 800-1800 watts.
- Television: Roughly 70-400 watts.
- 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
- Flat rate tariff
- Maximum demand tariff
- Two part tariff
- 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
- Base load plants
- Peak load plants
- Neither of above
- 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
- Increasing a uniform sum of money per annum at stipulated rate of interest
- The capital cost divided by number of year of life
- The capital cost minus the salvage value, is divided by the number of years of life
- 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
- DC generator
- Induction motor
- Over excited synchronous motor
- 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
- Efficient plant operation
- Load shedding
- Penalizing high load consumers by increasing the charges for electricity
- 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
- Operating schedule of generating units
- Sizes of the generating units
- Total installed capacity of the plant
- 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:
- Operating schedule of generating units: It indicates when and how much power generation is needed to meet the load.
- Sizes of the generating units: It helps in planning the sizes of units that can efficiently meet peak and average loads.
- 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
- 25 percent overload
- 25 to 50 percent full load
- 50 to 75 percent full load
- 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
- Casual run plant
- Peak load plant
- Either 1 or 2
- 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
- Nuclear power plant
- Pumped storage plant
- Steam turbine plant
- 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
- Fuel cost
- Maintenance cost
- Salaries of high officials
- 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
- High cost of equipment for a given load
- Increased transmission losses
- Poor voltage regulation
- All of these
Correct answer: 4. All of these
Explanation:
- 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.
- 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.
- 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
- Fixed charges
- Operating or running charges
- Both of these
- 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
- Fuel cells
- MHD generators
- Solar cells
- 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
- Cold reserve
- Firm power
- Hot reserve
- 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
- Diesel engine
- Gas turbine
- Hydraulic turbine
- 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
- Diesel
- Hydro
- Nuclear
- 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
- Decreases
- Increases
- Remains unchanged
- 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
- 2 * Average load * Maximum demand
- Average load * Maximum demand
- Average load/Maximum demand
- 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
- Equal to diesel power station
- Less than diesel power station
- More than diesel power station
- 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
- Chimney
- Forced fan
- Only motion of locomotive
- 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
- Does not affect vapor quantity extracted but reduces pump capacity of air extraction pump
- Increases the quantity of vapor extracted along with air
- Reduces the quantity of vapor extracted along with air
- 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
- Using a solar pond
- Using flat plate collectors
- Using focusing collector
- Any of these
Correct answer: 4. Any of these
Explanation: The correct answer is “Any of these”. Here’s why:
- Solar ponds generate heat through solar energy stored in their saltwater layers, used for power generation.
- Flat plate collectors, typically for water heating, could theoretically be adapted for low-efficiency power generation.
- 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
- Balanced draught
- Forced draught
- Induced draught
- 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
- Anthracite
- Lignite
- Semi-bituminous and bituminous
- 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
- Decrease in exit velocity from the nozzle
- Increase in exit velocity from the nozzle
- Increase or decrease depending upon the exit quality of steam
- 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
- Balance the turbine
- Increase the rotor speed
- Reduce the rotor speed
- 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
- Air
- Feed water
- Flue gases
- 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
- Average load
- Kwh generated
- Peak load
- 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
- Diesel
- Hydroelectric
- Nuclear
- 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
- Kvar
- Kw
- Kwh
- 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
- Diesel
- Hydroelectric
- Steam
- 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
- Instantaneous maximum value of kva supplied during a period
- The greatest of all short time interval averaged demand during a period
- Both of these
- 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
- 10 to 15%
- 30 to 40%
- 50 to 60%
- 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
- Photoelectric cell
- Photovoltaic cell
- Solar cell
- 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
- Operating schedule of generating units
- Sizes of generating units
- Total installed capacity of the plant
- 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:
- Operating schedule of generating units: By analyzing demand patterns, utilities can decide when to operate or shut down units.
- Sizes of generating units: Understanding peak and average demands aids in selecting appropriately sized generating units to handle these variations efficiently.
- 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
- Phase advancers
- Static capacitors
- Synchronous compensators
- 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
- Diesel generating plants
- Nuclear power plants
- Steam power stations
- 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
- Average power used during the period
- Only maximum demand
- Load factor only
- 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
- Depreciation
- Fuel cost
- Insurance charges
- Interest on capital
Correct answer: 2. Fuel cost
Explanation: The correct answer to the question about which cost in a thermal power plant is not fixed is: Fuel cost.
Here’s why:
- Depreciation: This is considered a fixed cost. Depreciation is the accounting process of allocating the cost of a tangible asset over its useful life. In the context of a thermal power plant, this could involve the depreciation of equipment and buildings. It is a non-cash expense that does not vary with the level of output.
- Fuel Cost: This is a variable cost. Fuel cost varies directly with the amount of electricity generated. In thermal power plants, fuel (such as coal, gas, or oil) is burned to generate electricity. Therefore, the more electricity the plant produces, the more fuel it consumes. Hence, fuel costs will increase with higher production levels and decrease with lower production levels.
- Insurance Charges: This is generally a fixed cost. Insurance premiums for a thermal power plant are usually paid on a regular basis (e.g., annually) and do not typically vary with the level of production or operation of the plant.
- Interest on Capital: This is also a fixed cost. Interest on capital refers to the interest payments made on any borrowed funds or bonds used to finance the plant’s construction or operations. These payments are predetermined and do not vary with the plant’s operational levels.
Thus, among the given options, fuel cost is the one that is not fixed, as it changes with the level of output of the power plant.
The salvage value of the plant is always
The salvage value of the plant is always
- Negative
- Positive
- Zero
- Any of the above
Correct answer: 4. Any of the above
Explanation: The correct answer is Any of the above. The salvage value of a plant can vary: it may be positive if the asset retains value, zero if it’s fully depreciated or obsolete, or negative if disposal costs exceed its value. This variability depends on the asset’s condition, market demand, and associated disposal costs at the end of its useful life. Thus, the salvage value of a plant isn’t fixed and can fall into any of these categories based on specific circumstances.
The maintenance cost is usually high in case of
The maintenance cost is usually high in case of
- Diesel engine power plants
- Hydro-electric power plants
- Nuclear power plant
- Coal power plant
Correct answer: 3. Nuclear power plant
Explanation: Nuclear power plants have the highest maintenance costs compared to diesel engine, hydro-electric, and thermal power plants. This is because nuclear plants involve complex safety systems and procedures to handle radioactive materials. Frequent regulatory checks, meticulous operational standards, and the need for specialized staff contribute to higher maintenance expenses. In contrast, hydro-electric plants typically have lower maintenance costs due to fewer moving parts and less stringent regulatory requirements, while diesel and thermal plants, though varied in cost, generally do not reach the high maintenance cost levels of nuclear facilities.
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
- Geothermal power
- MHD
- Solar energy
- Wind power
Correct answer: 4. Wind power
Explanation: Wind power can indeed be considered less reliable among the options given, depending on specific circumstances such as geographic location and meteorological conditions. Wind power generation requires wind, and its availability can be unpredictable and vary greatly, more so than solar, which at least has predictable daylight hours despite being affected by weather. Geothermal is generally stable, and while MHD (Magneto Hydrodynamic) is less common, it doesn’t depend as heavily on fluctuating natural conditions as wind power does. Therefore, in areas where wind patterns are not consistent, wind power would be the least reliable source.
Depreciation charges are high in case of
Depreciation charges are high in case of
- Diesel plant
- Hydroelectric plant
- Thermal plants
- Same in all of these
Correct answer: 3. Thermal plant
Explanation: Thermal power plants often involve substantial initial capital costs due to the complexity and scale of their machinery and infrastructure, such as boilers, turbines, and generators, all of which depreciate over time. They also experience higher wear and tear due to operating at high temperatures and pressures, which accelerates the depreciation. This contrasts with hydroelectric plants, which have simpler, more durable structures like dams and turbines that degrade more slowly. Diesel plants, while having high operational costs, do not generally match the scale of capital investment and rate of depreciation found in large thermal power plants.
In power plants insurance cover is provided for
In power plants insurance cover is provided for
- Equipment only
- Skilled workers only
- Unskilled workers only
- All of the above
Correct answer: 4. All of the above
Explanation: In power plants, insurance cover is provided for All of the above: equipment, skilled workers, and unskilled workers. Equipment insurance covers damage or loss of machinery. Skilled and unskilled workers are covered by worker’s compensation insurance or similar policies that protect against work-related injuries or fatalities. This comprehensive coverage ensures operational stability and safety compliance. Insurance for all elements — both human resources and physical assets — is essential for mitigating risks associated with power plant operations.
Load curve of a power plant has always
Load curve of a power plant has always
- Negative slope
- Positive slope
- Zero slope
- Any combination of above
Correct answer: 4. Any combination of above
Explanation: A load curve represents the variation of electrical load or power consumption with respect to time. Throughout a typical day, the power demand can increase, decrease, or remain constant at different times. During peak hours, the slope can be positive as demand rises. Conversely, the slope becomes negative as demand falls after peak hours. At certain times, the demand might be stable, resulting in a zero slope. Therefore, a load curve can exhibit a positive slope, negative slope, or zero slope depending on the time of day and varying demand, which leads to any combination of the above slopes.
Submarines for under water movement, are powered by
Submarines for under water movement, are powered by
- Air motors
- Batteries
- Diesel engines
- Steam accumulators
Correct answer: 2. Batteries
Explanation: Submarines typically use diesel engines when operating on the surface or near the surface, where they can intake air for combustion. However, when submerged, they switch to electric motors powered by batteries for quieter and air-independent propulsion. The combination allows submarines to be versatile in different operational environments. Diesel engines provide power to charge the batteries and for direct propulsion when air is accessible, while batteries power the submarine silently when submerged. Air motors and steam accumulators are not standard power sources for modern submarines.
Load factor of a power station is usually
Load factor of a power station is usually
- Equal to unity
- Equal to zero Diversity factor is always
- Less than unity
- More than unity
Correct answer: 3. Less than unity
Explanation: The load factor of a power station is the ratio of average load to the maximum load during a specific period. It is less than unity because the average load is generally less than the maximum load.
The diversity factor refers to the ratio of the sum of the individual maximum demands of various subdivisions of a system to the maximum demand of the whole system. It is more than unity, reflecting that not all subdivisions peak at the same time, leading to a total maximum demand that is less than the sum of individual peaks.
The equipment that provides fluctuating load
The equipment that provides fluctuating load
- Exhaust fan
- Lathe machine
- Welding transformer
- All of these
Correct answer: 3. Welding transformer
Explanation: This equipment experiences fluctuating load primarily due to the variable current demands during the welding process. Different welding jobs require different amounts of power, and adjustments are often made based on the thickness of the material and type of weld needed. Therefore, the welding transformer’s load fluctuates significantly as it adapts to these varying requirements.
Annual installment towards depreciation
Annual installment towards depreciation reduces as rate of interest increases with
- Reducing balances depreciation
- Sinking fund depreciation
- Straight line depreciation
- None of these
Correct answer: 2. Sinking fund depreciation
Explanation: In sinking fund depreciation, a company sets aside money each year in a fund that accumulates interest to replace an asset at the end of its useful life. The annual installment into the sinking fund depends on the interest rate: the higher the interest rate, the less money needs to be set aside each year to reach the future value required for replacing the asset. This is because the money in the fund grows faster due to higher interest, reducing the annual contribution needed. Reducing balances and straight line depreciation methods involve constant or variable depreciation charges based on the asset’s value, not influenced by interest rates.
The power plant that can never have 100 percent load factor
The power plant that can never have 100 percent load factor
- Base load plant
- Hydroelectric plant
- Nuclear power plant
- Peak load plant
Correct answer: 4. Peak load plant
Explanation: A peak load plant is designed to operate only during times of highest demand. Unlike base load plants (such as nuclear or coal-fired plants, which are efficient when running continuously) or hydroelectric plants (which can also provide base or peak power depending on water availability and storage capabilities), peak load plants specifically cater to demand surges, typically operating for a shorter duration. Consequently, peak load plants cannot achieve a 100% load factor, as their operation is intermittent and not continuous. Their primary role is to balance and support the grid during peak demand times, not to operate constantly.
For a consumer the most economical power factor is usually
For a consumer the most economical power factor is usually
- 0.5 lagging
- 0.5 leading
- 0.95 lagging
- 0.95 leading
Correct answer: 3. 0.95 lagging
Explanation: The most economical power factor for a consumer is usually 0.95 lagging. This is because utilities often charge higher rates for electricity consumption when the power factor is low (far from 1), whether lagging or leading, as it causes inefficiencies in the power supply system. A power factor close to 1 (but typically lagging, as inductive loads are more common) minimizes these inefficiencies, reducing energy loss and potentially avoiding extra charges. Therefore, maintaining a power factor around 0.95 lagging helps in reducing the cost of electricity consumption by decreasing the reactive power component.
The expected useful life of the hydroelectric power plant is about
The expected useful life of the hydroelectric power plant is about
- 100 years
- 15 years
- 30 years
- 60 years
Correct answer: 1. 100 years
Explanation: The expected useful life of a hydroelectric power plant is about 100 years. Hydroelectric power plants are designed with durable infrastructure such as concrete dams and robust mechanical equipment. These components have long lifespans due to their ability to withstand environmental stresses and continuous use. The design and construction standards enable such plants to operate effectively for many decades, often reaching or exceeding a century. This lifespan exceeds that of many other power generation facilities, making the 100-year choice the most accurate among the provided options.
Which of the below mentioned are not repayable after a stipulated period
Which of the below mentioned are not repayable after a stipulated period
- Bonds
- Cash certificates
- Fixed deposits
- Shares
Correct answer: 4. Shares
Explanation: Shares represent equity ownership in a company and entitle the holder to a share of the company’s profits through dividends, if declared, and to vote in company meetings. Unlike bonds, cash certificates, and fixed deposits, which are debt instruments with a specific term after which they are repayable, shares do not have a maturity date and are not repayable at a stipulated period. The return on shares comes from dividend payments and potential capital gains, not repayment of principal.
Air will not be the working substance in case of
Air will not be the working substance in case of
- Closed cycle gas turbine
- Diesel engine
- Open cycle gas turbine
- Petrol engine
Correct answer: 1. Closed cycle gas turbine
Explanation: In a closed cycle gas turbine, the working fluid (like helium or another gas) is recirculated within the system. Unlike open cycle gas turbines where air is taken in, used, and expelled, a closed cycle system does not exchange air with the environment. Therefore, air is not the working substance in closed cycle gas turbines, making this the correct answer.
The power plant that takes least time in starting
The power plant that takes least time in starting from cold condition to full load operation
- Gas turbine plant
- Hydroelectric power plant
- Nuclear power plant
- Thermal power plant
Correct answer: 2. Hydroelectric power plant
The output power of a nuclear power station is proportional to
The output power of a nuclear power station is proportional to
- Square of the rate at which fission reaction occurs
- Square root of the rate at which fission reaction occurs
- The rate at which fission reaction occurs
- None of above
Correct answer: 3. The rate at which fission reaction occurs
Graphite is used in nuclear plant as
Graphite is used in nuclear plant as
- Coolant
- Electrode
- Fuel
- Moderator
Correct answer: 4. Moderator
Explanation: Graphite is used in nuclear plant as moderator. The moderator in nuclear power plant is intentionally placed in a nuclear reactor core to slow neutrons down from their initial fast speeds. Utilizing a moderator in nuclear plants makes it much easier to attain a nuclear chain reaction.
Graphite is used in a reactor to slow down high-velocity neutrons, thereby increasing the likelihood of fission.
Deflectors are provided in
Deflectors are provided in
- Francis turbine
- Kaplan turbine
- Pelton wheel
- Propeller turbine
Correct answer: 3. Pelton wheel
An impulse turbine is used for
An impulse turbine is used for:
- Low water head
- Medium water head
- High water head
- None of these
Correct answer: 3. High water head
Explanation: Classification of Hydroelectric plants on the basis of Head:
- Low head powerplants: < 15 m
- Medium head powerplants: 15-70 m
- High head powerplants: 71-250 m
- Very-high head powerplants: Greater than 250 m
A gas turbine works on which cycle
A gas turbine works on which cycle
- Brayton cycle
- Carnot cycle
- Dual cycle
- Rankine cycle
Correct answer: 1. Brayton cycle
The video below serves an excellent illustration of Brayton cycle:
The conversion ratio of breeder reactor are
The conversion ratio of breeder reactor are
- 1
- Less than 1
- Greater than 1
- None of above
Correct answer: 3. Greater than 1
Explanation: Breeder reactors are type of nuclear reactors that generates more fissile material than it consumes. Fast breeder reactors can convert more fertile material to fissile material and therefore net fuel conversion ratio is greater than 1.
Pipes carrying steam are generally made of
Pipes carrying steam are generally made of
- Aluminum
- Cobalt
- Cast iron
- Steel
Correct answer: 4. Steel
A CANDU reactor uses
A CANDU reactor uses
- Enriched uranium as fuel and ordinary water as moderator and cooler
- Highly enriched uranium as fuel and water as moderator and coolant
- Natural uranium as fuel and heavy water as moderator and coolant
- Only fertile materials
Correct answer: 3. Natural uranium as fuel and heavy water as moderator and coolant
The word CANDU is an abbreviation for Canadian Deuterium uranium.
A CANDU reactor uses heavy water composed of the heavy hydrogen isotope as moderator to have maximum neutron economy and as a coolant as well.
Power Factor For maximum transmission efficiency
For maximum efficiency in transmission of bulk ac power, power factor load should be:
- Slightly less than unity lagging
- Slightly less than unity leading
- Considerably less than unity
- Unity
Correct answer: 1. Slightly less than unity lagging
For maximum efficiency Gas turbine power plants have
Gas turbine power plants for maximum efficiency may have
- Heat exchangers
- Multistage compression
- Reheating
- All of these
Correct answer: 4. All of these
Explanation: In order to achieve maximum efficiency, gas turbine power plants utilize heat exchangers, multistage compression and reheating. The reheating process utilizes the heat of exhaust gases to heat the compressed air before it is sent to the combustion chamber. It reduces the fuel consumption of the plant and improves the efficiency to maximum possible value. For multistage compression, the inlet temperature of turbine and pressure rate increases, the heat supplied as well as the heat rejected are reduced. However, the rate of change of heat supplied as well as the heat supplied is not same as the rate of change heat rejected. As a result, there exists an optimum pressure ratio producing maximum efficiency for a given turbine inlet temperature.
In case of steam power plant, the efficiency of Rankine cycle is
In case of steam power plant, the efficiency of Rankine cycle is:
- 60 – 80%
- 45 – 80%
- 30 – 45%
- 20 – 30%
Correct answer: 3. 30 – 45%
Explanation: In case of steam power plant the efficiency of Rankine cycle is in the range of 30-45%. The efficiency of the Rankine cycle is limited by the high heat of vaporization of working steam.
See also: Coal power plant
The function of reflector in nuclear power station is to
The function of reflector in nuclear power station is to
- Bounce back most of the neutrons that escape from the fuel core
- Reduce the speed of the neutrons
- Stop the chain reaction
- None of above
Correct answer: 1. Bounce back most of the neutrons that escape from the fuel core
Explanation: The reflector is nuclear power plant is a layer of material immediately surrounding a reactor core that scatters back (or reflects) into the core many neutrons that would otherwise escape. The presence of reflector in a plant results in returned neutrons that can then cause more fissions and improve the neutron economy of the reactor. This in turn conserves the nuclear fuel as the low speed neutrons thus returned are useful in continuing the chain reaction.
Which of following is not a conventional energy source
Which of following is not a conventional energy source
- Geothermal
- Nuclear
- Tidal
- Wind
Correct answer: 4. Wind
In hydro power plant surge tank is located near
In hydro power plant surge tank is located near
- Dam
- Reservoir
- Transformer
- Turbine
Correct answer: 4. Turbine
Determination of Storage requirement in case of hydro power plants
Storage requirement in case of hydro power plants can be determined from
- Hydro-graph
- Mass curve
- Both of these
- None of these
Correct answer: 3. Both of these
Water hammer is developed in which part of hydropower plant
Water hammer is developed in a
- Draft tube
- Penstock
- Surge tank
- Turbine
Correct answer: 2. Penstock
In thermal power plants, pressure in working fluid cycle is developed by
In thermal power plants, pressure in working fluid cycle is developed by:
- Condenser
- Feed water pump
- Super heater
- Turbine
Correct answer: 3. Super heater
Also see: Top 5 Advantages of Steam Power Station
Which of following are the fertile materials
Which of following are the fertile materials
- U233 and Pu239
- U238 and Pu239
- U238 and Th232
- U238 and Th239
Correct answer: 3. U238 and Th232
Explanation: Fertile material is defined as a material, which itself is not fissile (fissionable by thermal neutrons), that can be converted into a fissile material by irradiation in a reactor. There are two basic fertile materials: uranium-238 and thorium-232.
The problem of noise is most eminent in
The problem of noise is most eminent in
- Nuclear power station
- Diesel power station
- Hydroelectric power station
- Steam power station
Correct answer: 2. Steam power station
Heat produced by 1 kg of atomic fuel is equivalent to heat produced from coal of weight
Heat produced by 1 kg of atomic fuel is equivalent to heat produced from coal of weight:
- 1 ton
- 100 ton
- 1000 tons
- 4230 tons
Correct answer: 4. 4230 tons
The power plant which is usually employed in the emergency conditions is
The power plant which is usually employed in the emergency conditions is:
- Hydroelectric power station
- Diesel power station
- Tidal unit station
- Steam power station
Correct answer: 2. Diesel power station
Tidal energy primarily uses
Tidal energy primarily uses:
- Kinetic energy of water
- Potential energy of water
- Both of these
- None of these
Correct answer: 3. Both of these
Area under the daily load curve divided by 24 hrs gives
Area under the daily load curve divided by 24 hrs gives:
- Units generated
- Maximum demand
- Average load
- None of these
Correct answer: 3. Average load
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