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Past Questions
The coal is reduced to a fine powder with the help of grinding mill and then projected into the combustion chamber with the help of hot air current is known as
A)
Pulverized fuel firing
B)
Mantial fuel firing
C)
Non-Pulverized fuel firing
D)
None of these
Step-by-step reasoning: 1. The process described involves grinding coal into a fine powder (pulverization) using a grinding mill. 2. This powder is then transported into the furnace/combustion chamber using a high-velocity stream of hot air (primary air). 3. This specific method is known as 'Pulverized Fuel Firing'. It allows for more complete combustion, higher efficiency, and the ability to burn lower-grade coals compared to stoker-fired systems. 4. Option 'b' (Mantial fuel firing) is not a standard engineering term in boiler technology. 5. Option 'c' (Non-Pulverized fuel firing) refers to methods like grate firing or fluidization where coal is burned in larger chunks, which contradicts the description of using a grinding mill.
A closed vessel made of high quality steel in which stream is generated from water by the application of heat, is known as
A)
Steam nozzle
B)
Steam Generator (or) a boiler
C)
Steam Jet Draught
D)
None of these
Step-by-step reasoning:
1. Definition Analysis: The question describes a 'closed vessel' made of 'high quality steel' used to generate 'steam from water' via 'heat'. This is the fundamental engineering definition of a boiler.
2. Evaluating Option (b): A boiler (or steam generator) is specifically designed to transfer heat from a fuel source (combustion or electrical) to water to produce steam at a desired pressure and temperature. This matches all criteria in the question.
3. Evaluating Option (a): A steam nozzle is a device used to convert the thermal energy (pressure) of steam into kinetic energy (velocity) by expanding the steam; it does not generate steam from water.
4. Evaluating Option (c): A steam jet draught is a system used to create a vacuum or a draft in a furnace using a jet of high-pressure steam; it is a mechanism for air/gas flow, not for steam generation.
5. Conclusion: Since option (b) is the only device that fits the description of a vessel for steam generation, it is the correct answer.
Control of temperature, humidity, purity and motion of air in an enclosed space, independent of outside conditions is known as
A)
Air-conditioning
B)
Air-circulating
C)
Flow-controlling
D)
None of these
The definition provided in the question is the standard technical definition of Air-conditioning. Air-conditioning is the process of treating air to control its temperature (heating or cooling), humidity (humidifying or dehumidifying), purity (filtering), and motion (distribution/velocity) to create a desired indoor environment regardless of the external weather conditions.
Why other options are incorrect:
- b. Air-circulating: This refers only to the movement of air within a space (e.g., using a fan) and does not involve controlling temperature, humidity, or purity.
- c. Flow-controlling: This is a general term used in fluid mechanics or HVAC ducting to regulate the volume of air moving through a system, but it does not encompass the comprehensive environmental control described in the question.
Which part is not common between the SI engine and CI engines
A)
Fuel Injector
B)
Air Cleaner
C)
Battery
D)
Exhaust Silencer
Fuel injector is not common between SI and CI engines because SI (spark ignition) engines use a carburetor or fuel injection system to supply a premixed air-fuel charge, while CI (compression ignition) engines must use a fuel injector to inject diesel directly into the hot compressed air. The other options are common to both engines: an exhaust silencer is used in both to reduce exhaust noise, an air cleaner is used in both to filter intake air, and a battery is commonly used in both for starting and electrical supply (especially in modern vehicles).
In internal combustion engine the approximate percentage of the combustion heat that passes to the cylinder walls is
A)
5%
B)
10%
C)
30%
D)
60% or 75%
In an Internal Combustion (IC) engine, the heat energy released during the combustion of fuel is distributed among several paths. A typical heat balance sheet for a spark-ignition or compression-ignition engine shows the following approximate distribution:
1. Useful Work (Brake Power): Approximately 25% to 35%.
2. Heat carried away by cooling water/cylinder walls: Approximately 30% to 35%.
3. Heat carried away by exhaust gases: Approximately 30% to 40%.
4. Radiation and friction losses: Approximately 5% to 10%.
Comparing this to the given options:
- Option (a) 5% and (b) 10% are too low and typically represent radiation or friction losses.
- Option (d) 60% or 75% is too high; if this much heat went to the walls, the engine would be extremely inefficient and the cooling system would be oversized.
- Option (c) 30% aligns with the standard thermodynamic heat balance of a typical IC engine, where roughly one-third of the total heat is absorbed by the cylinder walls and removed by the coolant.
A closed vessel heat exchanger in which steam coming from turbine is condensed using a supply of cooling water at atmospheric pressure
A)
Steam Engine
B)
Heat Exchanger
C)
Condenser
D)
None of these
Step-by-step reasoning: 1. The question describes a device that takes steam coming from a turbine and converts it back into water (condenses it). 2. This process is achieved by transferring heat from the steam to a cooling medium (cooling water). 3. By definition, a 'Condenser' is a heat exchanger specifically designed to condense a vapor into a liquid. In a power plant cycle (Rankine cycle), the condenser is located after the turbine to create a vacuum, which increases the pressure drop across the turbine and thereby increases the overall thermal efficiency of the plant. 4. Evaluating other options: (a) A Steam Engine is a prime mover that uses steam to produce mechanical work, not a vessel for condensation. (b) 'Heat Exchanger' is a general category of equipment; while a condenser is a type of heat exchanger, 'Condenser' is the specific and most accurate term for this function. (d) 'None of these' is incorrect as option (c) is the precise technical term.
Which one is not components of cost
A)
Prime cost
B)
Factory cost & Office cost
C)
Total cost
D)
Note of these
In Industrial Engineering and Cost Accounting, the total cost of a product is broken down into several hierarchical components.
1. **Prime Cost**: This is the sum of direct materials, direct labor, and direct expenses. It is the most basic component of cost.
2. **Factory Cost (or Works Cost)**: This is calculated by adding factory overheads to the Prime Cost.
3. **Office Cost (or Cost of Production)**: This is calculated by adding administrative/office overheads to the Factory Cost.
4. **Total Cost (or Cost of Sales)**: This is the final sum after adding selling and distribution overheads to the Cost of Production.
Since Prime Cost, Factory Cost, Office Cost, and Total Cost are all recognized components/stages of cost accumulation in a manufacturing process, none of the options (a, b, or c) are 'not components of cost'. Therefore, the correct choice is 'Note of these' (which is a typographical error for 'None of these').
Y is in the East of X which is in the North of Z. If P is in the South of Z, then in which direction of Y, is P?
A)
North
B)
South
C)
South-East
D)
None of these
Let's map the positions step-by-step using a coordinate system where North is up, South is down, East is right, and West is left:
1. 'X which is in the North of Z': This means X is above Z. (Z is the reference point).
2. 'Y is in the East of X': This means Y is to the right of X.
3. 'P is in the South of Z': This means P is below Z.
Now, let's determine the position of P relative to Y:
- Y is to the East (right) of the X-Z-P vertical line.
- P is the southernmost point in this arrangement.
- To get from Y to P, you must move West (to reach the vertical line) and then South (to reach P).
Therefore, P is in the South-West direction of Y.
Evaluating the options:
a. North: Incorrect.
b. South: Incorrect (P is South and West of Y).
c. South-East: Incorrect (P is to the West of Y).
d. None of these: Correct, as the actual direction is South-West.
Which one is not any types of gas turbine cycles
A)
Otto cycle
B)
Open cycle
C)
Closed cycle
To determine which option is not a type of gas turbine cycle, we must analyze the thermodynamic cycles associated with gas turbines and internal combustion engines:
1. **Gas Turbine Cycles**: Gas turbines typically operate on the **Brayton cycle**. Depending on how the working fluid is handled, they are categorized into:
- **Open Cycle**: The working fluid (air) is drawn from the atmosphere, compressed, heated by combustion, expanded through the turbine, and then exhausted back into the atmosphere. This is the most common type used in aircraft engines.
- **Closed Cycle**: The working fluid is circulated in a closed loop. It is heated by an external heat exchanger and cooled by a heat sink, meaning the same fluid is reused.
2. **Otto Cycle**: The Otto cycle is the idealized thermodynamic cycle for **spark-ignition internal combustion engines** (like gasoline engines). It involves constant-volume heat addition, which is fundamentally different from the constant-pressure heat addition found in the Brayton cycle used by gas turbines.
Therefore, while Open and Closed cycles are classifications of gas turbine operation, the Otto cycle is a reciprocating engine cycle, not a gas turbine cycle.
The principle of a radiator of an Engine Cooling System is to
A)
Act as a reservoir for the water
B)
Cause heat flow by convection currents
C)
Spread out the hot water over a large area
D)
Increase the air speed as it flows over the hot surface
The primary function of a radiator in an engine cooling system is to facilitate the transfer of heat from the coolant (water/antifreeze) to the surrounding air. According to the laws of heat transfer, the rate of heat dissipation is directly proportional to the surface area of the heat exchanger (Newton's Law of Cooling: Q = hAΔT). To maximize the cooling efficiency, the radiator uses a network of small tubes and numerous thin fins to 'spread out' the hot coolant over a very large surface area. This maximizes the contact area between the hot coolant and the cooling air, allowing heat to be dissipated more rapidly.
Why other options are incorrect:
- Option (a): While the radiator holds coolant, its 'principle' is heat exchange, not storage. The expansion tank acts as the primary reservoir.
- Option (b): While convection occurs, the radiator's specific design principle is about increasing the surface area for that convection to be effective; convection currents alone (without the area increase) would be insufficient to cool a high-performance engine.
- Option (d): The radiator does not increase air speed; air speed is increased by the vehicle's motion or by a mechanical fan, which then flows over the radiator's surface.
The artificial withdrawal of heat, producing in a substance or within a space, a temperature lower than that which would exist under the natural influence of surrounding is known as
A)
Regeneration
B)
Refrigeration
C)
Reheating
D)
None of these
The question provides the formal thermodynamic definition of refrigeration.
1. **Refrigeration (Correct):** By definition, refrigeration is the process of removing heat from a space or a substance to lower its temperature below that of the surrounding environment. This is achieved by using a refrigerant and a refrigeration cycle (like the Vapor Compression Cycle) to move heat from a low-temperature reservoir to a high-temperature reservoir, which requires external work.
2. **Regeneration (Incorrect):** In thermodynamics, regeneration is the process of recovering heat from a working fluid (like exhaust gas) to preheat another fluid entering the system, thereby increasing the overall efficiency of a cycle (e.g., in Gas Turbines or Rankine cycles).
3. **Reheating (Incorrect):** Reheating is the process of adding heat back into a working fluid after it has undergone an initial expansion process (common in steam power plants) to increase the work output and prevent moisture formation in the turbine.
Therefore, the artificial withdrawal of heat to maintain a temperature lower than the surroundings is specifically known as refrigeration.
A four-cylinder engine has a capacity of 2.4 litres. The swept volume of one cylinder is
A)
2400 cm³
B)
600 cm³
C)
1200 cm³
D)
400 cm³
Step-by-step calculation:
1. **Understand Engine Capacity**: The total capacity (or displacement) of an engine is the sum of the swept volumes of all its cylinders.
2. **Given Data**:
- Total Capacity = 2.4 litres
- Number of cylinders = 4
3. **Unit Conversion**: Since the options are in cubic centimeters (cm³), we must convert litres to cm³.
- 1 litre = 1000 cm³
- Total Capacity = 2.4 × 1000 = 2400 cm³
4. **Calculate Swept Volume per Cylinder**: Since the engine has 4 cylinders, the swept volume of one cylinder is the total capacity divided by the number of cylinders.
- Swept Volume = Total Capacity / Number of Cylinders
- Swept Volume = 2400 cm³ / 4 = 600 cm³
Comparing this to the options:
- Option (a) 2400 cm³ is the total capacity of the engine, not a single cylinder.
- Option (b) 600 cm³ matches our calculation.
- Option (c) 1200 cm³ would be the capacity for a 2-cylinder engine of this size.
- Option (d) 400 cm³ is mathematically incorrect for this total capacity.
The type of engine used in heavy commercial vehicle is
A)
External Combustion
B)
Petrol
C)
Diesel
D)
Spark Ignition
Step-by-step reasoning: 1. Heavy commercial vehicles (such as trucks, buses, and tractors) require high torque at low speeds to move heavy loads. 2. Diesel engines operate on the Compression Ignition (CI) principle, which allows for higher compression ratios compared to petrol engines. 3. Higher compression ratios result in higher thermal efficiency and significantly greater torque output, making them ideal for heavy-duty applications. 4. Additionally, diesel fuel has a higher energy density per gallon than petrol, providing better fuel economy for long-haul transport. Analysis of other options: (a) External Combustion engines (like steam engines) are too bulky and inefficient for mobile vehicles. (b) Petrol engines and (d) Spark Ignition engines (which are essentially the same thing) are typically used in light-duty vehicles because they provide higher speed and smoother operation but lack the torque and efficiency required for heavy commercial loads.
An engine has a clearance volume of 100cm³ and swept volume of 800cm³. The compression ratio is
A)
7:1
B)
9:1
C)
10:1
D)
8:1
Step-by-step calculation:
1. Identify the given values:
- Clearance Volume (Vc) = 100 cm³
- Swept Volume (Vs) = 800 cm³
2. Understand the formula for Compression Ratio (r):
The compression ratio is the ratio of the total cylinder volume (when the piston is at Bottom Dead Center - BDC) to the clearance volume (when the piston is at Top Dead Center - TDC).
Formula: r = (Vs + Vc) / Vc
3. Substitute the values into the formula:
r = (800 + 100) / 100
r = 900 / 100
r = 9
4. Express as a ratio:
The compression ratio is 9:1.
Comparing this result to the options:
- Option a (7:1) is incorrect.
- Option b (9:1) matches our calculation.
- Option c (10:1) is incorrect.
- Option d (8:1) is incorrect.
The firing order in case of four cylinder in-line engine is usually
A)
1-2-4-3
B)
1-3-4-2
C)
1-4-3-2
D)
Either (b) or (c)
In a four-cylinder in-line engine, the firing order is designed to minimize engine vibration and balance the reciprocating masses to ensure smooth operation. The most common and standard firing order for a four-cylinder engine is 1-3-4-2. This sequence ensures that the power strokes are evenly distributed across the crankshaft, preventing excessive torsional stress and reducing the center of gravity's oscillation. While some specific engines might use 1-2-4-3, the 'usual' or industry-standard convention taught in mechanical engineering and used in the majority of automotive applications is 1-3-4-2. Option (a) is less common, and options (c) and (d) are generally not used as standard firing orders for balanced in-line four-cylinder engines.
Brake lining is mounted on
A)
Brake shoe
B)
Place Turni
C)
Master Cylinder
D)
Wheel Cylinder
In a drum brake system, the brake lining is the friction material that is riveted or bonded to the outer surface of the brake shoe. When the brakes are applied, the wheel cylinder pushes the brake shoe outward, forcing the brake lining against the inner surface of the rotating brake drum, creating the friction necessary to stop the vehicle.
Why other options are incorrect:
- b. Place Turni: This appears to be a typographical error or a non-technical term and has no relevance to braking components.
- c. Master Cylinder: This is the primary pump that converts pedal pressure into hydraulic pressure; it does not hold friction linings.
- d. Wheel Cylinder: This is the hydraulic actuator that pushes the brake shoes; while it interacts with the shoe, the lining is not mounted on the cylinder itself.
Indirect Expenses is known as overhead charges, on-cost, burden or indirect charges. Which one is not included in classification of Indirect Expenses.
A)
Factory expenses
B)
Administration & Selling expenses
C)
Distribution expenses
D)
None of these
In Industrial Engineering and Cost Accounting, Indirect Expenses (also known as overheads, on-costs, or burden) are costs that cannot be directly traced to a specific unit of production. They are typically classified into three main categories: 1. Factory Overheads (e.g., factory rent, power, depreciation of machinery), 2. Administration Overheads (e.g., office salaries, legal fees), and 3. Selling and Distribution Overheads (e.g., advertising, delivery van expenses, warehouse rent). Since options (a) Factory expenses, (b) Administration & Selling expenses, and (c) Distribution expenses are all standard classifications of indirect expenses, none of them are 'not included'. Therefore, the correct answer is 'None of these'.
One effect of a punctured carburettor float is
A)
Weak mixture
B)
Low petrol level
C)
High air fuel mixture
D)
Petrol flooding
In a carburettor, the float mechanism acts as a valve controller to maintain a constant level of fuel in the float chamber. The float is a buoyant device that rises as the fuel level increases; once it reaches a specific height, it pushes a needle valve shut, stopping the flow of fuel from the fuel tank into the chamber. If the float is punctured, it loses its buoyancy and sinks to the bottom of the chamber. Because the float cannot rise, it fails to push the needle valve shut, allowing fuel to flow continuously into the chamber. This leads to an overflow of fuel, known as 'petrol flooding,' which can leak out of the carburettor or enter the intake manifold in excessive quantities, causing the engine to stall or fail to start due to an overly rich mixture.
Radiator tubes are generally made of
A)
Steel
B)
Brass
C)
Cast Iron
D)
Plastics
Radiator tubes must possess three primary characteristics: high thermal conductivity to transfer heat from the coolant to the air, resistance to corrosion (since they are constantly exposed to water and coolant), and malleability for manufacturing thin-walled tubes.
1. Brass (an alloy of copper and zinc) is the traditional and most common material for radiator tubes because it offers an excellent balance of high thermal conductivity and superior corrosion resistance.
2. Steel (Option a) has lower thermal conductivity than brass and is highly susceptible to rust/corrosion unless heavily coated.
3. Cast Iron (Option c) is far too heavy, has poor thermal conductivity compared to brass, and is brittle, making it unsuitable for thin tubes.
4. Plastics (Option d) are used for the radiator tanks (end tanks) in modern radiators to reduce weight and cost, but they cannot be used for the tubes themselves because they are thermal insulators and would not allow heat to escape the coolant.
IC engine includes
A)
Diesel Engine
B)
Petrol Engine
C)
Spark Ignition Engine
D)
Any of the above
An Internal Combustion (IC) engine is a heat engine where the combustion of fuel occurs inside a combustion chamber.
1. Petrol Engines: These are IC engines that use gasoline and typically utilize a spark plug to ignite the fuel-air mixture.
2. Diesel Engines: These are IC engines that use diesel fuel and rely on compression ignition (the heat generated by high compression) to ignite the fuel.
3. Spark Ignition (SI) Engines: This is a category of IC engines (which includes petrol engines) where a spark is used to initiate combustion.
Since all three options (a, b, and c) are types or categories of Internal Combustion engines, the correct answer is 'Any of the above'.
The door of a running refrigerator inside a room was left open. Which of the following statements is correct?
A)
The room will be cooled to the temperature inside the refrigerator
B)
The room will be cooled very slightly
C)
The room will be gradually warmed up
D)
The temperature of the air in room will remained unaffected
Refrigerator motor adds work to heat pumped, net heat rejected warms room.
If a gas vapour is allowed to expand through a very minute aperture, then such a process is known as-
A)
Free expansion
B)
Hyperbolic expansion
C)
Adiabatic expansion
D)
Throttling
Expansion through minute aperture with no work and isenthalpic is throttling process.
Compressor used in Window Air Conditioner is -
A)
Rotary
B)
Reciprocating compressor
C)
Sealed compressor
D)
Open type compressor
Window AC commonly uses hermetically sealed rotary compressor for compact size, listed as rotary.
Normal depth in open channel flow is the depth of flow corresponding to -
A)
Unsteady flow
B)
Uniform flow
C)
Laminar flow
D)
Steady flow
Normal depth is uniform flow depth where gravity balances friction in open channel.
The fuel mostly used in steam boilers is -
A)
Non-coking bituminous coal
B)
Brown coal
C)
Peat
D)
Coking bituminous coal
Non-coking bituminous coal is widely used in steam boilers due to good calorific value and free burning.