Mmv 1st Year Online Test

The statement is true. The distance between the top dead center (TDC) and bottom dead center (BDC) of a piston in an engine is referred to as the stroke. The stroke represents the total distance the piston travels during its up and down motion within the cylinder.

The tool used to check the flatness of a cylinder head is a straight edge and filler gauge. A straight edge is a flat, rigid tool that is placed across the surface of the cylinder head to check for any deviations or unevenness. The filler gauge is used to measure the gap between the straight edge and the cylinder head, allowing for precise measurement of any irregularities. This method ensures that the cylinder head is perfectly flat, which is crucial for proper engine performance and sealing.

Die is a tool used to cut or form threads on the outside surface of a cylindrical workpiece. It is commonly used to create external threads, which are threads on the outside of a screw or bolt. By using a die, the workpiece can be threaded to match the corresponding internal threads of another component, allowing them to be joined together securely. Therefore, die is primarily used for cutting external threads.

The least count of a vernier depth gauge is the smallest measurement that can be accurately read or measured using the instrument. In this case, the correct answer is 0.02 mm, which means that the vernier depth gauge can accurately measure up to 0.02 mm increments. This means that any measurement taken with this instrument will be accurate to within 0.02 mm.

When the speed of the engine is increased, it means that the engine is operating at a higher RPM (revolutions per minute). This increase in speed leads to an increase in the number of power strokes per minute, resulting in a higher indicated power. Therefore, the correct answer is Increase.

Scavenging is a process in which the exhaust gases are removed from the engine cylinder and replaced with fresh air. This ensures that there is a sufficient supply of fresh air in the engine cylinder for the combustion process. By removing the exhaust gases, the scavenging process helps to improve the efficiency of the combustion and overall performance of the engine.

An adjustable reamer is a type of cutting tool used to enlarge or shape holes in metal or wood. It consists of a handle with a threaded adjustment mechanism and a cutting blade. The blade can be adjusted to achieve the desired hole size, making it a versatile tool for various applications. The other options, such as a drill bit or reamer, are different types of cutting tools used for specific purposes and are not adjustable like the adjustable reamer. Therefore, the correct answer is Adjustable reamer.

Acetylene gas is formed by the reaction of calcium carbide and water. When calcium carbide reacts with water, it produces acetylene gas as one of the products. This reaction is commonly used in industrial processes to produce acetylene gas, which has various applications such as welding and cutting metals. The other options, carbon dioxide and water, oxygen and water, and none of these, do not result in the formation of acetylene gas when reacted together.

Lubricating oil serves multiple purposes in machinery. It minimizes wear in moving parts by reducing friction between them, thereby prolonging their lifespan. It also helps in keeping the parts cool by dissipating heat generated during operation. Additionally, lubricating oil acts as a cleaning agent as it washes away and carries away dirt and debris that may accumulate in the machinery. Therefore, all of the given options are correct as they describe the various functions of lubricating oil.

During combustion in the engine, the peak temperature in the cylinder can reach up to 3300°C. This high temperature is achieved due to the rapid and intense burning of the fuel-air mixture. The combustion process releases a large amount of energy, causing the temperature to rise significantly. This extreme temperature is necessary for efficient combustion and power generation in the engine.

A cylinder bore gauge is a tool used to measure the internal diameter of a cylinder. It is specifically designed to accurately measure the size of the bore in engine cylinders. This tool is commonly used in automotive and mechanical engineering industries to ensure proper cylinder dimensions for optimal engine performance. It typically consists of a gauge head with adjustable anvils that can be inserted into the cylinder to measure its diameter. The correct answer is "Cylinder bore gauge" as it accurately describes the tool's purpose and function.

When three 12V 20amp batteries are connected in parallel, the voltage remains the same (12V) while the current adds up. Therefore, the output will be 12V with a total current of 60amp.

When petrol is used in a diesel engine, higher knocking will occur. Knocking refers to the uncontrolled combustion of fuel in the engine's cylinders, which can cause damage to the engine. Petrol has a lower ignition point compared to diesel, and its combustion characteristics are different. As a result, using petrol in a diesel engine can lead to abnormal combustion, causing knocking. This can be detrimental to the engine's performance and longevity.

Centrifugal compressors are generally used as turbochargers. They are designed to increase the pressure and density of the air entering the engine, which in turn improves the engine's performance. These compressors use centrifugal force to accelerate the air and then convert the kinetic energy into pressure. They are commonly used in automotive and industrial applications where a compact and efficient compressor is required.

The given statement, "OR GATE is also known as an inverter gate," is false. An OR gate is a logic gate that performs the logical OR operation, while an inverter gate (also known as a NOT gate) performs the logical inversion of its input. These two gates serve different functions in logic circuits, so they are not interchangeable.

The dry sump system is the correct answer because in this system, the lubricating oil is stored in a separate tank rather than in the engine's sump. The oil is pumped from the tank to the engine, providing a constant supply of oil and allowing for better lubrication and cooling of the engine components. This system is commonly used in high-performance and racing engines as it helps to prevent oil starvation during high-speed and high-force maneuvers.

The catalytic converter is responsible for controlling the emissions of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) in a vehicle's exhaust system. It uses a catalyst to facilitate chemical reactions that convert these harmful pollutants into less harmful substances before they are released into the atmosphere.

The octane number is a measure of the ignition quality of petrol. It indicates the resistance of petrol to knocking or pinging in a combustion engine. A higher octane number means that the petrol has a higher resistance to knocking and can withstand higher compression ratios without premature ignition. Therefore, the octane number is a crucial factor in determining the performance and efficiency of a petrol engine.

The correct answer is Maroon. In oxy-acetylene welding, the color of the fuel cylinder is maroon. This is because the fuel used in this process is acetylene, which is stored in cylinders that are typically painted maroon to distinguish them from other cylinders used for different gases. The maroon color helps to ensure that the correct fuel is being used and prevents any confusion or mix-up with other gases.

A screw jack is used when we need linear motion. This type of jack converts rotational motion into linear motion by using a screw mechanism. As the screw is rotated, it moves up or down along the threads, causing the load to move in a linear direction. Therefore, a screw jack is suitable for applications that require lifting or lowering heavy loads in a straight line.

The part shown in the photo is identified as a crescent pump.

The indicated power of a 4-stroke engine is calculated by multiplying the effective pressure (p), stroke length (L), and area of the piston (A). The formula for the indicated power is pLAN. However, the given answer is pLAN/2, which means that the indicated power is half of the calculated value. This could be due to various factors such as frictional losses, mechanical inefficiencies, or other factors that reduce the actual power output of the engine.

The use of a pressure cap on the radiator increases air pressure within the cooling system. This is because the pressure cap is designed to regulate and maintain the pressure in the radiator at a specific level. As the coolant heats up and expands, the pressure cap allows excess pressure to be released into the overflow tank. When the engine cools down, the pressure cap allows coolant to be drawn back into the radiator, creating a higher pressure environment. This increased pressure helps to raise the boiling point of the coolant and prevent overheating.

The minimum reading accuracy of a steel rule is 1/64 inch. This means that the smallest measurement that can be accurately read on the steel rule is 1/64 of an inch.

Carbon di-oxide is not considered one of the six major pollutants according to the EPA of USA. The six major pollutants, also known as criteria pollutants, are ozone, carbon monoxide, nitrogen oxides, sulfur dioxide, particulate matter, and lead. Carbon di-oxide is not listed among these pollutants because it is a naturally occurring gas that is essential for life and is not directly harmful to human health in the same way as the other pollutants.

The flywheel is responsible for smoothening power impulses from the engine. It is a heavy rotating disc that stores kinetic energy and helps to maintain a consistent rotational speed of the engine. The flywheel absorbs and stores excess energy during the power stroke and releases it during the compression stroke, resulting in a more even and continuous power delivery. This helps to reduce vibrations and fluctuations in engine speed, providing a smoother operation overall.

Washers are used to distribute force over a large area. When a bolt or nut is tightened, it exerts pressure on the surface it is fastened to. By using a washer, this force is spread out over a larger surface area, reducing the pressure on the material and preventing damage or deformation. This helps to evenly distribute the force and provide stability and support to the joint. Additionally, washers can also help to prevent loosening of the fastener over time by creating friction between the bolt and the surface.

When an excess quantity of acetylene is mixed with oxygen for burning, it produces a carbruising flame. This flame is characterized by a highly reducing environment, which means it has a high concentration of unburned hydrocarbons. The carbruising flame is commonly used in welding and cutting applications as it provides a high temperature and concentrated heat source.

Foam is the best-suited extinguisher for oil or flammable liquid fires because it forms a blanket over the fuel, smothering the fire and preventing oxygen from reaching it. The foam also helps to cool down the fuel, reducing the temperature and preventing re-ignition. This type of extinguisher is effective for Class B fires, which involve flammable liquids such as gasoline, oil, and grease.

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Intercooling is the process of cooling the intake air before it enters the combustion chamber of an engine. This is done to achieve multiple benefits. Firstly, reducing the temperature of the intake air helps to lower the risk of knocking, which is the undesirable phenomenon of uncontrolled combustion. Secondly, cooler air is denser, resulting in increased volumetric efficiency, which means more air can be drawn into the engine for combustion. Therefore, intercooling helps to improve engine performance by reducing knocking and increasing volumetric efficiency, making "All of the above" the correct answer.

The ratio of the indicated thermal efficiency to the air standard efficiency is called the relative efficiency. This ratio compares the actual thermal efficiency of an engine to the ideal thermal efficiency that would be achieved if the engine operated on an air standard cycle. The relative efficiency provides a measure of how well the engine is performing relative to the idealized conditions.