Mechanical Engineering is part of Engineering and holds 2,078 questions with answers, free to read and with no account needed.
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Answer: A. improvement of casting characteristics
Adding silicon to aluminium significantly improves its molten fluidity and casting characteristics. Silicon-aluminium alloys reduce shrinkage defects and enhance mold-filling capabilities during pouring. Improved castabi...
Answer: C. 02
Orsat gas analysis apparatus measures volumetric percentages of combustion exhaust gas components. Chemical absorption pipettes within the Orsat apparatus contain specific reagents for individual gases. Alkaline pyrogall...
Answer: B. axial flow
Aeronautical jet engines require massive volumes of air ingested continuously at high flight speeds. Axial-flow compressors feature rows of rotating and stationary blades that accelerate and compress air parallel to the...
Answer: C. decreases fuel consumption
A boiler economizer uses waste exhaust flue gases to preheat incoming feedwater before it enters the drum. Preheating feedwater reduces the amount of thermal energy required from fuel combustion inside the boiler. Lower...
Answer: D. 10 : 90
Aluminium bronze alloys consist predominantly of copper combined with a smaller portion of aluminium. Standard metallurgical compositions place copper at roughly ninety percent of the alloy mass. Aluminium constitutes th...
Answer: B. supplied mounted on a single base
Packaged boilers are factory-assembled units designed for rapid installation and operation. All primary ancillary components are mounted together on a single structural steel base. Pre-assembly eliminates the need for co...
Answer: A. 50 : 20 : 20 : 10
Alnico alloy compositions are standardized with approximately fifty percent iron and balanced amounts of other metals. The exact formulation includes twenty percent nickel, twenty percent aluminium, and ten percent cobal...
Answer: B. less than 7
The logarithmic pH scale measures hydrogen ion concentration in aqueous chemical solutions. Neutral solutions maintain a pH value of exactly seven at standard temperature conditions. Acidic chemical solutions exhibit hig...
Answer: D. the energy is constant along a stream-line but may vary across streamlines
Bernoulli's principle is derived from applying the conservation of mechanical energy to flowing fluids. For steady, inviscid, and incompressible fluid motion, total mechanical energy remains constant along any individual...
Answer: C. extinguish fire if water level in the boiler falls below alarming limit
A fusible plug is constructed from a low melting point alloy threaded into the crown sheet of a boiler. If the boiler water level drops too low, the exposed plug overheats and melts rapidly. Melting allows steam to rush...
Answer: D. duralumin
Duralumin is a prominent copper-aluminium alloy known for significant precipitation hardening responses. Age-hardening in this alloy involves controlled precipitation of intermetallic hardening particles. Heat treatment...
Answer: B. F.C.C. crystal structure
Microscopic analysis of pure aluminium reveals a specific repeating atomic lattice arrangement. Face-centered cubic crystal structures feature atoms at each corner and center of cube faces. Aluminium atoms pack closely t...
Answer: C. one of the best known age and precipitation-hardening systems
Alloying copper with aluminium creates a metallic combination that responds remarkably well to heat treatment processes. Precipitation hardening significantly increases the mechanical strength and hardness of these speci...
Answer: D. super heated steam
High-pressure locomotive boilers generate steam that is heated above saturation temperatures for efficiency. Escaping fluid from a seeping pressure relief valve consists of high-energy superheated steam. Superheated stea...
Answer: C. 218 kg/cm2 abs and 373°C
Supercritical steam generators operate above the thermodynamic critical pressure of water, which is approximately 218 atm (218 kg/cm² abs) and 373°C.
