Free Plant Design and Economics MCQs with Answers
803 Plant Design and Economics MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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781. The process of removal of scale formed during hot rolling of steel is termed as_________________?
- A. Descaling
- B. Shot blasting
- C. Pickling
- D. Skimming
Explanation: Pickling removes oxide scale from hot-rolled steel by chemical action, commonly using an acid bath.
Correct answer: Pickling- A. Steam jet arrangement
- B. Induced draught fan
- C. Forced draught fan
- D. Chimney
Explanation: Locomotive boilers commonly use a steam jet arrangement to create draught: exhaust steam expands through a nozzle and entrains combustion…
Correct answer: Steam jet arrangement- A. Aluminium
- B. Stainless steel
- C. Brass
- D. Copper
Explanation: Stainless steel generally has a lower scrap value than aluminium, brass, or copper because its valuable alloy constituents are diluted by…
Correct answer: Stainless steel- A. Creep resistance
- B. Malleability
- C. Stiffness
- D. Tensile strength
Explanation: Young's modulus is the ratio of elastic stress to elastic strain and indicates how strongly a material resists elastic deformation.
Correct answer: Stiffness- A. Machinability
- B. Density
- C. Plastic deformation
- D. Strength
Explanation: Compared with metals, plastics generally have lower mechanical strength and stiffness, although their low density and corrosion resistance…
Correct answer: Strength- A. Copper
- B. Graphite
- C. Stainless steel
- D. Steel
Explanation: Copper is used for resistance-welding electrodes because its high electrical and thermal conductivity limits electrode heating while…
Correct answer: Copper787. Which of the following is not a characteristic observed in material failure by fatigue fracture ?
- A. Plastic deformation of material does not occur
- B. Initiation of crack from below the surface does not occur
- C. Initiation of crack occurs on the surface of the machine part
- D. Presence of both rough & smooth zone with conchoidal markings in smooth zone of the
Explanation: Fatigue cracks commonly start at the surface, but subsurface initiation can occur at inclusions or other internal defects.
Correct answer: Initiation of crack from below the surface does not occur788. The bolt is subjected to _______________ when the nut is tightened by putting the washer beneath it?
- A. Bending & tension
- B. Shear
- C. Compression
- D. Tension
Explanation: Tightening the nut stretches the bolt and produces tensile preload in it, while the clamped parts experience compression.
Correct answer: Tension- A. Soft iron
- B. Copper
- C. Mild steel
- D. Stainless steel
Explanation: Soft iron binding wire is commonly used to hold soldered parts firmly during heating and cooling.
Correct answer: Soft iron- A. Induction motor
- B. Electrostatic precipitator
- C. Fast breeder reactor
- D. Magneto hydrodynamic generator (MHD)
Explanation: An electrostatic precipitator creates corona discharge to charge suspended dust particles, which are then attracted to oppositely charged…
Correct answer: Electrostatic precipitator791. Which of the following is normally not found in both the S.I. (petrol) & C.I. (diesel) engines ?
- A. Air filter
- B. Exhaust silencer
- C. Fuel injector
- D. Battery
Explanation: In the conventional comparison, a diesel engine requires a fuel injector, whereas a petrol SI engine traditionally uses a carburettor.
Correct answer: Fuel injector- A. Nipple
- B. Bell and spigot
- C. Union
- D. Socket
Explanation: A socket joint is commonly used for joining pipes carrying water at low pressure, with one pipe end fitting into the socket of another.
Correct answer: Socket- A. Yield
- B. Compressive
- C. Tensile
- D. Bearing
Explanation: The factor of safety compares the limiting strength, commonly yield stress for ductile materials, with the allowable or working stress.
Correct answer: Yield- A. Decarburising
- B. Alloying with cobalt
- C. Purification
- D. Alternate heating & cooling
Explanation: Adding cobalt to iron improves its magnetic properties, including magnetic permeability, because cobalt supports strong ferromagnetism.
Correct answer: Alloying with cobalt- A. Cermets
- B. Stellite
- C. Tungsten carbide
- D. High speed steel
Explanation: Broaching involves many cutting teeth and substantial wear, so broaches are commonly manufactured from high-speed steel, which retains…
Correct answer: High speed steel- A. Notched bar impact
- B. Fatigue
- C. Tensile
- D. Hardness
Explanation: Temper brittleness reduces toughness, especially in a notched specimen, so it is revealed effectively by a notched-bar impact test.
Correct answer: Notched bar impact- A. Titanium
- B. Copper
- C. Aluminium
- D. Stainless steel
Explanation: Titanium is highly resistant to chloride-rich brine and has excellent resistance to pitting and crevice corrosion, making it suitable for…
Correct answer: Titanium- A. Cathodic protection
- B. Anodic protection
- C. Usage of largest possible anodic area
- D. Any one of these
Explanation: Cathodic protection makes the metal surface a cathode, while using a large anodic area reduces the anodic current density.
Correct answer: Anodic protection- A. 1
- B. 4.0
- C. 8
- D. 14
Explanation: Electrical silicon steel commonly contains about 3 to 4.5% silicon, with approximately 4% being the standard figure.
Correct answer: 4.0- A. Polystyrene
- B. Teflon (PTFE)
- C. Bakelite (phenol formaldehyde)
- D. Perspex (PMMA)
Explanation: Perspex is polymethyl methacrylate (PMMA), a transparent, lightweight and impact-resistant material suitable for aircraft window panes.
Correct answer: Perspex (PMMA)