Free Plant Design and Economics MCQs with Answers

• A. Nickel
• B. Cobalt
• C. Tungsten
• D. Chromium

Explanation: Cobalt raises the retentivity, or residual magnetism, of steel and is therefore used in permanent-magnet alloys.

• A. Mild steel
• B. Cast iron
• C. Refractory blocks
• D. Stainless steel

Explanation: A glass tank furnace must withstand very high temperatures and attack by molten glass, so its basin and walls are built from refractory…

• A. None of these
• B. Soften its surface
• C. Improve its reliability
• D. Harden its surface

Explanation: Nitriding diffuses nitrogen into the steel surface to form hard alloy nitrides, producing a hard, wear-resistant case.

• A. Galvanising
• B. Alloying
• C. Utensil manufacture
• D. Electrical industry

Explanation: Galvanising consumes the largest share of zinc because steel sheets, pipes and structural parts are coated with zinc to prevent corrosion.

• A. Simple hexagonal
• B. Body centred cubic
• C. Face centred cubic
• D. None of these

Explanation: Austenitic stainless steels have a face-centred cubic structure, which gives them high ductility and good formability.

• A. Rubber
• B. Monel
• C. Nickel
• D. Glass

Explanation: Deep-fermentation penicillin broths are handled in glass-lined steel vessels because the glass surface resists corrosion and contamination…

• A. Monel
• B. Duriron
• C. Hastelloy
• D. Inconel

Explanation: Monel is primarily an alloy of nickel and copper, valued for its strength and resistance to seawater and many corrosive chemicals.

• A. Inconel
• B. Babbitt metal
• C. Nimonics
• D. Hastelloys

Explanation: Babbitt metal is generally a tin- or lead-based bearing alloy containing antimony and copper, so it is not nickel-based.

• A. Is in the form of free Si
• B. Decreases the blow holes formation tendency in castings
• C. Indicates that steel is not deoxidised properly
• D. None of these

Explanation: Silicon is commonly added to steel as a deoxidiser, removing dissolved oxygen and thereby reducing carbon-monoxide blowholes during…

• A. High speed
• B. Molybdenum
• C. Silicon
• D. Tungsten

Explanation: Hypersil is a grain-oriented silicon steel used mainly for electrical transformer cores, where its magnetic properties reduce core losses.

• A. Glass, graphite, porcelain & stoneware
• B. Copper, cast iron & high silicon iron (14% Si)
• C. Rubber (butyl and hard), silicone rubber & Teflon
• D. Aluminium, mild steel, stainless steel, concrete & tin

Explanation: Sulfuric acid below about 50% concentration attacks aluminium, mild steel, many stainless steels, concrete, and tin, so these materials…

• A. Low temperature strength properties
• B. High strength to weight ratio
• C. Its ability to be cast, rolled, forged & stamped
• D. High strength and corrosion & oxidation-resistance at elevated temperature

Explanation: Aircraft benefit chiefly from aluminium alloys because they provide substantial strength with very low density.

• A. High ductility
• B. High malleability
• C. Its elastic limit very close to ultimate breaking strength
• D. Very high tensile strength

Explanation: Cast iron is brittle and undergoes very little plastic deformation, so its elastic limit lies close to its failure or ultimate breaking…

• A. Nylon-6
• B. Polypropylene
• C. Polyurethane
• D. Unsaturated polyester

Explanation: Unsaturated polyester resin is the most widely used matrix for reinforced plastics because it is economical, easy to process, and cures…

• A. Carbides
• B. Stainless steel
• C. Mild steel
• D. High carbon steel

Explanation: Wire-drawing dies must withstand severe wear and compressive stresses, so very hard carbides such as tungsten carbide are commonly used.

• A. Pack carburising
• B. Calorising
• C. Nitriding
• D. Cyaniding

Explanation: Pack carburising, nitriding, and cyaniding are case-hardening treatments that introduce carbon or nitrogen into the surface.

• A. Plastic limit
• B. Limiting load
• C. Elastic limit
• D. Breaking load

Explanation: The elastic limit is the greatest stress up to which a material returns completely to its original shape.

• A. Dilute H2SO4
• B. Dilute HNO3
• C. Dilute HCI
• D. Hydrofluoric acid

Explanation: Hydrofluoric acid attacks silica, the main constituent of ordinary glass, even though glass resists many dilute mineral acids.

• A. Plastic
• B. Steel
• C. Glass
• D. Rubber

Explanation: Elasticity in this comparison means resistance to elastic deformation, measured by Young's modulus, not the ability to stretch greatly.

• A. HCP
• B. BCC
• C. FCC
• D. Cubic

Explanation: FCC metals have many closely packed slip systems, allowing dislocations to move readily and producing high ductility.