Free Plant Design and Economics MCQs with Answers

• A. Plastics
• B. Non-crystalline organic polymer
• C. Non-crystalline solids
• D. Crystalline solid

Explanation: Time-dependent viscoelasticity is especially characteristic of non-crystalline organic polymers because their long molecular chains slowly…

• A. Cast
• B. Stainless
• C. Carbon chrome
• D. Free carbon

Explanation: Ball-bearing races and balls are commonly made from hard carbon-chromium steel, which provides high hardness, wear resistance, and fatigue…

• A. Neither A. nor B.
• B. Corrosive
• C. Both A. & B.
• D. Abrasive

Explanation: Erosion is mechanical removal or deterioration caused by the abrasive action of a moving fluid, often containing suspended solids.

• A. Ductility
• B. Hardness
• C. Malleability
• D. None of these

Explanation: Malleable cast iron is valued because heat treatment converts its brittle structure into one with substantially improved ductility.

• A. Zinc
• B. Lead
• C. Mercury
• D. Tin

Explanation: An amalgam is an alloy in which mercury is one of the constituents, such as dental or sodium amalgams.

• A. Ceramic fibre blanket
• B. Slag wool
• C. Vermiculite
• D. Glass wool and 85% magnesia

Explanation: 85% magnesia is a traditional, widely used insulation for steam pipes because it has low heat conductivity and remains effective at…

• A. Extrusion
• B. Cold working
• C. Forging
• D. Electroforming

Explanation: Seamless steel pipes are commonly produced by piercing and extrusion-type hot-working operations, making extrusion the best option listed.

• A. Acid resistant, brittle and very hard
• B. All A., B. and C.
• C. Prone to breakage due to thermal expansion because of its very high co-efficient of thermal
• D. expansion
• E. High silicon iron

Explanation: Duriron is a high-silicon cast iron that resists acids but is very hard and brittle.

• A. Cast iron
• B. Pig iron
• C. Babbitt metal
• D. Steel

Explanation: Babbitt metal is used for bearing linings because it is soft enough to embed small dirt particles and conform to the shaft, while…

• A. All A., B. & C.
• B. Its hard and machinable
• C. Its brittle and malleable
• D. Its casting unsound

Explanation: Excess sulphur in pig iron promotes brittleness and causes hot-shortness, so castings may crack or become unsound.

• A. All A., B. & C.
• B. Very brittle
• C. Very hard
• D. More durable

Explanation: White cast iron contains carbon mainly as cementite, giving it very high hardness and brittleness compared with graphite-containing grey…

• A. Half
• B. One third
• C. One fifth
• D. One twelfth

Explanation: Wood has a tensile strength that is commonly estimated at roughly one-fifth of steel, although the actual value varies greatly with…

• A. Silicon
• B. Chromium
• C. Vanadium
• D. Nickel

Explanation: Vanadium has a very strong affinity for carbon and forms stable vanadium carbides in steel.

• A. None of these
• B. Chromium steel
• C. Molybdenum steel
• D. Silicon steel

Explanation: Silicon steel has low hysteresis and eddy-current losses, so it is used in transformer cores, motors, and generators.

• A. 0.3
• B. 0.5
• C. 0.8
• D. 2.5

Explanation: A low silicon content, about 0.8%, favours carbide formation and suppresses graphite, giving cast iron high hardness.

• A. Semi-conductor
• B. Metal/alloy
• C. Dielectric
• D. None of these

Explanation: Metals and alloys conduct mainly through free electrons, whose increased thermal motion at higher temperature increases scattering and…

• A. 18% nickel and 8% chromium
• B. 18% chromium and 8% molybdenum
• C. 18% chromium and 8% nickel
• D. 18% molybdenum and 8% chromium

Explanation: The first number in 18/8 stainless steel denotes approximately 18% chromium, while the second denotes approximately 8% nickel.

• A. Toughness
• B. Wear resistance
• C. Hardenability
• D. Both B. & C.

Explanation: High-speed steel must retain hardness at elevated cutting temperatures and resist abrasion, so high wear resistance and hardenability are…

• A. Nickel or copper
• B. Zinc or magnesium
• C. Bronze
• D. Brass

Explanation: Zinc and magnesium are more active than steel and therefore dissolve as sacrificial anodes, supplying cathodic protection to the buried…

• A. Dilute acidic
• B. Concentrated acidic
• C. Alkalis & alkaline
• D. None of these

Explanation: Wrought iron has good resistance to many alkaline solutions, making it suitable for alkalis and alkaline service.