mechanical engineering MCQs – Page 131

Practise multiple-choice questions from mechanical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

mechanical engineering Mcqs

1. compressors gas turbines and jet engines 2. theory of machines 3. nuclear power plants 4. engineering materials 5. strength of materials mechanical engineering 6. thermodynamics 7. heat transfer 8. i c engines 9. steam boilers engines nozzles and turbines 10. engineering mechanics 11. fluid mechanics mechanical engineering 12. production technology 13. machine design 14. hydraulic machines 15. workshop technology 16. refrigeration and air conditioning

2601. Railway rails are normally made of_______________?
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A. cast iron steel

B. tungsten steel

C. high carbon

D. alloy steel

E. mild steel

2602. Cast iron has_________________?
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A. none of the above

B. high ductility

C. high tensile strength

D. its elastic limit close to the ultimate breaking strength

E. all of the above

2603. Chromium in steel_________________?
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A. makes steel hard

B. refines grain size and produces less tendency to carburisation, improves corrosion and heat resistant properties

C. gives ductility, toughness, tensile strength and anticorrosion properties

D. improves wear resistance, cutting ability and toughness

E. improves cutting ability and reduces hardenability

2604. The correct sequence for descending order of machinability is _____________________?
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A. grey cast iron, wrought iron, low carbon steel

B. grey cast iron, low carbon steel, wrought iron

C. wrought iron,low carbon steel, grey cast iron

D. low carbon steel, grey cast iron, wrought iron

E. wrought iron, grey cast iron, low carbon steel

2605. Pure iron is the structure of_______________?
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A. pearlite

B. ferrite

C. ferrite and cementite

D. ferrite and pearlite

E. anstenite

2606. The molecules in a solid move______________?
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A. in a haphazard way

B. in circular motion

C. do not move

D. in a random manner

E. back and forth like tiny pendulums

2607. Which of the following alloys does not contain tin_________________?
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A. gun metal

B. phosphor bronze

C. white metal

D. fusible metal

E. solder admiralty

2608. Ductile cast iron___________________?
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A. is produced by annealing process. It is soft, tough and easily machined metal

B. is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material

C. none of the above

D. contains 1.7 to 3.5% carbon in free state and is obtained by the slow cooling of molten cast iron

E. is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable

2609. Tensile strength of steel can be safely in-creased by________________?
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A. adding carbon up to 0.83%

B. adding copper and carbon

C. adding carbon up to 6.3%

D. adding small quantities of copper

E. adding carbon up to 2.8%

2610. Perminvar alloy having constant permeability is an alloy of________________?
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A. copper, nickel and antimony

B. iron, zinc and bismuth