mechanical engineering MCQs – Page 132

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 Review each marked answer and report any item that may be outdated or unclear.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

2621. Paramagnetic alpha iron changes to gamma iron at_______________?
0

A. none of the above

B. 770C

C. 1539C

D. 1440C

E. 910C

2622. Hardness of martensite is about___________________?
0

A. RC 48

B. RC 80

C. RC 65

D. RC 32

E. RC 57

2623. Inconel is an alloy of___________________?
0

A. nickel, chromium

B. nickel, chromium and iron

C. nickel, zinc

D. nickel, lead

E. nickel, copper

2624. A cold chisel is made of_______________?
0

A. mild steel

B. german silver

C. H.S.S.

D. high carbon

E. cast iron

2625. Muntz metal contains copper and zinc in the ratio of________________?
0

A. 40 : 60

B. 50:50:00

C. 60 : 40

D. 0.888888889

E. 80:20:00

2626. Addition of manganese to aluminium results in__________________?
0

A. improvement of casting characteristics

B. none of the above

C. improving machinability

D. improvement of corrosion resistance

E. one of the best known age and precipitation-hardening systems

2627. In nodular iron, graphite is in the form of_____________________?
0

A. spheroids

B. cementite

C. free carbon

D. flakes

E. nodular aggregates of graphite

2628. Which is false statement about normalizing. Normalizing is done to _________________?
0

A. refine grain structure

B. reduce segregation in casting

C. induce stresses-

D. relieve internal stresses

E. improve mechanical properties

2629. Elinvar, an alloy used in precision instruments, hair springs for watches, etc. contains the following element as principal alloying element__________________?
0

A. aluminium

B. iron

C. copper

D. zinc

E. nickel

2630. Process of austempering results in__________________?
0

A. carburised structure

B. formation of bainite structure

C. lamellar layers of carbide distributed throughout the structure

D. relieving of stresses throughout a component

E. martenistic structure

2631. The surface hardness of the following order is achieved by nitriding operation__________________?
0

A. 250 VPN

B. 1500 VPN

C. 2000 VPN

D. 600 VPN

E. 1000 to 1100 VPN

2632. Corrosion resistance of steel is increased by adding__________________?
0

A. tungsten and sulfur

B. none of the above

C. nickel and molybdenum

D. chromium and nickel

E. aluminium and zinc

2633. The crystal structure of gamma iron is_________________?
0

A. orthorhombic crystal

B. face centred cubic

C. cubic structure

D. hexagonal close packed

E. body centred cubic

2634. The correct composition of Babbit metal is__________________?
0

A. 90% Sn, 2% Cu, 4% Sb, 2% Bi, 2% Mg

B. 82% Sn, 4% Cu, 8% Sb, 3% Al, 3% Mg

C. 87% Sn, 4% Cu, 8% Sb, 1% Al

D. none of the above

E. 87.75% Sn, 4% Cu, 8% Sb, 0.25% Bi

2635. The presence of sulphur in pig iron makes__________________?
0

A. it hard

B. it brittle

C. the casting unsound

D. it easily machinable

E. increases the fluidity

2636. Which one of the following metals would work-harden more quickly than the others__________________?
0

A. silver

B. brass

C. lead

D. copper

E. aluminium

2637. Melting point of iron is__________________?
0

A. 1539C

B. 1601C

C. 1489C

D. 1131C

E. 1712C

2638. Which of the following alloys does not have copper as one of the constituents________________?
0

A. constantan

B. delta metal

C. nichrome

D. monel metal

E. silicon bronze

2639. Which of the following element results in presence of free graphite in C.I_________________?
0

A. sulphur

B. carbon

C. silicon

D. phosphorous

E. manganese

2640. Chilled cast iron has____________________?
0

A. none of the above is true

B. a low percentage of graphite

C. no graphite

D. a very high percentage of graphite

E. graphite as its basic constituent of composition

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