NTPC Mechanical Engineering Previous Papers

Please provide me question paper for NTPC Mechanical Engineering examination soon ?

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Here I am giving you question paper for NTPC Mechanical Engineering examination.

1 An ice block submerged in the water, if the ice melts level of water (increase,decrease,remains same,none)
2 Simply supported beam with w point load at the middle, max. bending moment?(wl/4)
3 Simply supported beam with UDL ,max.deflection (wl4/384EI)
4 Cantilevel beam point load at tip,max.bending momemt comes at (end)
5 When bearing life L10 represents (bearings 10%survive,bearings 10% fails, none )

6 For welding high carbon steels which type of flame is used (oxidizing,carburizing,neutral,none)

7. Arrange the following cutting tools in decreasing order of machining hardness…Ceramics

8. When P1 and P2 are the loads acting on bearings with life L1 and L2 then L1/L2=?
L1/L2={P2/P1}10/3

9.Product simplification does not mean??
Product characterization

10 Which of the following process has the most scope in manufacturing?
CAD/CAM, CAM, CIM, All the above.

11. Concurrent engineering means?
(Manufacturing, designing, both,none)

12. Which manufacturing process yields higher output and increases worker productivity-
(process layout,line+process,functional layout)

13. 18-4-1 represents-, Tungsten-Cr-Vn

14 For which material is negative allowance provided-(Graphite,steel,bronze,cast iron)

15. What is the recrystallisation temperature of tin- (60,300,1000,none)

16. What is the purpose of borax in soldering-

17. Top gates are provided in which type of casting-(Shallow casting,simple,complex,none)
18. Which statement is true regarding simple gear trains-(i/p and o/p shafts r fixed, each shaft has 2 gears, i/p & o/p shafts r moving)

19. What is the purpose of normalizing- (Refining of grain structure)

20. As the grain size is decreased-(Hardness increases,corrosion resistance decreases,both)

21. Isothermal gas is filled in a vessel at a pressure P and temperature T then considering the compressible forces as the height increases pressure ??(linearly increases linearly decreases exponentially increase )

22. A bottle is filled with water and air and is tied to a string and is rotated in horizontal direction. Then in which direction will air bubble travel?
(bottom,neck,uniformly spread)

23. A empty bottle(in vaccum) filled with a gas at temp T and press P when the pressure of bottle reaches P temperature of the gas is _? (T,T/K,TK)

24. Bearing somerfield number _ with load on bearing?
(increases,decreases,no change)

25. Critical radius for a sphere is-(2k/h)
26. Critical radius exist for_ (spherical,cylindrical,both,slab)
27. Convectional resistance/internal resistance is called (biot number)
28. Nusselt no. is? (hl/k)
29. EOQ=?

30 Which statement is true regarding critical path method? (i only one critical path exists for a network, more than one with same duration,)

31. Shipment cost,inspection cost,storage cost comes under_ (carrying cost ,holding cost,)

32. Ischronous governers sensitivity is- (zero,infinite)

33. self energized brakes are-(friction moment acts in the direction of application of force,opposite to the direction of force, does not need a force to act ,)

34 The ratio of heat capacities for evaporator and condenser is_ (Zero,infinity)

35. when steam and air mixture with partial pressure 0.06 and 0.07 enters a condenser what is the condenser pressure? (0.06,0.07,0.53,0.03)

36. In pulverized burning of coal heat transfer from boiler to water occurs through_( predominant radiation, convection, conduction, conduction+convection)

37. Rankine cycle efficiency for same parameters increases mostly with_(reheat, regeneration, super heating )

38. Ericson cycle with all reversible processes assume_(carnot cycle,stirling,brayton

39. Air delivery tank at outlet of reciprocating compressor is provided for_ (provide constant pressure, avoid cavitation, )

40. High speed centrifugal pump has _?
(vanes faces in forward direction side,backward,radial vanes)

41. Thermal efficiency in decreasing order_?
(Otto cycle>dual cycle>diesel cycle)

42. When a 1000 K body comes in contact with atmosphere at 300K a loss of 9000 KJ heat is transferred. The net available energy transferred is_
43. When entropy of a system increases_?
(unavailable energy increases )

44. Rolling is a process widely used for_?

(I section,tubes)

45. Tool nomenclature_?

46. In francis turbine movement of steam?

47. For low power consumption _?
(rake angle should be increased / decreased, nose angle increased/ decreased)

47. Continuous chips occur in_?
(High speeds,low speeds,both,none)

48. Primary forces in a reciprocating engine_?
(fully balanced, partially balanced, completely unbalanced, none)

49. In proximate analysis pyrogallol is used for analysis of which element_?
(nitrogen,oxygen)

50. Sulphur content in fuel greatly affects_?
(corrosion)

NTPC mechanical paper
1.In a throttling process, the pressure of an ideal gas reduces by 50 %. If Cp and Cv are the heat capacities at constant pressure and constant volume, respectively (ϒ=Cp/Cv), the specific volume will change by a factor of
(A) 2
(B) 21/ϒ
(C) 2(ϒ-1)/ϒ
(D) 0.5

Ans:A




2. If the temperature of saturated water is increased infinitesimally at constant entropy, the resulting state of water will be
(A) Liquid
(B) Liquid – vapor coexistence
(C) Saturated vapor
(D) Solid
Ans:A




3. For an exothermic reversible reaction, which one of the following correctly describes the dependence of the equilibrium constant ( K ) with temperature (T ) and pressure ( P ) ?

(A) K is independent of T and P
(B) K increases with an increase in T and P
(C) K increases with T and decreases with P
(D) K decreases with an increase in T and is independent of P

Ans




4. Water is flowing under laminar conditions in a pipe of length L . If the diameter of the pipe is doubled, for a constant volumetric flow rate, the pressure drop across the pipe

(A) decreases 2 times
(B) decreases 16 times
(C) increases 2 times
(D) increases 16 times

Ans:B


5. The local velocity of a fluid along a streamline can be measured by

(A) Pitot tube
(B) Venturi meter
(C) Rotameter
(D) Orifice meter

Ans:A




6. For heat transfer across a solid-fluid interface, which one of the following statements is NOT true when the Biot number is very small compared to 1?

(A) Conduction resistance in the solid is very small compared to convection resistance in the fluid
(B) Temperature profile within the solid is nearly uniform
(C) Temperature drop in the fluid is significant
(D) Temperature drop in the solid is significant

Ans




7. In the McCabe-Thiele diagram, if the x -coordinate of the point of intersection of the q -line and the vapor-liquid equilibrium curve is greater than the x -coordinate of the feed point, then the quality of the feed is

(A) super-heated vapor
(B) liquid below bubble point
(C) saturated vapor
(D) saturated liquid

Ans:B




8. For which of the following combinations, does the absorption operation become gas-film controlled?

P. The solubility of gas in the liquid is very high
Q. The solubility of gas in the liquid is very low
R. The liquid-side mass transfer coefficient is much higher than the gas-side mass transfer coefficient
S. The liquid-side mass transfer coefficient is much lower than the gas-side mass transfer coefficient

(A) P & Q
(B) P & R
(C) P & S
(D) Q & R

Ans:B




9. The half-life of an nth order reaction in a batch reactor depends on

(A) only the rate constant
(B) only the rate constant and the order of the reaction
(C) only the rate constant and the initial reactant concentration
(D) the rate constant, initial reactant concentration, and the order of the reaction

Ans




10. In petroleum refining, catalytic reforming is used to convert

(A) Paraffins and naphthenes to aromatics
(B) Paraffins to hydrogen and carbon monoxide
(C) Gas oil to diesel and gasoline
(D) Light olefins to gasoline

Ans:A




11. T he final boiling points of gasoline, diesel, atmospheric gas oil (AGO) and lubricating oils vary as

(A) gasoline > diesel > AGO > lubricating oils
(B) lubricating oils > AGO > diesel > gasoline
(C) AGO > lubricating oils > diesel > gasoline
(D) lubricating oils > diesel > AGO > gasoline

Ans:B




12. The main unit processes used for the production of hydrogen from natural gas are steam reforming (SR), pressure swing adsorption (PSA), low temperature water gas shift reaction (LT WGS) and high temperature water gas shift reaction (HT WGS). The correct sequence of these in the plant is

(A) SR; LT WGS; HT WGS; PSA
(B) PSA; SR; LT WGS; HT WGS
(C) SR; HT WGS; LT WGS; PSA
(D) PSA; HT WGS; LT WGS; SR

Ans:C




13. A thermometer initially at 100°C is dipped at t = 0 into an oil bath, maintained at 150°C. If the recorded temperature is 130°C after 1 minute, then the time constant of thermometer (in min) is

(A) 1.98
(B) 1.35
(C) 1.26
(D) 1.09

Ans




14. The Bode stability criterion is applicable when

(A) Gain and phase curves decrease continuously with frequency
(B) Gain curve increases and phase curve decreases with frequency
(C) Gain curve and phase curve both increase with frequency
(D) Gain curve decreases and phase curve increases with frequency

Ans:A




15. An equimolar mixture of A and B (A being more volatile) is flash distilled continuously at a feed rate of 100 kmol/h, such that the liquid product contains 40 mol % of A. If the relative volatility is 6, then the vapor product, in kmol/h, is

(A) 10
(B) 20
(C) 25
(D) 45

Ans:C