MECHANICAL ENGINEERING- PAGE 14
Mechanical Engineering MCQs- Page 14
1:-The primary function of a surge tank is to
A:-Store excess water from tail race B:-Increase power output from the turbine
C:-Act as container for surge arrester D:-Prevent pressure wave due to water hammer in penstock
Ans: D
2:-A universal joint allow the propeller shaft to
A:-bend sideways B:-change length
C:-transfer torque at an angle D:-change inclination
Ans: C
3:-The function of an economizer in a steam power plant is to
A:-increase the temperature of supply air B:-increase the temperature of feed water
C:-condense the exhaust steam from the turbine D:-preheat the fuel
Ans: B
4:-The compression ignition engines are governed by
A:-Hit and miss governing B:-Quantity governing
C:-Quality governing D:-Combination of (2) and (3)
Ans: C
5:-The speed ratio between crankshaft and camshaft is
A:-2 : 1 B:-4 : 1 C:-1 : 2 D:-1 : 4
Ans: A
6:-The minimum depth for all foundations below the natural ground level is
A:-500 mm B:-1200 mm C:-250 mm D:-100 mm
Ans: A
7:-A projected stone in masonry wall provided to joist or truss is known as
A:-cornice B:-corbel C:-coping D:-cramp
Ans: B
8:-Natural error in levelling is caused due to
A:-Wind vibration B:-Atmospheric refraction C:-Temperature variation D:-All the above
Ans: D
9:-Find the time taken for a sinusoidal alternating current of maximum value 20A to reach 15A for the first time, after being instantaneously zero, the supply frequency being 40 Hz
A:-2.35 ms B:-3.37 ms C:-4.44 ms D:-1.23 ms
Ans: B
10:-Two coils having equal resistance but different inductances are connected in series. The time constant of the series combination is A:-Sum of the time constant of individual coils B:-Average of the time constant of individual coils
C:-Geometrical mean of the time constant of individual coils D:-Product of the time constant of individual coils
Ans: B
11:-A network contains linear resistor and ideal voltage sources. If value of all the resistors are doubled, then voltage across each resistor is
A:-Halved B:-Doubled C:-Not changed D:-Increase 4 times
Ans: C
12:-GaAs LED's emit radiation in the
A:-Ultraviolet region B:-Blue-green region of visible region
C:-Orange-red range of visible region D:-Infra red region
Ans: D
13:-The function of Network and Switching Subsystem (NSS) in GSM is to
A:-Provide and manage radio transmission path between the mobile stations and the Mobile Switching Centre (MSC)
B:-Manage the switching functions of the system and allows the Mobile Switching Centre (MSC) to communicate with other networks C:-Supports the operation and maintenance of GSM
D:-Manage the radio interface between the mobile station and all other subsystems of GSM
Ans: B
14. Nitrogen at 25 atm and 37°C is contained in a cylinder of volume 10 m3. The cylinder is placed in a large container of 150 times the cylinder volume. The container is perfectly evacuated and insulated. The nitrogen gas is allowed to discharge and fill the container. Calculate the final pressure after the system has reached equilibrium.
(A) 0.267 atm (B) 0.322 atm (C) 0.259 atm (D) 0.167 atm
Ans: D
15. Determine the final stored energy of a mass of water that has an initial stored energy, E= 200kJ, and then undergo a process during which 10kJ of work is done on the water and 3kJ of heat is removed from it.
(A) 33 kJ (B) 45 kJ (C) 27 kJ (D) 60 kJ
Ans: C
16. Compute the power required to drive a reversible refrigerator if 100kJ/min is absorbed from the cold region and the isothermal process occurs at 40°C and -5°C.
(A) 17 kJ/min (B) 35kJ/min (C) 51kJ/min (D) 25kJ/min
Ans: A
17. A new temperature scale say °M, the boiling and freezing point of water at 1 atm are 100°M and 300°M respectively. Correlate this scale with Centigrade scale. The reading of 0°M on centigrade scale is
(A) 0°C (B) 50°C (C) 100°C (D) 150°C
Ans: D
18. An ideal gas at 27°C is heated at constant pressure till the volume becomes three times. The temperature of the gas will then be
(A) 81°C (B) 900°C (C) 627°C (D) 927°C
Ans: C
19. During steady flow compression process of a gas with mass flow rate of 2 kg/s, increase in specific enthalpy is 15kJ/kg and decrease in kinetic energy is 2kJ/kg. The rate of heat rejection to the environment is 3 kW. The power needed to drive the compressor is
(A) 23kW (B) 26kW (C) 29kW (D) 37 kW
Ans: C
20. For steady flow through an insulated horizontal constant diameter pipe, which property remains constant?
(A) Enthalpy (B) Internal energy (C) Entropy (D) Volume
Ans: A
21. For a heat engine operating on the Carnot cycle, the work output is ¼ of the heat transferred to the sink. The efficiency of the engine is (A) 20% (B) 33. 3% (C) 40% (D) 50%
Ans: A
22. A system of 100 kg mass undergoes a process in which its specific entropy increases from 0.3kJ/kg K to 0.4kJ/kg K. At the same time, the entropy of the surrounding decreases from 80kJ/K to 75kJ/K . The process is
(A) Reversible and isothermal (B) Irreversible (C) Reversible only (D) Isothermal only
Ans: B
23. Starting from the same initial conditions, an ideal gas expands from volume V1 to V2 in three different ways, the work done by the gas is W1 if the process is purely isothermal, W2 if purely isobaric and W3 if purely adiabatic, then
(A) W2 > W1 > W3 (B) W2> W3> W1 (C) W1 > W2 > W3 (D) W1 > W3 > W2
Ans: A
24. A house refrigerator with its door open is switched on in a closed room. The air in the room is
(A) Cooled (B) Remains at same temperature (C) Heated (D) Heated or cooled depending on atmospheric pressure
Ans: C
25. A steel ball of mass 1 Kg and specific heat 0.4 KJ/Kg is at a temperature of 60°C. It is dropped into 1 Kg water at 20°C. The final steady state temperature of water is
(A) 23.5°C (B) 30°C (C) 35°C (D) 40°C
Ans: A
26. A gas having a negative Joule-Thomson effect (µ<0), when throttled will
(A) Become cooler
(B) Become warmer
(C) Remain in the same temperature
(D) Become Cooler or warmer depending upon the type of gas
Ans: B
27. The difference between two specific heats Cp-Cv=R/J. This relation is valid for
(A) Any gas (B) Perfect gas (C) Ideal gas (D) Pure gas
Ans: B
28. Three metal walls of the same cross sectional area having thermal conductivities in the ratio 1:2:4 transfer heat at the rate of 6000KJ/hr. For the same wall thickness, the temperature drops will be in the ratio
(A) 1:2:4 (B) 1:1/2:1/4 (C) 1/4 :1/2:1 (D) 1:1:1
Ans: A
29. A grey body is defined such that
(A) Monochromatic emissivity of the body is independent of temperature
(B) Monochromatic emissivity of the body is dependent on temperature
(C) Monochromatic emissivity of the body is independent of wave length
(D) Monochromatic emissivity of the body is dependent on wave length
Ans: C
30. A flat plate of length 1 m and width 50 cm is placed in an air stream at 30°C is blowing parallel to it. The convective heat transfer coefficient is 30 W/(m2K). The heat transfer if the plate is maintained at a temperature of 400°C is__________
(A) 5.55 kW (B) 4.05 kW (C) 55.5 kW (D) 6 Kw
Ans: A
31. It is required to insulate a kitchen oven with cork board (K=0.043 W/(mK) so that the heat losses from the oven does not exceed 400 W/m2 when the inner surface of the oven is at 225°C and the outer surface of the oven is at 40 °C. The thickness of insulation required is nearly
(A) 1cm (B) 2cm (C) 3cm (D) 4cm
Ans: B
32. A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same heat loss and temperature drop, this can be replaced by a layer of diatomite earth of conductivity 0.14W/mK and thickness
(A) 0.05m (B) 0.1m (C) 0.2m (D) 0.5m
Ans: B
33. The maximum net specific work obtained in an ideal Brayton cycle for max temperature 900 K and minimum temperature 400 K is given by
(A) 100Cp (B) 500Cp (C) 800Cp (D) 700Cp
Ans: A
34. An open cycle pressure gas turbine uses a fuel of calorific value 40000kJ/kg with air fuel ratio of 80:1 and develops a net output of 80kJ/kg of air. The thermal efficiency of cycle is
(A) 12% (B) 16% (C) 20% (D) 18%
Ans: B
35. The surface imperfection which separates crystal of different orientation in a poly crystalline aggregate is called
(A) Edge dislocation (B) Stacking fault (C) Grain boundary (D) Screw dislocation
Ans: C
36. The latent heat load in an auditorium is 25% of sensible heat load. The value of sensible heat factor is
(A) 0.3 (B) 0.5 (C) 0.8 (D) 1.0
Ans: C
37. In psychometric charts, what does a vertical downward line represent?
(A) Sensible cooling process (B) Adiabatic saturation process (C) Humidification process (D) Dehumidification process
Ans: D
38. In milk chilling plants, the usual secondary refrigerant is
(A) Ammonia solution (B) Sodium silicate (C) Glycol (D) Brine
Ans: D
39. Which of the non-dimensional number relates the thermal boundary layer and hydrodynamic boundary layer?
(A) Rayleigh number (B) Peclet number (C) Grashoff number (D) Prandtl number
Ans: D
40. In two stage gas turbine plants, with intercooling and reheating
(A) Both work ratio and thermal efficiency increase (B) Work ratio increases but thermal efficiency decreases
(C) Thermal efficiency increases but work ratio decreases (D) Both work ratio and thermal efficiency decrease
Ans: B
41. A plane wall is 25 cm thick with an area of 1 m2, and has a thermal conductivity of 0.5 W/mK. If a temperature difference of 60°C is imposed across it, what is the heat flow?
(A) 120W (B) 140W (C) 160W (D) 180W
Ans: A
42. A solid sphere and a hollow sphere of the same material and size are heated to the same temperature and allowed to cool in the same surroundings. If the temperature difference between the body and that of the surroundings is T, then
(A) Both spheres will cool at the same rate for small values of T
(B) Both spheres will cool at the same rate for high values of T
(C) The hollow sphere will cool at a faster rate for all the values of T
(D) The solid sphere will cool at a faster rate for all the values of T
Ans: C
43. A steel steam pipe 10 cm inner diameter and 11 cm outer diameter is covered with insulation having the thermal conductivity of 1 W/mK. If the convective heat transfer coefficient between the surface of insulation and the surrounding air is 8 W / m2 K, then critical radius of insulation is
(A) 10 cm (B) 11 cm (C) 12.5 cm (D) 15 cm
Ans: C
44. Which one of the following is correct? The effectiveness of a fin will be maximum in an environment with
(A) Free convection (B) Forced convection (C) Radiation (D) Convection and radiation
Ans: A
45. The flash chamber in a single stage simple vapour compression system
(A) increases the refrigerating effect (B) decreases the refrigerating effect
(C) increases the work of compression (D) has no effect on refrigerating effects
Ans: D
46. Which one of the following statements is correct? The non-dimensional parameter known as Stanton number (St) is used in
(A) Forced convection heat transfer over flat plate
(B) Condensation heat transfer with laminar film layer
(C) Natural convection heat transfer over flat plate
(D) Unsteady heat transfer from bodies in which internal temperature gradients cannot be neglected
Ans: A
47. Which substance has minimum value of thermal conductivity
(A) Air (B) Water (C) Plastic (D) Rubber
Ans: A
48. What is hunting of thermostatic expansion valve?
(A) A variation of evaporative load with degree of superheat (B) A variation of pressure of the evaporator with variation of load
(C) Alternate overfeeding and starving of refrigerant flow in the evaporator (D) This is used in connecting with expansion valve
Ans: C
49. In VCRS plant, the refrigerant leaves the compressor and evaporator with enthalpy of 205kJ/ kg and 177kJ/kg respectively. Enthalpy of leaving the condenser is 105kJ/kg . If the mass flow rate of the refrigerant is 0.2kg/sec, then the refrigerant effect will be
(A) 12.2kW (B) 14.4kW (C) 16.4kW (D) 20.2Kw
Ans: B
50. Ozone depletion by CFC occurs by breakdown of
(A) Chlorine atoms from refrigerant by UV radiation and reaction with Ozone in troposphere
(B) Fluorine atoms from refrigerant by UV radiation and reaction with Ozone in troposphere
(C) Chlorine atoms from refrigerant by UV radiation and reaction with Ozone in stratosphere
(D) Fluorine atoms from refrigerant by UV radiation and reaction with Ozone in stratosphere
Ans: C
51. Maximum possible COP of a solar absorption refrigeration system with generator temperature of 360K, absorber temperature of 300K, condenser temperature of 300K and evaporator temperature of 270K is
(A) 9 (B) 6 (C) 3 (D) 1.5
Ans: D
52. Two air streams with mass flow rates of 36 kg/min and 14 kg/min with respective enthalpies of 36 kJ/kg and 50kJ/kg are mixed. The enthalpy of mixture is nearly
(A) 64kJ/kg (B) 55kJ/kg (C) 46kJ/kg (D) 40kJ/kg
Ans: D
A:-Store excess water from tail race B:-Increase power output from the turbine
C:-Act as container for surge arrester D:-Prevent pressure wave due to water hammer in penstock
Ans: D
2:-A universal joint allow the propeller shaft to
A:-bend sideways B:-change length
C:-transfer torque at an angle D:-change inclination
Ans: C
3:-The function of an economizer in a steam power plant is to
A:-increase the temperature of supply air B:-increase the temperature of feed water
C:-condense the exhaust steam from the turbine D:-preheat the fuel
Ans: B
4:-The compression ignition engines are governed by
A:-Hit and miss governing B:-Quantity governing
C:-Quality governing D:-Combination of (2) and (3)
Ans: C
5:-The speed ratio between crankshaft and camshaft is
A:-2 : 1 B:-4 : 1 C:-1 : 2 D:-1 : 4
Ans: A
6:-The minimum depth for all foundations below the natural ground level is
A:-500 mm B:-1200 mm C:-250 mm D:-100 mm
Ans: A
7:-A projected stone in masonry wall provided to joist or truss is known as
A:-cornice B:-corbel C:-coping D:-cramp
Ans: B
8:-Natural error in levelling is caused due to
A:-Wind vibration B:-Atmospheric refraction C:-Temperature variation D:-All the above
Ans: D
9:-Find the time taken for a sinusoidal alternating current of maximum value 20A to reach 15A for the first time, after being instantaneously zero, the supply frequency being 40 Hz
A:-2.35 ms B:-3.37 ms C:-4.44 ms D:-1.23 ms
Ans: B
10:-Two coils having equal resistance but different inductances are connected in series. The time constant of the series combination is A:-Sum of the time constant of individual coils B:-Average of the time constant of individual coils
C:-Geometrical mean of the time constant of individual coils D:-Product of the time constant of individual coils
Ans: B
11:-A network contains linear resistor and ideal voltage sources. If value of all the resistors are doubled, then voltage across each resistor is
A:-Halved B:-Doubled C:-Not changed D:-Increase 4 times
Ans: C
12:-GaAs LED's emit radiation in the
A:-Ultraviolet region B:-Blue-green region of visible region
C:-Orange-red range of visible region D:-Infra red region
Ans: D
13:-The function of Network and Switching Subsystem (NSS) in GSM is to
A:-Provide and manage radio transmission path between the mobile stations and the Mobile Switching Centre (MSC)
B:-Manage the switching functions of the system and allows the Mobile Switching Centre (MSC) to communicate with other networks C:-Supports the operation and maintenance of GSM
D:-Manage the radio interface between the mobile station and all other subsystems of GSM
Ans: B
14. Nitrogen at 25 atm and 37°C is contained in a cylinder of volume 10 m3. The cylinder is placed in a large container of 150 times the cylinder volume. The container is perfectly evacuated and insulated. The nitrogen gas is allowed to discharge and fill the container. Calculate the final pressure after the system has reached equilibrium.
(A) 0.267 atm (B) 0.322 atm (C) 0.259 atm (D) 0.167 atm
Ans: D
15. Determine the final stored energy of a mass of water that has an initial stored energy, E= 200kJ, and then undergo a process during which 10kJ of work is done on the water and 3kJ of heat is removed from it.
(A) 33 kJ (B) 45 kJ (C) 27 kJ (D) 60 kJ
Ans: C
16. Compute the power required to drive a reversible refrigerator if 100kJ/min is absorbed from the cold region and the isothermal process occurs at 40°C and -5°C.
(A) 17 kJ/min (B) 35kJ/min (C) 51kJ/min (D) 25kJ/min
Ans: A
17. A new temperature scale say °M, the boiling and freezing point of water at 1 atm are 100°M and 300°M respectively. Correlate this scale with Centigrade scale. The reading of 0°M on centigrade scale is
(A) 0°C (B) 50°C (C) 100°C (D) 150°C
Ans: D
18. An ideal gas at 27°C is heated at constant pressure till the volume becomes three times. The temperature of the gas will then be
(A) 81°C (B) 900°C (C) 627°C (D) 927°C
Ans: C
19. During steady flow compression process of a gas with mass flow rate of 2 kg/s, increase in specific enthalpy is 15kJ/kg and decrease in kinetic energy is 2kJ/kg. The rate of heat rejection to the environment is 3 kW. The power needed to drive the compressor is
(A) 23kW (B) 26kW (C) 29kW (D) 37 kW
Ans: C
20. For steady flow through an insulated horizontal constant diameter pipe, which property remains constant?
(A) Enthalpy (B) Internal energy (C) Entropy (D) Volume
Ans: A
21. For a heat engine operating on the Carnot cycle, the work output is ¼ of the heat transferred to the sink. The efficiency of the engine is (A) 20% (B) 33. 3% (C) 40% (D) 50%
Ans: A
22. A system of 100 kg mass undergoes a process in which its specific entropy increases from 0.3kJ/kg K to 0.4kJ/kg K. At the same time, the entropy of the surrounding decreases from 80kJ/K to 75kJ/K . The process is
(A) Reversible and isothermal (B) Irreversible (C) Reversible only (D) Isothermal only
Ans: B
23. Starting from the same initial conditions, an ideal gas expands from volume V1 to V2 in three different ways, the work done by the gas is W1 if the process is purely isothermal, W2 if purely isobaric and W3 if purely adiabatic, then
(A) W2 > W1 > W3 (B) W2> W3> W1 (C) W1 > W2 > W3 (D) W1 > W3 > W2
Ans: A
24. A house refrigerator with its door open is switched on in a closed room. The air in the room is
(A) Cooled (B) Remains at same temperature (C) Heated (D) Heated or cooled depending on atmospheric pressure
Ans: C
25. A steel ball of mass 1 Kg and specific heat 0.4 KJ/Kg is at a temperature of 60°C. It is dropped into 1 Kg water at 20°C. The final steady state temperature of water is
(A) 23.5°C (B) 30°C (C) 35°C (D) 40°C
Ans: A
26. A gas having a negative Joule-Thomson effect (µ<0), when throttled will
(A) Become cooler
(B) Become warmer
(C) Remain in the same temperature
(D) Become Cooler or warmer depending upon the type of gas
Ans: B
27. The difference between two specific heats Cp-Cv=R/J. This relation is valid for
(A) Any gas (B) Perfect gas (C) Ideal gas (D) Pure gas
Ans: B
28. Three metal walls of the same cross sectional area having thermal conductivities in the ratio 1:2:4 transfer heat at the rate of 6000KJ/hr. For the same wall thickness, the temperature drops will be in the ratio
(A) 1:2:4 (B) 1:1/2:1/4 (C) 1/4 :1/2:1 (D) 1:1:1
Ans: A
29. A grey body is defined such that
(A) Monochromatic emissivity of the body is independent of temperature
(B) Monochromatic emissivity of the body is dependent on temperature
(C) Monochromatic emissivity of the body is independent of wave length
(D) Monochromatic emissivity of the body is dependent on wave length
Ans: C
30. A flat plate of length 1 m and width 50 cm is placed in an air stream at 30°C is blowing parallel to it. The convective heat transfer coefficient is 30 W/(m2K). The heat transfer if the plate is maintained at a temperature of 400°C is__________
(A) 5.55 kW (B) 4.05 kW (C) 55.5 kW (D) 6 Kw
Ans: A
31. It is required to insulate a kitchen oven with cork board (K=0.043 W/(mK) so that the heat losses from the oven does not exceed 400 W/m2 when the inner surface of the oven is at 225°C and the outer surface of the oven is at 40 °C. The thickness of insulation required is nearly
(A) 1cm (B) 2cm (C) 3cm (D) 4cm
Ans: B
32. A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same heat loss and temperature drop, this can be replaced by a layer of diatomite earth of conductivity 0.14W/mK and thickness
(A) 0.05m (B) 0.1m (C) 0.2m (D) 0.5m
Ans: B
33. The maximum net specific work obtained in an ideal Brayton cycle for max temperature 900 K and minimum temperature 400 K is given by
(A) 100Cp (B) 500Cp (C) 800Cp (D) 700Cp
Ans: A
34. An open cycle pressure gas turbine uses a fuel of calorific value 40000kJ/kg with air fuel ratio of 80:1 and develops a net output of 80kJ/kg of air. The thermal efficiency of cycle is
(A) 12% (B) 16% (C) 20% (D) 18%
Ans: B
35. The surface imperfection which separates crystal of different orientation in a poly crystalline aggregate is called
(A) Edge dislocation (B) Stacking fault (C) Grain boundary (D) Screw dislocation
Ans: C
36. The latent heat load in an auditorium is 25% of sensible heat load. The value of sensible heat factor is
(A) 0.3 (B) 0.5 (C) 0.8 (D) 1.0
Ans: C
37. In psychometric charts, what does a vertical downward line represent?
(A) Sensible cooling process (B) Adiabatic saturation process (C) Humidification process (D) Dehumidification process
Ans: D
38. In milk chilling plants, the usual secondary refrigerant is
(A) Ammonia solution (B) Sodium silicate (C) Glycol (D) Brine
Ans: D
39. Which of the non-dimensional number relates the thermal boundary layer and hydrodynamic boundary layer?
(A) Rayleigh number (B) Peclet number (C) Grashoff number (D) Prandtl number
Ans: D
40. In two stage gas turbine plants, with intercooling and reheating
(A) Both work ratio and thermal efficiency increase (B) Work ratio increases but thermal efficiency decreases
(C) Thermal efficiency increases but work ratio decreases (D) Both work ratio and thermal efficiency decrease
Ans: B
41. A plane wall is 25 cm thick with an area of 1 m2, and has a thermal conductivity of 0.5 W/mK. If a temperature difference of 60°C is imposed across it, what is the heat flow?
(A) 120W (B) 140W (C) 160W (D) 180W
Ans: A
42. A solid sphere and a hollow sphere of the same material and size are heated to the same temperature and allowed to cool in the same surroundings. If the temperature difference between the body and that of the surroundings is T, then
(A) Both spheres will cool at the same rate for small values of T
(B) Both spheres will cool at the same rate for high values of T
(C) The hollow sphere will cool at a faster rate for all the values of T
(D) The solid sphere will cool at a faster rate for all the values of T
Ans: C
43. A steel steam pipe 10 cm inner diameter and 11 cm outer diameter is covered with insulation having the thermal conductivity of 1 W/mK. If the convective heat transfer coefficient between the surface of insulation and the surrounding air is 8 W / m2 K, then critical radius of insulation is
(A) 10 cm (B) 11 cm (C) 12.5 cm (D) 15 cm
Ans: C
44. Which one of the following is correct? The effectiveness of a fin will be maximum in an environment with
(A) Free convection (B) Forced convection (C) Radiation (D) Convection and radiation
Ans: A
45. The flash chamber in a single stage simple vapour compression system
(A) increases the refrigerating effect (B) decreases the refrigerating effect
(C) increases the work of compression (D) has no effect on refrigerating effects
Ans: D
46. Which one of the following statements is correct? The non-dimensional parameter known as Stanton number (St) is used in
(A) Forced convection heat transfer over flat plate
(B) Condensation heat transfer with laminar film layer
(C) Natural convection heat transfer over flat plate
(D) Unsteady heat transfer from bodies in which internal temperature gradients cannot be neglected
Ans: A
47. Which substance has minimum value of thermal conductivity
(A) Air (B) Water (C) Plastic (D) Rubber
Ans: A
48. What is hunting of thermostatic expansion valve?
(A) A variation of evaporative load with degree of superheat (B) A variation of pressure of the evaporator with variation of load
(C) Alternate overfeeding and starving of refrigerant flow in the evaporator (D) This is used in connecting with expansion valve
Ans: C
49. In VCRS plant, the refrigerant leaves the compressor and evaporator with enthalpy of 205kJ/ kg and 177kJ/kg respectively. Enthalpy of leaving the condenser is 105kJ/kg . If the mass flow rate of the refrigerant is 0.2kg/sec, then the refrigerant effect will be
(A) 12.2kW (B) 14.4kW (C) 16.4kW (D) 20.2Kw
Ans: B
50. Ozone depletion by CFC occurs by breakdown of
(A) Chlorine atoms from refrigerant by UV radiation and reaction with Ozone in troposphere
(B) Fluorine atoms from refrigerant by UV radiation and reaction with Ozone in troposphere
(C) Chlorine atoms from refrigerant by UV radiation and reaction with Ozone in stratosphere
(D) Fluorine atoms from refrigerant by UV radiation and reaction with Ozone in stratosphere
Ans: C
51. Maximum possible COP of a solar absorption refrigeration system with generator temperature of 360K, absorber temperature of 300K, condenser temperature of 300K and evaporator temperature of 270K is
(A) 9 (B) 6 (C) 3 (D) 1.5
Ans: D
52. Two air streams with mass flow rates of 36 kg/min and 14 kg/min with respective enthalpies of 36 kJ/kg and 50kJ/kg are mixed. The enthalpy of mixture is nearly
(A) 64kJ/kg (B) 55kJ/kg (C) 46kJ/kg (D) 40kJ/kg
Ans: D
53. Out of which cannot be removed from structure of a material?
(A) Point defect (B) Line defect (C) Grain boundary (D) Dislocation
Ans: D
54. At eutectic point, two items are completely
(A) Insoluble in solid and liquid state (B) Soluble in liquid state
(C) Soluble in solid state (D) Insoluble in liquid state
Ans: B
55. Pearlite consists of
(A) 6.67%C and 93.3% ferrite (B) 13% Fe and 87% cementite
(C) 12%C and 87% ferrite (D) 13% cementite and 87% ferrite
Ans: D
56. Alloy containing 65-70% of nickel is called as
(A) Monel metal (B) White cast iron (C) Stainless steel (D) Brass
Ans: A
57. Cupola is used to make
(A) pig iron (B) wrought iron (C) steel (D) cast iron
Ans: D
58. Which of the following process needs no quenching
(A) induction hardening (B) flame hardening (C) nitriding (D) carburizing
Ans: C
59. The Jominy test is used to find
(A) Young’s modulus (B) hardenability (C) yield strength (D) thermal conductivity
Ans: B
60. The crystalline structure of aluminum is
(A) body centered cubic (B) face centered cubic (C) closed packed hexagonal (D) body centered tetragonal
Ans: B
61. The process of reheating the martensitic steel to reduce its brittleness without any significant loss in its hardness is
(A) normalizing (B) annealing (C) quenching (D) tempering
Ans: A
62. If a particular Fe-C alloy contains less than 0.83% carbon it is called
(A) High speed steel (B) Hypoeutectoid steel (C) Hypereutectoid steel (D) Cast iron
Ans: B
63. A system of masses rotating in different parallel planes is in dynamic balance if the resultant
(A) force is equal to zero
(B) couple is equal to zero
(C) force and resultant couple are zero
(D) force is numerically equal to the resultant couple but neither of them need necessarily be zero
Ans: C
64. If n = 0.5 and C= 300 for the cutting speed and the tool life relation, when cutting speed is reduced by 30%, the tool life is increased by (A) 95% (B) 104% (C) 78% (D) 50%
Ans: B
65. In a machining test, a cutting speed of 100 m/min indicated the tool life as 16 min and a cutting speed of 200 m/min indicated the tool life as 4 min. The values of n and C are
(A) 0.5 and 200 (B) 0.25 and 200 (C) 0.5 and 400 (D) 0.25 and 400
Ans: C
66. Which one of the following instruments is widely used to check and calibrate geometric features of machine tools during their assembly?
(A) Ultrasonic probe (B) Coordinate Measuring Machine (CMM) (C) Laser interferometer (D) Vernier calipers
Ans: C
67. The flatness of a machine bed can be measured using
(A) Vernier calipers (B) Auto collimator (C) Height gauge (D) Tool maker’s microscope
Ans: B
68. Which one of the following metal forming processes is not a high energy rate forming process?
(A) Electro-mechanical forming (B) Roll-forming (C) Explosive forming (D) Electro-hydraulic forming
Ans: B
69. Magnetic forming is an example of:
(A) Cold forming (B) Hot forming (C) High energy rate forming (D) Roll forming
Ans: C
70. During the execution of a CNC part program block N020 G02 X45.0 Y25.0 R5.0 the type of tool motion will be
(A) Circular Interpolation – clockwise (B) Circular Interpolation - counter clockwise
(C) Linear Interpolation (D) Rapid feed
Ans: A
71. Arrange the processes in the increasing order of their maximum material removal rate Electrochemical Machining (ECM) Ultrasonic Machining (USM) Electron Beam Machining (EBM) Laser Beam Machining (LBM) and Electric Discharge Machining (EDM)
(A) USM, LBM, EBM, EDM, ECM
(B) EBM, LBM, USM, ECM, EDM
(C) LBM, EBM, USM, ECM, EDM
(D) LBM, EBM, USM, EDM, ECM
Ans: D
72. Which of the following processes has very high material removal rate efficiency?
(A) Electron beam machining (B) Electrochemical machining (C) Electro discharge machining (D) Plasma arc machining
Ans: D
73. In Electro-Discharge Machining (EDM), the tool is made of
(A) Copper (B) High Speed Steel (C) Cast Iron (D) Plain Carbon Steel
Ans: A
74. When 3-2-1 principle is used to support and locate a three dimensional work-piece during machining, the number of degrees of freedom that are restricted is
(A) 7 (B) 9 (C) 10 (D) 8
Ans: B
75. The Poisson’s ratio for perfectly elastic incompressible material is
(A) 0.5 (B) 1 (C) -0.5 (D) 2
Ans: A
76. Assertion (A): A dynamically balanced system of multiple rotors on a shaft can rotate smoothly at the critical speeds of the system. Reason (R): Dynamic balancing eliminates all the unbalanced forces and couples from the system
(A) Both A and R are individually true and R is the correct explanation of A
(B) Both A and R are individually true but R is not the correct explanation of A
(C) A is true but R is false (D) R is true but A is false
Ans: A
77. A rod of length L and diameter D is subjected to a tensile load P. Which of the following is sufficient to calculate the resulting change in diameter?
(A) Young's modulus (B) Shear modulus
(C) Poisson's ratio (D) Both Young's modulus and Shear modulus
Ans: D
78. If the value of Poisson's ratio is zero, then it means that
(A) The material is rigid. (B) The material is perfectly plastic.
(C) There is no longitudinal strain in the material. (D) The longitudinal strain in the material is infinite.
Ans: A
79. Consider the following statements:
1. Two-dimensional stresses applied to a thin plate in its own plane represent the plane stress condition.
2. Under plane stress condition, the strain in the direction perpendicular to the plane is zero.
3. Normal and shear stresses may occur simultaneously on a plane.
Which of the above statements is /are correct?
(A) 1 only (B) 1 and 2 (C) 2 and 3 (D) 1 and 3
Ans: D
80. Starting friction is low in
(A) hydrostatic lubrication (B) hydrodynamic lubrication
(C) mixed (or semi fluid) lubrication (D) boundary lubrication
Ans: A
81. Spherical roller bearing are normally used
(A) for increased radial load (B) for increased thrust load
(C) when there is less radial load (D) to compensate for angular misalignment
Ans: D
82. Which one of the following is a criterion in the design of hydrodynamic journal bearings?
(A) Somerfield number (B) rating life (C) Specific dynamic capacity (D) Rotation factor
Ans: A
83. The crystal structure of austenite is
(A) Body centred cubic (B) Face centred cubic (C) Hexagonal close packed (D) Body centred tetragonal
Ans: B
84. Critical damping is the
(A) largest amount of damping for which no oscillation occurs in free vibration
(B) smallest amount of damping for which no oscillation occur in free vibration
(C) largest amount of damping for which the motion is simple harmonic in free vibration
(D) smallest amount of damping for which the motion is simple harmonic in free vibration
Ans: B
85. Increasing the number of reheating stages in a gas turbine to infinity, makes the expansion tending
(A) Reversible adiabatic (B) Isothermal (C) Isobaric (D) Isochoric
Ans: B
86. For a ductile material toughness is a measure of
(A) Resistance to scratching (B) Ability to absorb energy up to fracture
(C) Ability to absorb energy up to elastic limit (D) Resistance to indentation
Ans: B
87. The main purpose of spheroidising treatment is to improve
(A) Hardness of low carbon steel (B) Machinability of low carbon steel
(C) Machinability of high carbon steel (D) Hardness of high carbon steel
Ans: C
88. A steel hub of 100 mm internal diameter and uniform thickness of 10 mm was heated to a temperature of 300oC to shrink-fit it on a shaft. On cooling, a crack developed parallel to the direction of the length of the hub. Consider the following factors in this regard:
1. Tensile hoop stress
2. Tensile radial stress
3. Compressive hoop stress
4. Compressive radial stress
The cause of failure is attributable to
(A) 1 alone (B) 1 and 3
(C) 1, 2 and 4 (D) 2, 3 and 4
Ans: A
89. If the shear force acting at every section of a beam is of the same magnitude and of the same direction then it represents a
(A) Simply supported beam with a concentrated load at the centre.
(B) Overhung beam having equal overhang at both supports and carrying equal concentrated loads acting in the same direction at the free ends.
(C) Cantilever subjected to concentrated load at the free end.
(D) Simply supported beam having concentrated loads of equal magnitude and in the same direction acting at equal distances from the supports.
Ans: C
90. A uniformly distributed load (UDL)(in kN/m) is acting over the entire length of a 3 m long cantilever beam. If the shear force at the midpoint of cantilever is 6 kN, what is the value of UDL(in kN/m)?
(A) 2 (B) 3 (C) 4 (D) 5
Ans: C
91. A cantilever beam having 5 m length is so loaded that it develops a shearing force of 20T and a bending moment of 20 T-m at a section 2m from the free end. Maximum shearing force and maximum bending moment developed in the beam under this load are respectively 50 T and 125 T-m. The load on the beam is:
(A) 25 T concentrated load at free end
(B) 20T concentrated load at free end
(C) 5T concentrated load at free end and 2 T/m load over entire length
(D) 10 T/m uniformly distributed load over entire length
Ans: D
92. Match List I with List II and select the correct answer using the codes given below the lists:
List I (Property) List II (Testing Machine)
A. Tensile strength 1. Rotating Bending Machine
B. Impact strength 2. Three-Point Loading Machine
C. Bending strength 3. Universal Testing Machine
D. Fatigue strength 4. Izod Testing Machine
Codes: A B C D
(A) 4 3 2 1 (B) 3 2 1 4
(C) 2 1 4 3 (D) 3 4 2 1
Ans: D
93. Assertion (A): Poisson's ratio of a material is a measure of its ductility.
Reason (R): For every linear strain in the direction of force, Poisson's ratio of the material gives the lateral strain in directions perpendicular to the direction of force.
(A) Both A and R are individually true and R is the correct explanation of A
(B) Both A and R are individually true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true
Ans: D
94. Simplex method of solving linear programming problem uses
(A) All the points in the feasible region (B) Only the corner points of the feasible region
(C) Intermediate points within the infeasible region (D) Only the interior points in the feasible region
Ans: B
95. Which one of the following conditions should be satisfied for the application of optimality test on an initial solution of transportation model?
(A) Number of allocations should be less than m + n – 1 (B) Number of allocations should be equal to m + n – 1
(C) Number of allocations should be equal to m + n (D) Number of allocations should be more than m + n
Ans: B
96. At a self-service store, a cashier can serve 10 customers in 5 minutes. On an average 15 customers arrive every 10 minutes. If the arrivals are as per Poisson distribution and services as per exponential distribution, the probability that the cashier would be idle is:
(A) 0.5 (B) 0.75 (C) 0.25 (D) 0
Ans: C
97. In an ideal impulse turbine, the
(A) Absolute velocity at the inlet of moving blade is equal to that at the outlet
(B) Relative velocity at the inlet of the moving blade is equal to that at the outlet
(C) Axial velocity at the inlet is equal to that at the outlet
(D) Whirl velocity at the inlet is equal to that at the outlet
Ans: B
98. In an axial flow impulse turbine, energy transfer takes place due to
(A) Change in relative kinetic energy (B) Change in absolute kinetic energy
(C) Change in pressure energy (D) Change in energy because of centrifugal force
Ans: B
99. Consider the following statements: In an impulse turbine, 1. The relative velocity of steam at inlet and outlet of moving blades are equal. 2. The moving blades are symmetrical. 3. The outlet area of the moving blades is smaller than the inlet area.
(A) 1, 2 and 3 are correct (B) 2 and 3 are correct
(C) 1 and 2 are correct (D) 1 and 3 are correct
Ans: C
100. Which one of the following materials is highly elastic?
(A) Rubber (B) Brass (C) Steel (D) Glass
Ans: C
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