ISRO Past Year Paper (Mechanical) - 2020 - ISRO, GATE & IES/ESE Mechanical Previous Year Solved Papers - Mechanical Engineering

 Page 1


ISRO Scientist or Engineer Mechanical 2020
               
              
               
 
  
.
Page 2


ISRO Scientist or Engineer Mechanical 2020
               
              
               
 
  
.
Mechanical
Instructions
For the following questions answer them individually
Question 1
A centrifugal pump havingan impeller diameterof 127 mm,delivers a powerof 12 hp. If the impesrer Giameter is changed to 254 mm,
what is the power, if other parameters are kept constant?
A    48hp
B    192 hp
C    24 hp
D    96 hp
Answer: D
Question 2
In a circular tube of diameter 100 mm and length 13 m with laminarlow,the friction factor is estimated to be 0.05. Calculate the
Reynolds number?
A    950
B    2300
C    1280
D    None of the above
Answer: C
Question 3
An open tankis filled with waterto a height of 20m. Whatis the velocity of the water flow at the outlet, if the outlet is at the base of the
tank?
A    
40  (approx.)
B    
20  (approx.)
C    
10  (approx.)
D    
5  (approx.)
Answer: B
Question 4
For a non-dimensional specific speed value of 1, for maximum efficiency, which of the following turbines is preferred?
A    Pelton wheel
B    Francis turbine
C    Kaplan turbine
D    Tyson wheel
Answer: B
s
m
s
m
s
m
s
m
  
.
Page 3


ISRO Scientist or Engineer Mechanical 2020
               
              
               
 
  
.
Mechanical
Instructions
For the following questions answer them individually
Question 1
A centrifugal pump havingan impeller diameterof 127 mm,delivers a powerof 12 hp. If the impesrer Giameter is changed to 254 mm,
what is the power, if other parameters are kept constant?
A    48hp
B    192 hp
C    24 hp
D    96 hp
Answer: D
Question 2
In a circular tube of diameter 100 mm and length 13 m with laminarlow,the friction factor is estimated to be 0.05. Calculate the
Reynolds number?
A    950
B    2300
C    1280
D    None of the above
Answer: C
Question 3
An open tankis filled with waterto a height of 20m. Whatis the velocity of the water flow at the outlet, if the outlet is at the base of the
tank?
A    
40  (approx.)
B    
20  (approx.)
C    
10  (approx.)
D    
5  (approx.)
Answer: B
Question 4
For a non-dimensional specific speed value of 1, for maximum efficiency, which of the following turbines is preferred?
A    Pelton wheel
B    Francis turbine
C    Kaplan turbine
D    Tyson wheel
Answer: B
s
m
s
m
s
m
s
m
  
.
Question 5
An experiment is conducted with a fluid of density 1  at 10  velocity. The free stream static pressure is 100 kPa and the local
static pressure is 101 kPa. What is thepressure coefficient at the location?
A    70
B    80
C    20
D    50
Answer: C
Question 6
In a P-V diagram of a steady flow compressor, the intercooling can be represented as
A    Vertical line
B    Horizontal line
C    Parabolic line
D    None of the above
Answer: B
Question 7
Whichof the following is a non-Newtonian fluid?
A    Air
B    Water
C    Gasoline
D    None of the above
Answer: D
Question 8
A hot body at 1000 K transfers 2000 kJ of heat to a body at 500 K. Determinethe net entropy change?
A    
+4 
B    
-2 
C    
+2 
D    
-4 
Answer: C
Question 9
Highest ratio of specific heat is possible for?
m
3
k g
s
m
K g
K J
K g
K J
K g
K J
K g
K J
  
.
Page 4


ISRO Scientist or Engineer Mechanical 2020
               
              
               
 
  
.
Mechanical
Instructions
For the following questions answer them individually
Question 1
A centrifugal pump havingan impeller diameterof 127 mm,delivers a powerof 12 hp. If the impesrer Giameter is changed to 254 mm,
what is the power, if other parameters are kept constant?
A    48hp
B    192 hp
C    24 hp
D    96 hp
Answer: D
Question 2
In a circular tube of diameter 100 mm and length 13 m with laminarlow,the friction factor is estimated to be 0.05. Calculate the
Reynolds number?
A    950
B    2300
C    1280
D    None of the above
Answer: C
Question 3
An open tankis filled with waterto a height of 20m. Whatis the velocity of the water flow at the outlet, if the outlet is at the base of the
tank?
A    
40  (approx.)
B    
20  (approx.)
C    
10  (approx.)
D    
5  (approx.)
Answer: B
Question 4
For a non-dimensional specific speed value of 1, for maximum efficiency, which of the following turbines is preferred?
A    Pelton wheel
B    Francis turbine
C    Kaplan turbine
D    Tyson wheel
Answer: B
s
m
s
m
s
m
s
m
  
.
Question 5
An experiment is conducted with a fluid of density 1  at 10  velocity. The free stream static pressure is 100 kPa and the local
static pressure is 101 kPa. What is thepressure coefficient at the location?
A    70
B    80
C    20
D    50
Answer: C
Question 6
In a P-V diagram of a steady flow compressor, the intercooling can be represented as
A    Vertical line
B    Horizontal line
C    Parabolic line
D    None of the above
Answer: B
Question 7
Whichof the following is a non-Newtonian fluid?
A    Air
B    Water
C    Gasoline
D    None of the above
Answer: D
Question 8
A hot body at 1000 K transfers 2000 kJ of heat to a body at 500 K. Determinethe net entropy change?
A    
+4 
B    
-2 
C    
+2 
D    
-4 
Answer: C
Question 9
Highest ratio of specific heat is possible for?
m
3
k g
s
m
K g
K J
K g
K J
K g
K J
K g
K J
  
.
A    Argon
B    Helium
C    Hydrogen
D    Air
Answer: A
Question 10
Which of the following can be used to determine the variation of saturation pressure with temperature along phase boundaries?
A    Joule -Thomson relation
B    Carnot equation
C    Rankine-Hougoniot’s relation
D    Clausius—Clapeyronrelation
Answer: D
Question 11
Air at C and 100 kPa enters in a steady flow to a nozzle at a velocity of 100 . If theinlet area of the nozzle is 0.5 , what is the
mass flow rate through the system
A    
116 
B    
232 
C    
58 
D    
143 
Answer: C
Question 12
Critical point of wateris
A    22.06 kPa
B    22.06 MPa
C    22.06 atm
D    22.06 mbar
Answer: B
Question 13
In a shower mixer, cold water at 27 deg C, flowing at 5 kg/min is mixed with hot water at 77 deg C flowing at 15 kg/min.The exit
temperature of the mixture is
A    45.4 deg C
B    
64.5 deg C
2 7
°
s
m
m
2
s
k g
s
k g
s
k g
s
k g
  
.
Page 5


ISRO Scientist or Engineer Mechanical 2020
               
              
               
 
  
.
Mechanical
Instructions
For the following questions answer them individually
Question 1
A centrifugal pump havingan impeller diameterof 127 mm,delivers a powerof 12 hp. If the impesrer Giameter is changed to 254 mm,
what is the power, if other parameters are kept constant?
A    48hp
B    192 hp
C    24 hp
D    96 hp
Answer: D
Question 2
In a circular tube of diameter 100 mm and length 13 m with laminarlow,the friction factor is estimated to be 0.05. Calculate the
Reynolds number?
A    950
B    2300
C    1280
D    None of the above
Answer: C
Question 3
An open tankis filled with waterto a height of 20m. Whatis the velocity of the water flow at the outlet, if the outlet is at the base of the
tank?
A    
40  (approx.)
B    
20  (approx.)
C    
10  (approx.)
D    
5  (approx.)
Answer: B
Question 4
For a non-dimensional specific speed value of 1, for maximum efficiency, which of the following turbines is preferred?
A    Pelton wheel
B    Francis turbine
C    Kaplan turbine
D    Tyson wheel
Answer: B
s
m
s
m
s
m
s
m
  
.
Question 5
An experiment is conducted with a fluid of density 1  at 10  velocity. The free stream static pressure is 100 kPa and the local
static pressure is 101 kPa. What is thepressure coefficient at the location?
A    70
B    80
C    20
D    50
Answer: C
Question 6
In a P-V diagram of a steady flow compressor, the intercooling can be represented as
A    Vertical line
B    Horizontal line
C    Parabolic line
D    None of the above
Answer: B
Question 7
Whichof the following is a non-Newtonian fluid?
A    Air
B    Water
C    Gasoline
D    None of the above
Answer: D
Question 8
A hot body at 1000 K transfers 2000 kJ of heat to a body at 500 K. Determinethe net entropy change?
A    
+4 
B    
-2 
C    
+2 
D    
-4 
Answer: C
Question 9
Highest ratio of specific heat is possible for?
m
3
k g
s
m
K g
K J
K g
K J
K g
K J
K g
K J
  
.
A    Argon
B    Helium
C    Hydrogen
D    Air
Answer: A
Question 10
Which of the following can be used to determine the variation of saturation pressure with temperature along phase boundaries?
A    Joule -Thomson relation
B    Carnot equation
C    Rankine-Hougoniot’s relation
D    Clausius—Clapeyronrelation
Answer: D
Question 11
Air at C and 100 kPa enters in a steady flow to a nozzle at a velocity of 100 . If theinlet area of the nozzle is 0.5 , what is the
mass flow rate through the system
A    
116 
B    
232 
C    
58 
D    
143 
Answer: C
Question 12
Critical point of wateris
A    22.06 kPa
B    22.06 MPa
C    22.06 atm
D    22.06 mbar
Answer: B
Question 13
In a shower mixer, cold water at 27 deg C, flowing at 5 kg/min is mixed with hot water at 77 deg C flowing at 15 kg/min.The exit
temperature of the mixture is
A    45.4 deg C
B    
64.5 deg C
2 7
°
s
m
m
2
s
k g
s
k g
s
k g
s
k g
  
.
C    
34.5 deg C
D    68.4 deg C
Answer: B
Question 14
Which ofthe following uses a regenerator?
A    Brayton cycle
B    Ericsson cycle
C    Stirling Cycle
D    Both (b) and (c)
Answer: D
Question 15
Ratio of convective mass transfer to the massdiffusionrate is called?
A    Sherwood number
B    Schmidt number
C    Rayleigh number
D    Strouhal number
Answer: A
Question 16
A gas is containedin a cylinder with a moveable piston of 100 kg mass. When 2500 J of heat flows into the gas, the internal energy of
the gas increases by 1500 J. Whatis the distance through which the piston rises?
A    2 m
B    1 m
C    2.5 m
D    0.5 m
Answer: B
Question 17
A refrigerator with COP of 6 is used in a room at 300 K. Whatwill be the heat intake through a section of refrigerator wall of area 
 with a thickness of 10 cm assuming only conduction? Value of thermal conductivity of the wall can be taken as 1 
.K
A    5000 W
B    1000 W
C    7500 W
D    3000 W
Answer: E
1 0 0 c m × 1 0 0 c m
c m
W
  
.