## Interview MCQ Set 1

1. Among the following, production through which material is not possible in a crucible?

a) Glass

b) Metal

c) Pigment

d) Oils

### View Answer

2. Which of the following metals or alloys cannot be used for making crucibles?

a) Nickel

b) Zirconium

c) Mercury

d) Platinum

### View Answer

3. The crucible process is used for production of which material?

a) Pig iron

b) Cast iron

c) Tool steel

d) Gray iron

### View Answer

4. Which of the following is not a property of a crucible?

a) Retention of thermal conductivity

b) Resistance to chemical attack

c) Retention of electrical conductivity

d) Resistance to erosion

### View Answer

5. What is the maximum pressure which the isostatic presses can take for making crucibles?

a) 890 atm

b) 1270 atm

c) 1000 atm

d) 1100 atm

### View Answer

6. Which of the following does not hold valid for an isostatic press?

a) Consistent mixture

b) High pressure operation

c) High density of product

d) Wet mix used

### View Answer

7. Which of the following cannot be counted among the advantages of a crucible?

a) Uniform heating

b) Low flexibility

c) Low installation cost

d) No contamination of charge

### View Answer

8. Production of crucibles is inexpensive.

a) True

b) False

### View Answer

9. Which of the following is not a raw material for making a crucible?

a) Clay

b) Wax

c) Graphite

d) Silicon carbide

### View Answer

10. Crucibles do not possess refractoriness.

a) True

b) False

### View Answer

## Interview MCQ Set 2

1. In cycloidal gears contact area is

a) Comparatively smaller

b) Comparatively larger

c) Can’t be determined

d) None of the listed

### View Answer

2. Involute gears have greater contact area as compared to cycloidal gears.

a) True

b) False

### View Answer

3. Cycloidal teeth consist of

a) Hypocycloid curve

b) Epicycloid gear

c) Both hypocycloid curve and epicycloid curve

d) None of the mentioned

### View Answer

4. Pressure angle remains constant in case of involute profile.

a) True

b) False

### View Answer

5. Pressure angle is _____ in case of cycloidal teeth.

a) Constant

b) Variable

c) zero

d) None of the listed

### View Answer

6. Velocity ratio is the ratio angular velocity of driving gear to that of driven gear.

a) True

b) False

### View Answer

7. Velocity ratio and transmission ratio are the same thing.

a) True

b) False

### View Answer

8. Contact ratio is always

a) =1

b) >1

c) <1

d) Can’t be determined

### View Answer

9. Product of diametric pitch and circular pitch is?

a) π

b) 1/π

c) None of the listed

d) 2

### View Answer

10. Diameteral pitch is 5, then calculate module of the gear.

a) 0.2

b) 0.4

c) 5

d) 10

### View Answer

## Interview MCQ Set 3

1. Superheated R-134a at 0.5 MPa, 20°C is cooled in a piston-cylinder at constant temperature to a final two-phase state with quality of 50%. The refrigerant mass is 5 kg, and during the process 500 kJ of heat is removed. Find the necessary work.

a) -67.9 kJ

b) -77.9 kJ

c) -87.9 kJ

d) -97.9 kJ

### View Answer

^{3}/kg ; u1 = 390.52 kJ/kg => V1 = mv1 = 0.211 m

^{3}State 2: T2 , x2 ⇒ u2 = 227.03 + 0.5 × 162.16 = 308.11 kJ/kg, v2 = 0.000817 + 0.5 × 0.03524 = 0.018437 m

^{3}/kg => V2 = m(v2) = 0.0922 m

^{3}work = -500 – m(u2 – u1) = -500 – 5 × (308.11 – 390.52) = -87.9 kJ.

2. Air at 600 K flows with 3 kg/s into a heat exchanger and out at 100°C. How much (kg/s) water coming in at 100 kPa, 20°C can the air heat to the boiling point?

a) 0.37 kg/s

b) 0.17 kg/s

c) 0.27 kg/s

d) 0.57 kg/s

### View Answer

3. Nitrogen gas flows into a convergent nozzle at 200 kPa, 400 K and very low velocity. It flows out of the nozzle at 100 kPa, 330 K. If the nozzle is insulated find the exit velocity.

a) 681.94 m/s

b) 581.94 m/s

c) 481.94 m/s

d) none of the mentioned

### View Answer

^{2}] / 2 [(V2)

^{2}] = 2(h1 – h2) = 2Cp(T1 – T2) = 2 × 1.042 (400 – 330) = 145.88 kJ/kg = 145 880 J/kg V2 = 381.94 m/s.

4. A steam turbine has an inlet of 2 kg/s water at 1000 kPa, 350°C and velocity of 15 m/s. The exit is at 100 kPa, x = 1 and very low velocity. Find the specific work.

a) 382.3 kJ/kg

b) 482.3 kJ/kg

c) 582.3 kJ/kg

d) 682.3 kJ/kg

### View Answer

^{2}– (V2)

^{2}]/2 + g(z1 – z2) here z1=z2 and V2=0 hence w = (h1 – h2) + [(V1)

^{2}]/2 h1 = 3157.65 kJ/kg, h2 = 2675.46 kJ/kg wT = 3157.65 – 2675.46 + ½ (152/1000) = 482.3 kJ/kg.

5. A steam turbine has an inlet of 2 kg/s water at 1000 kPa, 350°C and velocity of 15 m/s. The exit is at 100 kPa, x = 1 and very low velocity. Find the power produced.

a) 664.6 kW

b) 764.6 kW

c) 864.6 kW

d) 964.6 kW

### View Answer

^{2}– (V2)

^{2}]/2 + g(z1 – z2) here z1=z2 and V2=0 hence w = (h1 – h2) + [(V1)

^{2}]/2 h1 = 3157.65 kJ/kg, h2 = 2675.46 kJ/kg wT = 3157.65 – 2675.46 + ½ (152/1000) = 482.3 kJ/kg thus power produced = (2 kg/s)(482.3 kJ/kg) = 964.6 kW.

6. 10kg of water in a piston-cylinder exists as saturated liquid/vapour at 100 kPa, with a quality of 50%. It is now heated till the volume triples. The mass of piston is such that a cylinder pressure of 200 kPa will float it. Find the heat transfer in the process.

a) 23961 kJ

b) 24961 kJ

c) 25961 kJ

d) 26961 kJ

### View Answer

^{3}/kg State 2: v2, P2 ≤ Plift => v2 = 3 × 0.8475 = 2.5425 m3/kg ; Interpolate: T2 = 829°C, u2 = 3718.76 kJ/kg => V2 = mv2 = 25.425 m

^{3}1W2 = P(lift)(V2 −V1) = 200 × 10 (2.5425 − 0.8475) = 3390 kJ 1Q2 = m(u2 − u1) + 1W2 = 10×(3718.76 − 1461.7) + 3390 = 25961 kJ.

7. A 1L capsule of water at 150°C, 700 kPa is placed in a larger insulated (otherwise evacuated) vessel. The capsule breaks resulting which its contents fill the entire volume. If the final pressure is not to exceed 125 kPa, find the vessel volume?

a) 115 L

b) 125 L

c) 135 L

d) 145 L

### View Answer

^{3}/kg; u1 = uf = 631.66 kJ/kg State 2: P2 , u2 ⇒ x2 =(631.66 – 444.16)/2069.3 = 0.09061 v2 = 0.001048 + 0.09061 × 1.37385 = 0.1255 m

^{3}/kg V2 = m(v2) = 0.916 × 0.1255 = 0.115 m

^{3}= 115 L.

8. A vertical cylinder fitted with a piston contains 5 kg of R-22 at 10°C. Heat is transferred causing the piston to rise until the volume has doubled. Additional heat is transferred until the temperature inside reaches 50°C, at which point the pressure inside the cylinder is 1.3 MPa. Find the work done.

a) 34.1 kJ

b) 44.1 kJ

c) 54.1 kJ

d) 64.1 kJ

### View Answer

^{3}/kg, u3 = 248.4 kJ/kg v1 = 0.010075 = 0.0008 + x1 × 0.03391 => x1 = 0.2735 u1 = 55.92 + 0.2735 × 173.87 = 103.5 kJ/kg State 2: v2 = 0.02015 m

^{3}/kg, P2 = P1 = 681 kPa this is still 2-phase Work = P1(V2 – V1) = 681 × 5 (0.02 – 0.01) = 34.1 kJ.

9. A 250L rigid tank contains methane at 1500 kPa, 500 K. It is now cooled down to 300K. Find the heat transfer.

a) –402.4 kJ

b) –502.4 kJ

c) –602.4 kJ

d) –702.4 kJ

### View Answer

10. A rigid container has 2kg of carbon dioxide gas at 1200 K, 100 kPa that is heated to 1400 K. Find the heat transfer using heat capacity.

a) 231.2 kJ

b) 241.2 kJ

c) 251.2 kJ

d) 261.2 kJ

### View Answer

11. A piston cylinder contains 3kg of air at 20°C and 300 kPa. It is now heated up in a constant pressure process to 600 K. Find the heat transfer.

a) 941 kJ

b) 951 kJ

c) 961 kJ

d) 971 kJ

### View Answer

^{3}Process: P = constant, work = ⌠ PdV = P (V2 – V1) = 300 (1.722 – 0.8413) = 264.2 kJ Energy equation: U2 – U1 = 1Q2 – 1W2 = m(u2 – u1) Q2 = U2 – U1 + 1W2 = 3(435.097 – 209.45) + 264.2 = 941 kJ.

## Interview MCQ Set 4

1. What do we get on equating the first and second TdS equations?

a) Cp-Cv = T*(∂T/∂p)*(∂V/∂T)

b) Cp-Cv = T*(∂p/∂T)*(∂V/∂T)

c) Cp+Cv = T*(∂p/∂T)*(∂V/∂T)

d) none of the mentioned

### View Answer

2. Consider the equation Cp-Cv = -T*(∂p/∂V)(∂V/∂T)^{2} , which of the following is correct?

a) (∂V/∂T)^{2} is always positive

b) (∂p/∂V) for any substance is negative

c) (Cp-Cv) is always positive

d) all of the mentioned

### View Answer

3. When do we have the condition Cp=Cv?

a) as T approaches 0K, Cp tends to approach Cv

b) when (∂V/∂T)=0, Cp=Cv

c) both of the mentioned are correct

d) none of the mentioned are correct

### View Answer

^{2}.

4. For an ideal gas,

a) Cp-Cv = R

b) Cp-Cv = mR

c) Cp=Cv

d) all of the mentioned

### View Answer

5. The volume expansivity and isothermal compressibility is defined as

a) volume expansivity = (1/V)*(∂V/∂T) at p and isothermal compressibility = (-1/V)*(∂V/∂T) at T

b) volume expansivity = (1/V)*(∂V/∂T) at p and isothermal compressibility = (-1/V)*(∂V/∂T) at T

c) volume expansivity = (1/V)*(∂V/∂T) at p and isothermal compressibility = (-1/V)*(∂V/∂T) at T

d) none of the mentioned

### View Answer

6. The equation Cp-Cv = -T*(∂p/∂V)(∂V/∂T)^{2} can also be expressed as

a) Cp-Cv = T*V*(isothermal compressibility)^{2} / (volume expansivity)

b) Cp-Cv = T*V*(isothermal compressibility) / (volume expansivity)

c) Cp-Cv = T*V*(volume expansivity)^{2} / (isothermal compressibility)

d) Cp-Cv = T*V*(volume expansivity) / (isothermal compressibility)

### View Answer

^{2}when we use volume expansivity and isothermal compressibility in it.

7. At constant entropy, the two TdS equations give us the relation

a) Cp+Cv = 0

b) Cp=Cv

c) Cp-Cv = mR

d) Cp/Cv = ɣ

### View Answer

8. The slope of an isentrope is ____ the slope of an isotherm on p-v diagram.

a) less than

b) greater than

c) equal to

d) less than or equal to

### View Answer

9. Work done in reversible and isothermal compression is ____ the work done in reversible and adiabatic compression.

a) equal to

b) greater than

c) less than

d) less than or equal to

### View Answer

10. Isothermal compression requires minimum work.

a) true

b) false

### View Answer

11. Which of the following relation gives ɣ .

a) 1/(isothermal compressibility *adiabatic compressibility)

b) isothermal compressibility * adiabatic compressibility

c) adiabatic compressibility / isothermal compressibility

d) isothermal compressibility / adiabatic compressibility

### View Answer

## Interview MCQ Set 5

1. Among spur gear and helical gear, which has smooth engagement and thus lesser noise?

a) Helical Gears

b) Spur Gears

c) Both have equal noises

d) Can’t be determined

### View Answer

2. There is same type of tooth meshing in helical and spur gear.

a) True

b) False

### View Answer

3. Among the normal module and transverse module, which one has greater value?

a) Normal Module

b) Transverse Module

c) Both have equal module

d) Insufficient information

### View Answer

4. Below is a representation of a helical gear. Blue lines in the figure signify?

a) Pinion right handed helical teeth

b) Pinion left handed helical teeth

c) Both right and left handed

d) Symmetric helical teeth

### View Answer

5. Below is a representation of a helical gear. Blue lines in the figure signify?

a) Pinion right handed helical teeth

b) Pinion left handed helical teeth

c) Both right and left handed

d) Symmetric helical teeth

### View Answer

6. A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22⁰ and normal pressure angle 19⁰. The normal module is taken as 4mm. Calculate the transverse module.

a) 4.3mm

b) 4.1mm

c) 3.9mm

d) 3.7mm

### View Answer

7. A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22⁰ and normal pressure angle 19⁰. The normal module is taken as 4mm. Calculate the transverse pressure angle in degrees.

a) 17.9

b) 20.4

c) 19.6

d) 18.4

### View Answer

8. A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22⁰ and normal pressure angle 19⁰. The normal module is taken as 4mm. Calculate the axial pitch.

a) None of the listed

b) 34.2mm

c) 33.4mm

d) 29.6mm

### View Answer

9. A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22⁰ and normal pressure angle 19⁰. The normal module is taken as 4mm. Calculate the pitch circle diameter of pinion.

a) 64.7mm

b) 52.6mm

c) 56.6mm

d) 68.8mm

### View Answer

10. A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22⁰ and normal pressure angle 19⁰. The normal module is taken as 4mm. Calculate the pitch circle diameter of the gear.

a) 172.6mm

b) 142.6mm

c) 180.3mm

d) 202.4mm

### View Answer

11. A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22⁰ and normal pressure angle 19⁰. The normal module is taken as 4mm. Calculate the centre distance.

a) 125.4mm

b) 132.6mm

c) 118.65mm

d) 145.4mm

### View Answer

12. A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22⁰ and normal pressure angle 19⁰. The normal module is taken as 4mm. Calculate addendum circle diameter of the pinion.

a) 59.2mm

b) 72.7mm

c) 65.4mm

d) None of the listed

### View Answer

13. A pair of parallel helical gears consist of 15 teeth pinion meshing with a 40 teeth gear. The helix angle is 22⁰ and normal pressure angle 19⁰. The normal module is taken as 4mm. Calculate the dedendum circle diameter of the pinion.

a) 64.5mm

b) 54.7mm

c) 59.2mm

d) None of the listed

### View Answer

14. The direction of tangential component for a driving gear is same to the direction of rotation.

a) True

b) False

### View Answer

15. If tangential component of force on tooth is 200N and helix angle is 25⁰, calculate the axial component of the force.

a) 200N

b) 302.5N

c) 93.26N

d) 215.6N