# Practice Test: Question Set - 49

**1. The pressure drop per unit length for laminar flow of fluid through a long pipe is proportional to (where,**

*A*= cross-sectional area of the pipe &*D*= Diameter of the pipe)- (A)

*A*

- (B)

*D*

- (C) 1/

*A*

- (D) 1/

*A*

^{2}

**2. The minimum temperature to which the water can be cooled in a cooling tower is the __________ temperature of air.**

- (A) Ambient

- (B) Dry bulb

- (C) Dew point

- (D) Wet bulb

**3. In case of compression of one kg of air, the work done will be the least, when the value of polytropic index '**

*n*' is- (A) 1

- (B) 1.4

- (C) 1.5

- (D)

*Y*=

*C*/

_{p}*C*

_{v}**4. If the head is doubled in & centrifugal pump, the power required will increase in the ratio of**

- (A) 2

^{3}

- (B) 2

^{3/2}

- (C) 2

^{5/2}

- (D) 2

^{1/3}

**5. Consider an ideal solution of components A and B. The entropy of mixing per mole of an alloy containing 50% B is**

- (A) R ln 2

- (B) -R ln 2

- (C) 3 R ln 2

- (D) -3R ln 2

**6. Brazing filler metal used for joining steel plates**

- (A) Melts below the melting points of base metals

- (B) Melts below 300°C

- (C) Is copper phosphorous alloy

- (D) Is copper

**7. For grinding of softer materials, the grinding wheel should have __________ grain size.**

- (A) Finer

- (B) Coarser

- (C) Medium

- (D) Any type of

**8. The activity of pure hydrogen gas at 1000°C and 5 atm pressure**

- (A) Is always less than 1

- (B) Is always greater than 1

- (C) Can be 5

- (D) Depends on the choice of the standard state

**9. A furnace is made of a refractory brick wall of thickness 0.5 meter and thermal conductivity 0.7 W/m.°K For the same temperature drop and heat loss, this refractory wall can be replaced by a layer of diatomaceous earth of thermal conductivity 0.14 W/m.K and thickness __________ meter.**

- (A) 0.01

- (B) 0.1

- (C) 0.25

- (D) 0.5

**10. Melting point & boiling points of liquid oxygen are respectively - 218.8°C & - 183°C, while the same for liquid nitrogen is - 210°C & - 195.8°C respectively. The difference in melting points of liquid oxygen & liquid nitrogen is not equal to 8.8**

- (A) °C

- (B) °F

- (C) °K

- (D) °R

**11. Production of one ton of paper in Indian paper industry consumes about __________ kWh of electricity.**

- (A) 300

- (B) 800

- (C) 1400

- (D) 2000

**12. __________ metal is used as a bearing liner material.**

- (A) Pewter

- (B) White

- (C) Babbitt

- (D) Gun

**13. The laminar boundary layer thickness in zero pressure gradient flow over a flat plate along the x-direction varies as x**

^{0.5}while the thickness of turbulent boundary layer varies as (where, x = distance from the leading edge)- (A) x

^{1.5}

- (B) x

^{0.8}

- (C) x

^{-1.5}

- (D) x

^{-0.8}

**14. Regeneration of molecular sieve requires it to be heated to a temperature of about __________ °C.**

- (A) 80-120

- (B) 200-300

- (C) 600-800

- (D) 1000-1100

**15. Exposure to __________ accelerates the degradation of plastics.**

- (A) Ultraviolet radiation

- (B) High atmospheric temperature

- (C) High ambient temperature

- (D) Damp atmosphere

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