chemical engineering MCQs – Page 212

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs

4221. What is the thermal conductivity of a perfect heat insulator ?
0

A. Between 0 and ?

B. One

C. ?

D. Zero

4222. Heat transfer co-efficient (h1) for liquids increases with__________________?
0

A. Decreasing temperature

B. None of these

C. Increasing temperature

D. Decreasing Reynolds number

4223. For the same heat transfer area and the terminal conditions, the ratio of the capacities of a single effect evaporator to a triple effect evaporator is_________________?
0

A. 3

B. 1

C. 1.33

D. 0.33

4224. In a single effect evaporator, the economy is________________?
0

A. < 1

B. > 1

C. 1

D. None of these

4225. In a shell and tube heat exchanger, the tube side heat transfer co-efficient just at the entrance of the tube is_________________?
0

A. Infinity

B. None of these

C. Zero

D. Same as average heat transfer co-efficient for tube side

4226. A 10 cm dia steam pipe, carrying steam at 180C, is covered with an insulation (conductivity = 0.6 W/m.C). It losses heat to the surroundings at 30C. Assume a heat transfer co-efficient of 0.8 W/m2.C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be__________________?
0

A. Less than the steam pipe with 5 cms insulation

B. Equal to that of the un-insulated steam pipe

C. Greater than that for un-insulated steam pipe

D. Less than that of the un-insulated steam pipe

4227. Steam is routed through the tube in case of a ______________ evaporator?
0

A. Horizontal tube

B. Basket type

C. Short tube vertical

D. Long tube vertical

4228. The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is______________?
0

A. Dependent on NRe only

B. 1.66

C. 3.66

D. 88.66

4229. Economy of a multiple effect evaporator depends upon the _____________________?
0

A. Heat balance consideration

B. Rate of heat transfer

C. Both A. and B.

D. Neither A. nor B.

4230. Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80C and leaves at 50C. Cold oil (0.05 m3/min) of density 800 kg/m3 and specific heat of 2 kJ/kg.K enters at 20C. The log mean temperature difference in C is approximately ?
0

A. 50

B. 32

C. 45

D. 37

4231. Trap is used to remove ________________ from steam pipe lines?
0

A. Steam

B. Non-condensable

C. None of these

D. Condensate

4232. Boiling of milk in an open vessel is an example of ______________ boiling?
0

A. Sub-cooled

B. None of these

C. Film

D. Saturated nucleate

4233. In a multipass shell and tube heat exchanger, tube side return pressure loss is equal to _____________ the velocity head?
0

A. Twice

B. Square root of

C. Four times

D. Square of

4234. In the equation Q = UA?t; ?t is_________________________?
0

A. Arithmetic mean temperature difference

B. Geometric mean temperature difference

C. The difference of average bulk temperatures of hot and cold fluids

D. Logarithmic mean temperature difference

4235. In Joules experiment, an insulated container contains 20 kg of water initially at 25C. It is stirred by an agitator, which is made to turn by a slowly falling body weighing 40 kg through a height of 4 m. The process is repeated 500 times. The acceleration due to gravity is 9.8 ms-2. Neglecting the heat capacity of agitator, the temperature of water (in C) is________________?
0

A. 25

B. 34.4

C. 40.5

D. 26.8

4236. As per Kirchoff?s law, the ratio of the total radiating power to the absorptivity of a body depends on the_______________?
0

A. Temperature of the body only

B. Wavelength of monochromatic radiation

C. Both A. and B.

D. Nature of material of body

4237. Heat flux through several resistances in series in analogous to the current flowing through several_____________________?
0

A. Capacitors in series

B. Resistances in series

C. Resistances in parallel

D. None of these

4238. Sensible heat of hot industrial flue gases cannot be recovered by a/an________________?
0

A. Economiser

B. None of these

C. Ceramic recuperator

D. Regenerator

4239. Which area is used in case of heat flow by conduction through a cylinder ?
0

A. Logarithmic mean area

B. None of these

C. Arithmetic mean area

D. Geometric mean area

4240. If all the conditions and dimensions are same, then the ratio of velocity through the tubes of a double pass heat exchanger to that through the single pass heat exchanger is_________________?
0

A. 4

B. 2-Jan

C. 1

D. 2

Previous Next

Showing 4221 to 4240 of 8709 mcqs