chemical engineering heat transfer chemical engineering MCQs – Page 16

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering heat transfer chemical engineering Mcqs

301. A measure of the extent to which viscous heating is important relative to the heat flow resulting from the impressed temperature difference is represented by the _______________ number?
0

A. Condensation

B. Grashoff

C. Stanton

D. Brinkman

302. Prandtl and Reynolds analogies are identical for Prandtl number value of__________________?
0

A. 0

B. 1

C. 5

D. 0.5

303. According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor) ?
0

A. f/4

B. f/2

C. f

D. 2f

304. Evaporation of 1kg of water from a solution in a single effect evaporator requires about ________________ kg of steam?
0

A. 1-1.3

B. 2 2.4

C. 1.8-2

D. 0.4 0.6

305. For an ideal black body______________________?
0

A. Transmissivity = 1

B. Absorptivity = 1

C. Reflectivity = 1

D. Emissivity = 0

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

A. ?

B. Between 0 and ?

C. One

D. Zero

307. The rate of heat transfer is a product of overall heat transfer co-efficient, the difference in temperature and the___________________?
0

A. Heating volume

B. None of these

C. Heat transfer area

D. Nusselt number

308. Kirchoff?s law applies to _____________ radiation?
0

A. Total

B. Monochromatic

C. Both A. & B.

D. Neither A. nor B.

309. Crystal size in a continuous crystalliser depends upon the___________________?
0

A. Rate of heat transfer

B. All A., B. and C

C. Degree of super-saturation

D. Degree of turbulence

310. The energy radiated from a surface Q at absolute temperature T is related as__________________?
0

A. None of these

B. Q ? T3

C. Q ? T4

D. Q ? T2

311. Film boiling is usually not desired in commercial equipments, because____________________?
0

A. None of these

B. It is difficult to maintain

C. The heat transfer rate is low in view of the large temperature drop

D. It is not economic

312. The main function of baffles provided in a shell and tube heat exchanger is to______________?
0

A. All A , B & C

B. Hold the tubes in position

C. Enhance turbulence

D. Facilitate the cleaning of outer tube surface

313. Double pipe heat exchangers are preferably useful, when____________________?
0

A. Overall heat transfer co-efficient is very high

B. Requirement of heat transfer area is low

C. High viscosity liquid is to be cooled

D. A corrosive liquid is to be heated

314. For small temperature difference, the heat transfer rate as per Newtons law of cooling is proportional to (where, ?t = excess temperature) ?
0

A. ?t2

B. ?t3

C. ?t

D. ?(?t)

315. A long iron rod initially at a temperature of 20C has one end dipped in boiling water (100C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?
0

A. t = 283 s

B. t = 400 s

C. t = 356 s

D. t = 800 s

316. Pick out the wrong statement ?
0

A. Longitudinal fins are used in extended surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube

B. In a shell and tube heat exchanger, the shell pressure drop is maximum for orifice baffles

C. Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient

D. S.I. unit of fouling factor is Watt/m2.K

317. For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area___________________?
0

A. Decreases

B. Increases

C. Passes through a maxima

D. Remain constant

318. Latent heat absorbed by 1 lb of water at 212F, when it is changed to steam at 212F, may be around ______________ BTU?
0

A. None of these

B. 180

C. 3.97

D. 970

319. Radiation heat transfer rates does not depend upon the_________________?
0

A. Type of absorbing surface

B. Surface area and temperature of the heat source

C. None of these

D. Distance between the heat source and the object receiving the heat

320. Rate of heat transfer by vaporisation from pools of water is affected by the ____________________?
0

A. Surface tension of water

B. Viscosity of water

C. All A., B. and C.

D. Nature of heating surface and distribution of bubbles

Previous Next

Showing 301 to 320 of 511 mcqs