chemical engineering heat transfer chemical engineering MCQs – Page 12

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 Review each marked answer and report any item that may be outdated or unclear.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

221. In case of heat flow by conduction for a cylindrical body with an internal heat source, the nature of temperature distribution is_________________?
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A. Linear

B. Parabolic

C. Hyperbolic

D. None of these

222. In the free convection regime of pool boiling, the heat flux is proportional to__________________?
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A. ?t1/2

B. ?t2

C. ?t

D. ?t5/4

223. 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________________?
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A. 25

B. 40.5

C. 34.4

D. 26.8

224. A tank painted with which of the following coloured paints, would heat up maximum by radiation from sun ?
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A. Yellow paint

B. Grey paint

C. White paint

D. Black paint

225. The thickness of condensate layer in filmwise condensation depends on the__________________?
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A. All A., B. and C.

B. Condensation rate

C. Liquid flow rate from the surface

D. Surface configuration

226. Viscous & heat sensitive liquids are concentrated in _____________ evaporators?
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A. Open pan

B. None of these

C. Long tube

D. Agitated film

227. The equation, (NSt N2/3 Pr) = f/2, is the ____________ analogy ?
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A. Colburn

B. Prandtl

C. None of these

D. Reynolds

228. Plancks distribution law is valid for _____________ bodies?
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A. All A., B. & C.

B. Coloured

C. White

D. Black

229. The radiation heat flux from a heating element at a temperature of 800C, in a furnace maintained at 300C is 8 kW/m2. The flux, when the element temperature is increased to 1000C for the same furnace temperature is_____________________?
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A. 12.0 kW/m2

B. 11.2 kW/m2

C. 14.6 kW/m2

D. 16.5 kW/m2

230. Finned tube heat exchangers__________________?
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A. Give larger area per tube

B. Use metal fins of low thermal conductivity

C. Are used for smaller heat load

D. Facilitate very large temperature drop through tube wall

231. Trap is used to remove ________________ from steam pipe lines?
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A. Non-condensable

B. Steam

C. Condensate

D. None of these

232. With increase in temperature, the thermal conductivity of a gas ___________________?
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A. May increase or decrease depending on the type of gas

B. Decreases

C. Increases

D. Remain same

233. For hot feed, forward feeding as compared to backward feeding results in ______________ economy?
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A. No effect on

B. Increased

C. Decreased

D. None of these

234. A sphere of radius R1 is enclosed in a sphere of radius R2. The view (or shape) factor for radiative heat transfer of the outer sphere with respect to the inner sphere is ________________?
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A. (R1/R2)2

B. R2/(R1+R2)

C. 0

D. 1

235. Fresh orange juice contains 12% (by weight) solids and the rest water 90% of the fresh juice is sent to an evaporator to remove water and subsequently mixed with the remaining 10% of fresh juice. The resultant product contains 40% solids. The kg of water removed from 1 kg fresh juice is__________________?
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A. 0.7

B. 0.5

C. 0.4

D. 0.6

236. The film co-efficient between condensing vapour and metal wall increases with _____________________?
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A. Increasing temperature drop

B. Increasing viscosity of the film of condensate

C. Decreasing temperature of the vapour

D. Increasing temperature of the vapour

237. _____________ heat exchanger is used for chilling oil to be dewaxed?
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A. Fixed tube

B. U-tube

C. Double pipe

D. Floating head

238. With increase in temperature, the thermal conductivity of non-metallic amorphous solids_________________?
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A. Decreases

B. Remain constant

C. First decreases upto certain temperature and then increases

D. Increases

239. Multiple effect evaporators are commonly used in the manufacture of P. Paper Q. Superphosphate R. Sugar S. Fats ?
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A. R and S

B. P and S

C. P and Q

D. P and R

240. Nusselt number is the ratio of the ____________________?
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A. Temperature difference to the temperature gradient at the wall

B. Heat flux at the wall to that across the entire pipe

C. None of these

D. Temperature gradient of the wall to that across the entire pipe

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