CS/B.Tech(AUE-OLD)/SEM-4/AUE-402/2012
2012
HEAT TRANSFER AND COMBUSTION
Time Allotted : 3 Hours Full Marks : 70
The figures in the margin indicate full marks.
Candidates are required to give their answers in their own words
as far as practicable.
GROUP – A
( Multiple Choice Type Questions )
1. Choose the correct alternatives for the following :
10x1 = 10
i) The concept of log mean area is normally used in the
analysis of
a) composite plane surface
b) cylindrical surface
c) spherical surface
d) any plane surface.
ii) The value of 'k' in ( w/m°C ) for glass is near about
a) 20 – 35 b) 0·2 – 0·4
c) 0·7 – 0·75 d) 0·03 – 0·05.
iii) The wavelength of thermal radiation in m is
a) 10 2 – 105 b) 0·01 – 102
c) 10 – 2 – 10– 5 d) 105 – 1010 .
iv) The rate of radial heat transfer through a hollow
cylinder increases as the ratio of outer radius to inner
radius
a) decreases b) increases
c) remains same d) unpredictable.
v) The unit of the thermal diffusivity is
a) m2/hr°C b) kcal/hr°C
c) m2/s d) m/s2 .
vi) A non-dimensional number not associated with natural
convection is
a) Reynolds number b) Nusselt number
c) Grashoff number d) Prandtl number.