Question: Free convection flow depends on
[A].density
coefficient of viscosity
gravitational force
all of these
[A].
[B].
[C].
[D].
Answer: Option D
Explanation:
No answer description available for this question.
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An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m2). The critical thickness of insulation will be
Question: An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m2). The critical thickness of insulation will be
[A].25 mm
40 mm
160 mm
800 mm
[A].
[B].
[C].
[D].
Answer: Option A
Explanation:
No answer description available for this question.
Fourier’s law of heat conduction gives the heat flow for
Question: Fourier’s law of heat conduction gives the heat flow for
[A].irregular surfaces
non-uniform temperature surfaces
one dimensional cases only
two dimensional cases only
[A].
[B].
[C].
[D].
Answer: Option C
Explanation:
No answer description available for this question.
BRISTLE : BRUSH
Question: BRISTLE : BRUSH
[A].arm : leg
stage : curtain
recline : chair
key : piano
[A].
[B].
[C].
[D].
Answer: Option D
Explanation:
A bristle is a part of a brush; a key is a part of a piano.
A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h1, h2 and h3 respectively. The average heat transfer coefficient for the cube is
Question: A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h1, h2 and h3 respectively. The average heat transfer coefficient for the cube is
[A].h1 + h2 + h3
(h1h2h3)1/3
none of these
[A].
[B].
[C].
[D].
Answer: Option D
Explanation:
No answer description available for this question.
Film coefficient is defined as the ratio of
Question: Film coefficient is defined as the ratio of
[A].thermal conductivity to the equivalent thickness of the film of fluid
temperature drop through the films of fluids to the thickness of film of fluids
thickness of film of fluid to the thermal conductivity
thickness of film of fluid to the temperature drop through the films of fluids
[A].
[B].
[C].
[D].
Answer: Option A
Explanation:
No answer description available for this question.
A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same heat loss and temperature drop, this can be replaced by a layer of diatomite earth of conductivity 0.14 W/mK and thickness
Question: A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same heat loss and temperature drop, this can be replaced by a layer of diatomite earth of conductivity 0.14 W/mK and thickness
[A].0.5 m
0.1 m
0.2 m
0.5 m
[A].
[B].
[C].
[D].
Answer: Option B
Explanation:
No answer description available for this question.
A composite slab has two layers of different materials with thermal conductivities k1 and k2. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be
Question: A composite slab has two layers of different materials with thermal conductivities k1 and k2. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be
[A].k1k2
k1 + k2
[A].
[B].
[C].
[D].
Answer: Option D
Explanation:
No answer description available for this question.
Which of the following would lead to a reduction in thermal resistance?
Question: Which of the following would lead to a reduction in thermal resistance?
[A].In conduction, reduction in the thickness of the material and an increase in thermal conductivity.
In convection, stirring of the fluid and cleaning the heating surface.
In radiation, increasing the temperature and reducing the emissivity.
all of the above
[A].
[B].
[C].
[D].
Answer: Option D
Explanation:
No answer description available for this question.
A steam pipe is to be lined with two layers of insulating materials of different thermal conductivities. For the minimum heat transfer,
Question: A steam pipe is to be lined with two layers of insulating materials of different thermal conductivities. For the minimum heat transfer,
[A].the better insulation must be put inside
the better insulation must be put outside
one could place either insulation on either side
one should take into account the steam temperature before deciding as to which insulation is put where
[A].
[B].
[C].
[D].
Answer: Option A
Explanation:
No answer description available for this question.