Related Questions

The solid brick shown is made of small square shaped bricks of side 1. when the large brick is disassembled into its component small bricks. the total surface area of all the small bricks is how much greater than the surface area of the large brick?
A 32
B 40
C 60
D 72
Thermal conductivity based continuous flue gas analyser makes use of varying thermal conductivity of the constituents of flue gases. Which of the following constituents of flue gases has the maximum thermal conductivity?
A CO2
B N2
C O2
D CO
Refractory bricks having high thermal conductivity is desirable, when it is to be used in the
A L.D. converter
B Blast furnace
C Rotary kiln
D Recuperator
High porosity refractory bricks have
A Poor resistance to the peneration of molten slag, metal & flue gases
B Poor heat conductivity & low strength
C Better thermal spalling resistance
D All of the above
Thermal conductivity of refractory bricks
A Increases with decrease in porosity
B Decreases with decreases in porosity
C Is independent of its porosity and is maximum for insulating bricks
D Increases with the amount of air entrapped in pores
Thermal diffusivity of a refractory brick is high, when its __________ is high.
A Density
B Specific heat
C Thermal conductivity
D None of these
Refractory bricks having lower porosity have
A High insulating properties
B Low heat capacity
C Low thermal conductivity
D Greater strength
Low thermal conductivity of heat insulating materials is due to its
A Dense structure
B High proportion of air space
C High specific heat
D None of these
A red house is built from red bricks . A blue house is built from blue bricks. A white house is built from white bricks. Then what is a greenhouse made from ?
A green bricks
B wood
C glass
D steel
For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally
A Decreases
B Increases
C Remains unchanged
D Increases exponentially

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