Related Questions

An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture?
A Cork
B Saw dust
C Sand
D Chemically prepared foam
The ratio of momentum diffusivity to thermal diffusivity is the __________ number.
A Prandtl
B Nusselt
C Stanton
D Grashoff
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
If mass diffusivity in a mixture is equal to the thermal diffusivity, then the Lewis number is
A 0
B 1
C > 1
The method of moving each brick through a small horizontal distance before it is finally laid in any brick wall and pressing it by means of brick hammer, is known as
A Troweling
B Laying
C Grouting
D Placing
If a refractory contains high content of silicon, it means refractory is
A Acidic
B Basic
C Neutral
D Brittle
Dry mix hydraulic compositions of refractory aggregates with suitable bonding materials are called refractory
A Mortars
B Cements
C Castables
D None of these
If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process'. The diffusivity under this condition is called 'Knudsen diffusivity', which is affected by the
A Pressure
B Temperature
C Both A & B
D Neither A nor B
Addition of zircon to silica refractory brick improves its
A Crushing strength
B Resistance to slag attack
C Neither A nor B
D Neither A nor B
Thermal diffusivity of a substance is proportional to (where, k = Thermal conductivity)
A $$\frac{1}{{\text{k}}}$$
B k
C k2
D $$\frac{1}{{{{\text{k}}^2}}}$$

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