Calcination of iron ores is done
To remove moisture
To remove carbonic acid
By roasting in heaps
All the above
Correct Answer :
D. All the above
Related Questions
Pick up the correct statement from the following:
Solder material is an alloy which melts at a temperature above 400°C
Brazing is done at temperature above 600°C to 1100°C
Brazing joint is stronger than the solder joint
All the above
Index number expressing the relative sizes of both coarse and fine aggregates, is called
Proportioning of aggregates
Fineness modulus
Grading of aggregates
None of these
Duco paints are
Plastic paints
Cellulose paints
Emulsion paints
Oil paints
Pick up the correct statement from the following:
Lime is available in Free State
Lime is available by dissolving calcium carbonate in water
Lime is available by calcining calcium carbonate at 900°C
Lime is nothing but calcium chloride
A first class brick when immersed in cold water for 24 hours should not absorb water more than
15 %
20 %
22 %
25 %
Which of the following gradients exerts maximum influence on properties of steel?
Iron
Carbon
Manganese
Sulphur
The softest rock is
Marble
Diamond
Talc
Quartz
Putty is
Made with finely powdered chalk and linseed oil
Used for fixing glass panes
Softened by a solution of pearl ash and quick-lime soaked in water
All the above
Initial setting time of cement for asbestos cement products should be not less than
30 minutes
50 minutes
75 minutes
90 minutes
Fibre boards can be
Distempered
Painted
Painted and distempered
Used for furniture
Which of the following bricks are used for lining of furnaces?
Over-burnt bricks
Under-burnt bricks
Refractory bricks
First class bricks
Lime concrete is generally used for
Wall foundations
Flooring at ground level
Both (A) and (B)
Neither (A) nor (B)
Cast iron contains carbon approximately
1.5% to 5.5%
0.05% to 1.75%
0.250 %
None to these
The most fire resistant paints are:
Enamel paints
Aluminium paints
Asbestos paints
Cement paints
The commonly used base for iron and steel work, is
Red lead
Zinc white
White lead
Titanium white
A rock contains only one mineral. It is called
Homogeneous
Non-homogeneous
Monomineralic
Polymineralic
Portland cement manufactured from pure white chalk and clay but free from iron-oxide, is known as
Quick setting cement
Rapid hardening cement
White cement
Low heat Portland cement
Bitumen emulsion is
A liquid containing bitumen in suspension
A paint
Used as anti-corrosive paint
All the above
Which of the following pairs gives a correct combination of the useful and harmful constituents respectively of a good brick earth?
Lime stone and alumina
Silica and alkalies
Alumina and iron
Alkalies and magnesium
Pick up the correct statement from the following:
Melamine is obtained from calcium carbide
Formaldehyde is prepared synthetically from methane
The melamine when reacted with formaldehyde forms the melamineformaldehyde resin
All the above
Pick up the correct statement from the following:
The percentage of absorption for firebricks varies from 5 to 10
The percentage of silica in silica bricks is to the extent of about 95 to 97 percent
Roughly 1 to 2 percent of lime in silica bricks is added to act as binding material
All the above
Bullet proof glass is made of thick glass sheet sandwiched by a layer of
Steel
Stainless steel
High test plastic
Chromium plate
Asbestos
Is an excellent insulator for heat and electricity
Is fire-proof and acid proof
Has sp. gravity equal to 3.10
All the above
German silver is an alloy of
Zinc, lead and nickel
Silver, gold and lead
Copper, nickel and zinc
Copper, brass and zinc
Seasoning is
A process of removing sap
Creosoting
Painting with sodium silicate
Coating with tar
For the manufacture of plywood, veneers are placed so that grains of adjacent veneers
Run at right angles
Parallel
Inclined at 45°
Inclined at 60°
For high grade instruments the steel preferred to, is
Cast steel
Bessemer steel
Mild steel
Whitworth compressed steel
When a brick is immersed in water for 24 hours and then dried, if
No grey or white deposits appear on the surface, the brick is free from soluble salts
10 percent surface is covered with grey or white deposits, the brick has slight efflorescence
50 percent surface is covered with grey or white deposits, the brick has serious efflorescence
All the above
The proportions of charcoal, saltpetre and sulphur in gun powder by weight, are respectively:
15, 75, 10
75, 10, 15
10, 15, 75
10, 75, 15
Pick up the correct statement from the following:
Corrugated sheet iron is made by passing plain sheets between grooved rollers
Strength and stiffness of corrugated sheets are considerably increased
Corrugated sheets are generally used on slanting roofs
All the above