681. Percentage content of silica in window glass, is
A. 40 to 45
B. 50 to 55
C. 60 to 65
D. 70 to 75.

682. Ground glass
A. is made by grinding its one side
B. is made by melting powdered glass paints surface
C. is used for getting light without transparency
D. all the above.

683. Bullet proof glass is made of thick glass sheet sandwiched by a layer of
A. steel
B. stainless steel
C. high test plastic
D. chromium plate.

684. Dextrine is
A. animal glue
B. starch glue
C. albumin glue
D. rubber based adhesive

685. Putty is
A. made with finely powdered chalk and linseed oil
B. used for fixing glass panes
C. softened by a solution of pearl ash and quick-lime soaked in water
D. all the above.

686. Bitumen in
A. solid state, is called asphalt
B. semi fluid-state, is called mineral tar
C. fluid state, is called petroleum
D. all the above.

687. Mastic asphalt is
A. water proof
B. fire proof
C. elastic
D. all the above.

688. According to ISI, bitumen is classified into
A. 2 grades
B. 4 grades
C. 6 grades
D. 10 grades.

689. Bitumen is generally obtained from
A. organic material
B. synthetic material
C. petroleum product
D. coal.

690. Bitumen may be dissolved in
A. carbondioxide
B. water
C. sodium chloride
D. carbon disulphide

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