Question

The windscreen of cars, airplanes etc. is made up of-
A.Hard glass
B.Safety glass
C.Lead glass
D.Soda glass

Answer 1

Hint:Glass is a transparent or translucent material which is also hard and brittle. It is used in many areas like construction of buildings, house wares and telecommunications. There are many types of glass based on the variety of chemical composition and quantity of the materials used in making them.

Complete step-by-step answer:Hard glass- is also called potash glass as it is prepared by fusion of potassium carbonate, calcium carbonate and silica. It is very hard and it has a high melting point as its name suggests. It is also more resistant to the action of acids. Its uses are-
In making laboratory apparatus which can be used during experiments.
Safety glass- is like a sandwich in which a thin sheet of plastic is sandwiched between two layers of glass by using appropriate adhesive on both sides. Then by applying pressure and heat, it forms a single sheet known as safety glass. It is called safety glass because it cannot be broken easily even by hitting with heavier objects. It is used for-
For making windscreens of vehicles like cars and transport like trains and aeroplanes.
For making bullet proof jackets for security purposes.
Lead Glass-is made by fusion of potassium carbonate, silica and lead oxide. Due to the presence of lead, it is called lead glass. It is very lustrous. It is used for-
In making expensive products made by glass due to its shining property.
Soda glass- is made by fusion of sodium carbonate, calcium carbonate and silica. Due to the presence of sodium carbonate (sodium ash), it is called soda glass. Since it becomes soft after heating it is also called soft glass. It is used for following purposes-
In making mirrors, window panes and glass tumblers.
In making bottles, dishes and electric bulbs.

The correct answer is option B.

Note:Safety glass is easy to manufacture as its raw materials are easily available so it is also cheap. Besides these, there are other types of glasses like-
Pyrex glass- used in making flask and beakers due to high heat withstanding ability. The utensil used in the microwave ovens in our houses is made of this glass.
Photochromic glass- It is used to make cameras, goggles and spectacles as it has the property of becoming dark colored when it is exposed to sunlight due to presence of silver bromide layer over it.