3. Synthetic Fibres And Plastics Science class 8 in English Medium ncert book solutions Additional Questions With Solutions

Additional Questions With Solutions

Que: Name the sources of fibres, by which are fabrics made?

Ans: Natural fibres and artificial fibres.

Que: Name the some natural fibres.

Ans: (i) Cotton (ii) wool (iii) silk

Que: Name some artificial or synthetic fibres.

Ans: (i) Rayon (ii) Nylon (iii) polyester and (iv) Acrylic

Que: What are synthetic fibres?

Ans: The fibres which are made by the human beings is called synthetic fibres. As Rayon, Nylon, polyester and Acrylic

Que: What is polymer?

Ans: The small units of fibres which is actually a chemical substance, such many small units combine to form a large single units is called a polymer. Ex. Cellulose, Nylon, polyester etc.

Que: Name a natural polymer.

Ans: Cellulose.

Que: Write the property of Rayon.

Ans: Rayon is the man-made fibre which is obtained by chemical treatment of wood pulp.

Properties:

(i) It is cheaper than silk.

(ii) It can be woven like silk fibre.

(iii) It can also be dyed in a wide variety of colours.

Que: Write the three property of Nylon.

Ans: Nylon is also man-made fibre. It was prepared from coal, water, and air. Properties;

(i) It is strong, elastic and light.

(ii) It is lustrous and easy to wash.

Que: Write the use of nylon?

Ans: Nylon is used for making parachutes and ropes for rock climbing. A nylon thread is an actually stronger than a steel wire. It is also used for making cloth.

Que: Name some synthetics fibers which are used for wearing.

Ans: Polyester and Terylene.

Que: What is PET and write its uses?

Ans: PET is a very familiar form of polyester. It is used for making bottles, utensils, films, wires and many other useful products.

Que: What is acrylic?

Ans: The wool which are actually not made from natural wool. These are prepared from another type of synthetic fibre called acrylic.

Que: What are thermoplastics?

Ans: Such plastic which gets deformed easily on heating and can be bent easily are known as thermoplastics.

Que: What are thermosetting plastics?

Ans: Some plastics which when moulded once, cannot be softened by heating. These are called thermosetting plastics.

Que: Give examples to show that plastics are noncorrosive in nature.

Ans: The plastic is noncorrosive in nature because of it doesn’t react to air and water.