PIS BARODA STD-8

Synthetic Fibres and Plastics 1.   Why is acrylic more popular than wool? 2.   What is the difference between natural and synthetic fibres? 3.   Write a few characteristics of synthetic fibres. 4.   What is 4R principle? 5.   What are biodegradable and non-biodegradable materials? 6.   What are the disadvantages of plastics? 7.   Why is it convenient to store plastic containers than metals? 8.   What are the uses of nylon? 9.   What do you mean by synthetic fibres? 10.   Why is it advisable to not wear synthetic clothes while working near fire?

Class 8 Synthetic Fibres Plastics Question answers Chapter 3 Synthetic Fibres & Plastics Multiple Choice Questions (MCQs) Which of the following is not a man-made material? (a) Plastic (b) Wood (c) Cement (d) Nylon Which synthetic fibre is called artificial silk? (a) Acrylic (b) Nylon (c) Polyester (d) Rayon Which of the following is a bad conductor of electricity? (a) Plastic (b) Copper (c) Steel (d) Brass What of the following is used for making stockings and parachutes? (a) Bakelite (c) Wool (c) Nylon (d) Cotton The synthetic polymer which can be used as a substitute for wool for making sweaters and shawls etc. are : (a) Nylon (b) Terylene (c) Polyester (d) Acrylic Plastic which cannot be melted and moulded repeatedly? (a) Thermoplastic (b) PET (c) Thermosetting plastic (d) Polyethylene Which of the following is not a thermoplastic? (a) Polythene (b) Nylon (c) Melamine (d) PVC The plastic us...

Revision Notes on Synthetic Fibres and Plastics Fabrics are made by weaving fibres (or threads) obtained from natural or artificial sources. They can be of two types: What are Synthetic Fibres? What is a synthetic fibre made up of? A synthetic fibre,  as well as plastic,  is made up of a chain of small units (called  Monomers ) which combine to form polymers. Monomers:  A monomer is a single molecule that can bond with other identical molecules to form polymers through a process called  Polymerization . Polymers:  Polymer is a Greek word in which 'poly' means 'many' and 'mer' means units. Hence, polymers are large molecule made up of several molecules (or monomers) linked together. Example of Polymers: ·          All synthetic fibres, such as Rayon and Nylon, are polymers. ·          Polymers are also found in Nature. ‘Cotton’ is a polymer called ‘ ...