Here you get easy solutions of Lakhmir Singh and Manjit Kaur Science solution Chapter 3 . Ans: PET is a very popular form of polyester. Electric plugs/switches/plug boards are made of thermosetting plastics because they are bad conductors of electricity. Uses: It is used to make electrical goods, combs, fountain pens, buttons, plugs and switches. Bakelite continues to be used for wire insulation, brake pads and related automotive components, and industrial electrical-related applications. Substance made up of large number of smaller molecules (7) 4. 36) choose the thermoplastics and thermosetting plastic from the following: 38) Write the full form of PVC ? Is it thermoplastic or thermosetting plastic ? Bakelite is used for making electrical switches, handles of various utensils etc. Name the natural polymer of which cotton is made ? Ans: A Plastic is a synthetic materials which can be moulded into desired shape when soft and hardened to produced a durable article . D. Bakelite. 11) Name the form of polyester which is replacing materials like glasas and used for making bottles and jars . Ans: we should buy cotton shirts for summer. Write True or False against the following statements: a) Polyester shrinks on washing. Substance used as synthetic wool (7) 2. Biodegradable and non-biodegradable wastes should be separated and disposed off separately. Its help you to complete your homework. Bakelite has a high resistance to heat and chemicals and also has a low electrical conductivity due to which it is most commonly used for making electrical switches Bakelite is also used to make the handles of a variety of utensils. All Plastics have one common property what is it? Class 8 Science Chapter 3 MCQ with complete explanation are given below. Thatâs why synthetic fibres are become so popular. They do not decompose when left in open for a long period. 27) Explaining how, manufacturing of synthetic fibres is actually helping in the conservation of forests. It is also used to make jewelry articles and toys. 2) It is harder than other plastics. Prystal was a trade name used for a type of transparent Bakelite marketed by the American Catalin Corporation in a number of different colors. PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Q21: Why we prefer plastic containers for storage of items like water, milk, pickles, dry food? A polymer used … 1. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. The uses of rayon are:a) It is used to make curtains, table clothes, blankets, bed sheets, carpets etc.b) It is used to make apparels such as jackets, suits, etc. (ii) It is used ⦠(ii) It is used … 1)It is a poor conductor of heat. (a) Plastic bowls(b) Ballpoint pens(c) Telephone instruments(d) Electrical switchesAnswer:(a), Question 10.Which material is best suited for covering electric wires? A plastic used for making containers and carry bags (9) 3. We should reuse the plastic containers which comes with jams, pickels, oils and other packed food. It is a thermosetting polymer and Bakelite has high strength meaning it basically retains its form even after extensive molding. For example, Bakelite is a thermosetting plastic which is a poor conductor of heat and electricity. List its important properties and uses. Insulation of wires, brake pads, and some select automobile parts. Give three uses of polyester, and explain the reason for each use. Tabulate the data as shown in Table 3.1. Your email address will not be published. Ans: Thermosetting plastics are used for making those articles which may get too hot during use and are hard and rigid (so that they do not bend at all) so thatâs why electric switches, plugs and sockets made of thermosetting plastics. 8) Which synthetic fibre feels like wood and used as a substitute for wool ? c> Like synthetic fibres, plastic is also a POLYMER. 4. Bakelite stock is still manufactured and produced in sheet, rod and tube form for industrial applications in the electronics, power generation and aerospace industries, and under a variety of commercial brand names. Required fields are marked *. Arrange the threads in order of their increasing strength. Ans:   Plastic is a Non-Biodegradable product. Q7. 5. Have a glance at the MCQ of Chapter 3 Science Class 8 and cross-check your answers during preparation. Now coming to the uses of Bakelite, since this element has a low electrical conductivity and high heat resistance it can be used in manufacturing electrical switches and machine parts of electrical systems. Phenolic resins are also extensively used as adhesives … NCERT Solutions Class 10 Science (Physics,Chemistry, Biology). Bakelite also acted as a binder for textiles, sawdust, and paper, forming a wide range of composites including Formica laminates. D.SHORT-ANSWER QUESTIONS (TYPE II): Answer in about 30 words. They cannot be decomposed by bacteria and so are no biodegradable in nature. Multiple Choice Questions Question. Name of the popular polyester is terylene. (i) A material which does not get decomposed by natural processes. 35) Explaining why plastic containers are preferred for storing food ? Ans: Clothes made of synthetic fibres are not suitable for wearing during hot summer. It is used for making saucepan handles. 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