Question

Class 8 Science MCQ Questions of Synthetic Fibres and Plastics with Answers

Answer 1

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Practice Class 8 Science MCQ Questions Chapterwise

1. What is the other name for artificial silk?

(a) Nylon
(b) Rayon
(c) Acrylic
(d) Polyester

2. Which fibre is used as artificial wool?

(a) Acrylic
(b) Rayon
(c) Nylon
(d) Cotton

3. Polymers are made up of small units called

(a) layers
(b) molecules
(c) cells
(d) monomers

4. The strongest synthetic fibre is

(a) nylon
(b) rayon
(c) polyester
(d) acrylic

5. Which of the following is a natural fibre?

(a) Wool
(b) Nylon
(c) PVC
(d) Polythene

6. Melamine is

(a) thermoplastic polymer
(b) thermosetting polymer
(c) fibre
(d) elastomer

7. PET is a

(a) polyester
(b) polyamide
(c) nylon
(d) thermosetting polymer

8. Bakelite is an example of

(a) fibre
(b) elastomer
(c) nylon
(d) thermosetting polymer

9. Which of the following is correct about cellulose?

(a) Natural polymer
(b) Synthetic polymer
(c) Semi-synthetic polymer
(d) Natural monomer

10. Which of the following is non-biodegradable?

(a) Plastic
(b) Cotton
(c) Paper
(d) Left-over food

11. Which of the following is a natural fibre that comes from plants?

(a) Silk
(b) Cotton
(c) Rayon
(d) Polyester

12. Synthetic fibres prepared using raw materials of petroleum origin are called:

(a) Petrol
(b) petrochemicals
(c) petroleum
(d) disel

13. In which year was nylon made?

(a) 1931
(b) 1964
(c) 1948
(d) 1950

14. Common variety of polyester is

(a) terylene
(b) polymer
(c) viscose
(d) spinneret

15. The property of materials by which they can be molded into any shape is called

(a) conductivity
(b) elasticity
(c) plasticity
(d) none of these

16. Polywool is a mixture of which substances?

(a) Polyester + wool
(b) Polythene + wool
(c) Polycarbonate + wool
(d) Polyester + wool + cotton

17. The polymers in which smaller units are linked to each other in the straight arrangement are called

(a) cross-linked polymers
(b) linear polymers
(c) branched polymers
(d) none of the above

18. The synthetic plastic used for making insulation cover in electrical wires/cables is

(a) bakelite
(b) melamine
(c) polyvinylchloride
(d) polystyrene

19. The 4 R Principle is

(a) Reduce, Reuse, Recycle, Recover
(b) Remember, reduce, Recycle, Rejoice
(c) Repeat, Rejoice, recycle, reduce
(d) None of the above

20. Which of the following is a natural fibre obtained from plants?

(a) Cotton
(b) Teflon
(c) Rayon
(d) Ketone

21. Which of the following garbage is biodegradable:

(a) broken plastics things
(b) fruit peels
(c) cement
(d) iron wastes

22. Which of the following is obtained from hair of an animal:

(a) nylon
(b) Jute
(c) cotton
(d) wool

23. Which of the following is used in endoscopy-

(a) Optical fibres
(b) Glass fibres
(c) Glass wool
(d) None of these

24. Thermocole is made from -

(a) Polythene
(b) Polystyrene
(c) Perspex
(d) Teflon

25. The Material Similar To Silk In Appearance Is:

(a) Nylon
(b) Rayon
(c) Polyester
(d) Terylene

Answer 2

1. Answer: (b) Rayon

Explanation: Rayon is synthesized from wood pulp. Rayon resembles silk, so it is also known as artificial silk.

2. Answer: (a) Acrylic

Explanation: Acrylic is a man-made fibre. Acrylic is known as artificial wool or synthetic wool because it resembles wool. Acrylic is cheaper than natural wool and can be dyed in various colour.

3. Answer: (d) monomers

Explanation: Polymers are a class of synthetic substances composed of multiples of simpler units called monomers.

4. Answer: (a) nylon

Explanation: Nylon is a chemical polyamide polymer. It can be moulded into any shape and it is the strongest synthetic fibre.

5. Answer: (a) Wool

Explanation: Wool comes directly from the sheep coat. Since the source is naturally occurring, it is a natural fabric.

6. Answer: (b) thermosetting polymer

Explanation: Melamine formaldehyde is a thermosetting plastic and cannot be melted. Melamine formaldehyde resins are used as particleboard and plywood adhesives.

7. Answer:  (a) polyester

Explanation: PET (polyethylene terephthalate) is actually polyester. When PET is used for bottles, containers and other applications, it is called PET or PET resin. When PET is used as a fiber, it is typically called polyester.

8. Answer: (d) thermosetting polymer

Explanation: Bakelite is an example of a thermosetting polymer and also a type of phenol-formaldehyde polymers. These are obtained by the condensation reaction of phenol with formaldehyde in the presence of either an acid or a base catalyst.

9. Answer: (a) Natural polymer

Explanation: Cellulose fibers can be obtained from the bark, wood or leaves of plants, or from plant-based material. Cotton is a polymer of cellulose. It is made up of large number of glucose units.

10. Answer: (a) Plastic

Explanation: Substances that are not broken down by biological processes are said to be Nonbiodegradable pollutants. Nonbiodegradable pollutants are defined as pollutants that cannot be degraded by any biological actions. Plastic, asbestos and Polythene are examples of non-biodegradable pollutants. These pollutants are degraded very slowly in nature. 

11. Answer: (b) Cotton

Explanation: Cotton is the natural fiber which is obtained from the cotton plants. This is the epidermal hairs on the seeds of the crop plants. The fiber is composed of the natural cellulosic material which is used for the production of the cotton ropes from fibres and clothes.

12. Answer: (b) petrochemicals

Explanation: Synthetic fibres prepared using raw materials of petroleum origin are called petrochemicals.

13. Answer: (a) 1931

Explanation: Nylon was made in 1931 and Rayon was made in 1880.

14. Answer: (a) terylene

Explanation: Terylene is a synthetic polyester fibre produced by polymerizing ethylene glycol and terephthelic acid which is obtained from petroleum.

15. Answer: (c) plasticity

Explanation: The property of a body to regain its original shape when the deforming force is removed from it or to oppose the change in its original shape is called elasticity.Plasticity is the property of a material not to regain its original shape when the deforming force is removed, i e. a deforming force changes the shape of material permanently. Ductility is commonly defined as the ability of a body to be stretched into wires.

16. Answer: (a) Polyester + wool

Explanation: Polywool is a mixture of a synthetic fibre (polyester) and a natural fibre (wool). When polyester(synthetic fibre) is blended with wool(natural fibre) it forms Polywool. Mixture of polyester and wool. Polywool is a blended fibre formed by mixing fibres called polyester and wool.

17. Answer: (b) linear polymers

Explanation: The polymers in which smaller units are linked to each other in straight arrangement is called as​ Linear Polymer. Polymers are the macromolecule which are made of similar small subunits called monomers (base unit of polymer).

18. Answer: (c) polyvinylchloride

Explanation: PVC is an abbreviated form of polyvinyl chloride. The electrical characteristics of PVC such as electrical insulating properties or dielectric constant are excellent and hence, are used as insulating materials.

19. Answer: (a) Reduce, Reuse, Recycle, Recover

Explanation: 4R's principle means that use of non-environmental friendly substance should be reduced. They should be Reuse, Recycled and Recovered.

20. Answer: (a) Cotton

Explanation: Natural fibres are obtained from natural sources like plants animals. Examples of Natural fibres are silk, cotton, wool and jute.

21. Answer: (b) fruit peels

Explanation:Vegetable peels are completely biodegradable. Once decomposed, these peels get completely broken down and turn into compost or manure, which can be recycled in soil as fertilizer. The process in which veggie peels gets decomposed are completely natural and nontoxic for the environment.

22. Answer: (d) wool

Explanation: Wool is obtained from the animal sheep. It is fur of the animal sheep which is scraped out through a series of process and finally collected in the form of  yarns. Cotton and Jute are obtained from plants whereas, nylon is a synthetic material produced by combination of chemicals.

23. Answer: (a) Optical fibres

Explanation: Basically, a typical endoscope uses fiber optics, which allow for effective transmitting of light. In this technique (fiber optics) light is transmitted through a flexible fiber of glass (transparent) known as optical fiber(s). It is for this reason that the outer fiber is commonly referred to as the incoherent bundle.

24. Answer: (b) Polystyrene

Explanation: Thermocol slabs made of expanded polystyrene (EPS) beads.

25. Answer: (b) Rayon

Explanation: The material similar to silk in appearance is rayon. Since rayon resembles silk in appearance, it is called artificial silk.It is a man-made fibre obtained from a natural source wood pulp.

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