Check the below Online Education NCERT MCQ Questions for Synthetic Fibres and Plastics Class 8 Extra Questions and Answers Science Chapter 3 Pdf free download. https://ncertmcq.com/extra-questions-for-class-8-science/
Online Education for Class 8 Science Chapter 3 Extra Questions and Answers Synthetic Fibres and Plastics
Synthetic Fibres And Plastics Class 8 Questions Answers Question 1.
Name a synthetic fibre which is used in making cheap and durable woollen clothes.
Answer:
Acrylic.
Synthetic Fibres And Plastics Class 8 Question 2.
Give one-word answer for the following :
Plastic which gets deformed easily on heating and can be easily bent.
Answer:
Thermoplastic.
Synthetic Fibres And Plastics Class 8 Questions Answers Pdf Question 3.
Complete the sentence: Rayon is not a synthetic fibre because
Answer:
it is obtained from a natural source.
Class 8 Synthetic Fibres And Plastics Question 4.
When was nylon made?
Answer:
Nylon, a man-made fibre, was made in 1931.
Extra Questions For Class 8 Science With Answers Question 5.
Which one is stronger: a nylon wire or a steel wire?
Answer:
Nylon wire.
Synthetic Fibres Class 8 Question 6.
What is the disadvantage of synthetic fibre?
Answer:
The synthetic fabric melts on heating, which is a disadvantage of this fabric.
Synthetic Fibres And Plastics Question 7.
From which material, all synthetic fibres are prepared?
Answer:
Synthetic fibres are prepared from petrochemicals.
Cbse Class 8 Synthetic Fibres And Plastics Question 8.
What are manufactured from thermoplastics?
Answer:
Toys, combs, car grills and various types of containers are manufactured from thermoplastics.
Plastic And Environment Class 8 Question 9.
What are the characteristics of plastic due to which it is used to manufacture variety of articles?
Answer:
- They have lightweight,
- lower price,
- good strength, and
- are easy to handle.
Ncert Science Book Class 8 Extra Questions With Answers Question 10.
Why is plastic covering used in electric wires?
Answer:
It is because plastic is a poor conductor of electricity.
Learn Insta Class 8 Science Extra Questions Question 11.
Why are handles of frying pans, cookers are made of plastic material?
Answer:
It is so because plastic material is poor conductor of heat.
Fibres And Plastics Class 8 Question 12.
Why is plastic not environment friendly?
Answer:
Since plastic takes several years to decompose, it is not environment friendly.
Synthetic Fibres And Plastics Questions Question 13.
Explain, why the handles of cooking utensils, electric plugs, switches or plugboards are made of thermosetting plastics?
Answer:
The handles of cooking utensils, electric plugs, switches or plugboards are made of thermosetting plastics because :
- Thermosetting plastics cannot be softened by heating.
- They are poor conductors of heat and electricity.
- They resist fire and can tolerate heat.
Ncert Class 8 Science Chapter 3 Synthetic Fibres And Plastics Question 14.
What are the characteristic properties of synthetic fibres, due to which they are used abundantly?
Answer:
Synthetic fibres possess the following unique characteristics :
- They dry up soon,
- They are durable,
- They are less expensive,
- They are readily available, and
- They are easy to maintain.
Synthetic Fibres And Plastics Class 8 Hots Questions Question 15.
What is melamine? What are its uses?
Answer:
Melamine is a versatile thermosetting plastic. It resists fire and can tolerate heat better than other plastics. It is used for making floor tiles, kitchenware and fabrics which resists fire.
Synthetic Fibres And Plastics Class 8 Extra Questions Question 16.
What is the characteristic property of plastic due to which it is used to make containers to store different materials?
Answer:
Plastics do not react with water and air and, therefore, they are non-corrosive in: nature. That is why, the containers made of plastics are used for storing various kinds of materials, including many chemicals.
Synthetic Fibres And Plastics Class 8 Extra Questions Answers Question 17.
Write a brief note on Teflon.
Answer:
Teflon is a non-stick plastic used as non-stick coating in cookwares. Because of its toughness, it is also used as tape for sealing purposes.
Ncert Science Class 8 Chapter Synthetic Fibres And Plastics Question 18.
Write a note on cross-linked plastic.
Answer:
Cross-linked plastic is that plastic in which its units possess cross-linked arrangements. The cross-linked plastics are available in all possible shapes and sizes. This is due to the fact that plastics are easily mouldable, i.e., plastic can be shaped in any form. That is why, various types of containers like water tanks, water jugs, buckets, mugs, etc. are made of it arid used in day-to-day life.
Synthetic Fibres And Plastics Class 8 Answers Question 19.
Write a short note on the plastic in healthcare industry.
Answer:
Plastics find extensive use in the healthcare industry. Some examples of their use in healthcare are in packaging of medicines, threads used for stitching wounds, syringes, gloves, a number of medical instruments, etc.
Chapter 3 Synthetic Fibres And Plastics Class 8 Question 20.
Write any five characteristics of synthetic fibres.
Answer:
The characteristics of synthetic fibres are :
- Synthetic fibres are cheaper than natural fibre.
- Synthetic fibres are stronger than natural fibre.
- Synthetic fibres are more durable than natural fibre.
- Synthetic fabrics are dried up in less time.
- Synthetic fibres are easy to maintain and wash.
- Synthetic fibres are readily available and easy to maintain.
Question 21.
Write a note on rayon.
Answer:
Natural silk from silkworms was discovered in China and was kept as a closely guarded secret for a long time. Silk was a costly fabric. But, as its texture was beautiful, it fascinated everybody. So, people began to think of preparing silk artificially.
Towards the end of the nineteenth century, scientists were successful in obtaining a fibre having the properties similar to that of silk. Such a fibre was obtained by chemical treatment of wood pulp. This fibre was called rayon or artificial silk. Although rayon is obtained from a natural source, wood pulp, yet it is a man-made fibre. It is cheaper than silk but can be woven like silk fibres. It can also be dyed in a wide variety of colours.
Question 22.
What are renewable and non-renewable sources of energy? What will happen if all the non-renewable resources get exhausted?
Answer:
Renewable sources of energy :
The sources of energy, which are being produced continuously in nature and are inexhaustible, are called renewable sources of energy. These sources of energy can be used again and again, endlessly. They will never get exhausted. For example, wind, sunlight.
Non-renewable sources of energy :
The sources of energy, which have accumulated in nature over a very, very long time and cannot be quickly replaced when exhausted, are called non-renewable sources of energy, e.g., coal.
If all non-renewable sources of energy get exhausted, we will have to depend on renewable sources of energy. More and more alternative sources will have to be developed.
Question 23.
(a) You have to buy clothes to wear in summer. You will prefer to buy cotton clothes or clothes made of synthetic material. Give reason for your answer.
(b) Which material is better for making umbrellas and why?
Answer:
(a) I will prefer to buy cotton clothes over synthetic clothes. This is because cotton clothes absorb more sweat than synthetic clothes. I will comfortable and cool in cotton clothes than synthetic clothes.
(b) Synthetic cloth is better for making an umbrella because
- Synthetic fibre is more durable.
- Synthetic fibre is stronger.
- Synthetic fibre absorbs less water.
- Synthetic fibre is lightweight as compared to cotton cloth.
Question 24.
“Even though plastics are very useful, they are not environment friendly.” Justify the statement.
Answer:
Even though plastics are very useful and have vital applications in our daily life but they are not environmentally friendly because :
(а) The plastics are not bio-degradable and take several years to decompose. It causes environmental pollution.
(b) The burning process in the synthetic material is quite slow and it does not get completely burnt easily. In the process, it releases lots of poisonous fumes into the atmosphere causing air pollution.
Multiple Choice Questions (MCQs)
1. Rayon is known as
(a) artificial silk
(b) both
(c) regenerated fiber
Answer:
(a) artificial silk.