Study Materials: ncert solutions

Our ncert solutions for Solutions 3. Synthetic Fibres And Plastics - Text Book Exercise | Class 8 Science - Toppers Study is the best material for English Medium students cbse board and other state boards students.

Solutions ⇒ Class 8th ⇒ Science ⇒ 3. Synthetic Fibres And Plastics

Solutions 3. Synthetic Fibres And Plastics - Text Book Exercise | Class 8 Science - Toppers Study

Topper Study classes prepares ncert solutions on practical base problems and comes out with the best result that helps the students and teachers as well as tutors and so many ecademic coaching classes that they need in practical life. Our ncert solutions for Solutions 3. Synthetic Fibres And Plastics - Text Book Exercise | Class 8 Science - Toppers Study is the best material for English Medium students cbse board and other state boards students.

Solutions 3. Synthetic Fibres And Plastics - Text Book Exercise | Class 8 Science - Toppers Study

CBSE board students who preparing for class 8 ncert solutions maths and Science solved exercise chapter 3. Synthetic Fibres And Plastics available and this helps in upcoming exams 2022-2023.

You can Find Science solution Class 8 Chapter 3. Synthetic Fibres And Plastics

  • All Chapter review quick revision notes for chapter 3. Synthetic Fibres And Plastics Class 8
  • NCERT Solutions And Textual questions Answers
  • Extra NCERT Book questions Answers
  • Importatnt key points with additional Assignment and questions bank solved.

Chapter 3 Science class 8

Text Book Exercise class 8 Science Chapter 3. Synthetic Fibres And Plastics

3. Synthetic Fibres And Plastics

| Text Book Exercise |

Solutions 3. Synthetic Fibres And Plastics - Text Book Exercise | Class 8 Science - Toppers Study


Exercise


Q1. Explain why some fibres are called synthetic?

Answer:

Since man-made fibers are obtained by the synthetic of petrochemicals, they are called synthetic fibres.

Q2. Mark ( ) the correct answer:

Rayon is different from synthetic fibres because.

(a) it has a silk like appearance.

(b) it is obtained from wood pulp.

(c) its fibres can also be woven like those of natural fibres.

Answer:

 (b) it is obtained from wood pulp.

Q3. Fill in the blanks with appropriate words:

(a) Synthetic fibres are also called ______ or _______ fibres.

(b) Synthetic fibres are synthesised from raw material called ________.

(c) Like synthetic fibres, plastic is also a ________.

Answer:

(a) artificial, man-made.

(b) polymer.

(c) petrochemicals.

Q4. Give examples which indicate that nylon fibres are very strong. 

Answer:

They are used to make Parachutes,and ropes for rockclimbing. 

Q5. Explain why plastic containers are favoured for storing food.

Answer:

The three main advantages of using plastic containers for storing food are: 

(I) plastic has light weight, 

(II) good strength,and 

(III) are easy to handle. 

Q6. Explain the difference between the thermoplastic and thermosetting plastics.

Answer:  

Thermoplastics Plastic:

(I) These are the plastics which gets deformed easily on heating and can be bent easily.

Examples: Polythene and P.V.C. 

(II) These are used for manufacturing toys, combs, car grills and various types of containers.

Thermosetting plastics:

(I) These are the plastics which when moulded once,cannot be softened by heating.

Examples: Bakelite and melamine.

(ii) (a) Bakelites are used for making electrical switches,handles of various utensils,etc.

(b)Melamines are used for making floor tiles,kitchen-wares and fabrics,which resist fire.

Q7. Explain why the following are made of thermosetting plastics.

(a) Saucepan handles

(b) Electric plugs/switches/plug boards

Answer

:(a) As baklite (a kind of thermosetting plastic) is a bad conductor of heat, therefore, saucepan handles are made up of it.

(b) Bakelite (a kind of thermosetting plastics) is also a bad conductor of electricity, so these electricity appliances are made up of it.

Q8. Categorise the following  materials   into ‘can be recycled’ and ‘cannot be recycled’: Telephone instruments, plastic toys, cooker handles, carry bags, ball point pens, plastic bowls, plastic covering on electrical wires, plastic chairs, electrical switches.

Answer:

(i) Can be recycled: Telephone instruments, plastics toys, ball point pens, plastics bowls.(As these are thermoplastics, so these can be recycled).

(II) Cannot be recycled: Cooker handles,carry bags, plastic covering on electric wire, plastic chairs, etc. (As these are thermosetting plastic, these cannot be recycled). 

Q9. Rana wants to buy shirts for summer. Should he buy cotton shirts or shirts made from synthetic material? Advise Rana, giving your reason?

Answer:

I would advise Rana to buy cotton shirts absorb the sweat and thus endorse cooling, Besides, they also provide aeration.

Q10. Give examples to show that plastics are noncorrosive in nature?

Answer:

The plastics are noncorrosive, that is, do not react or do not have chemical reaction with the materials contained in it. That is why many containers like bucket, mug, water bottles, food containers are made by using plastics. 

Q11. Should the handle and bristles of a tooth brush be made of the same material? Explain your answer?

Answer:

The handles and bristles of a toothbrush should be made of a material which has light weight, good strength and is hygine. But the bristles should be soft enough so that they do not harm gums while the handle should be quite stuff so that it may not get bent while brushing. 

Q12. ‘Avoid plastics as far as possible’. Comment on this advice?

Answer:

Since plastic takes several years to decompose, it is not decompose, it is not enviorment friendly. It causes enviormental pollution. Besides, its burning releases lots of poisoms fumes into the atmosphere causing air pollution. So, we should aviod the use of plastic as far as possible.

Q13. Match the terms of column A correctly with the phrases given in column B.

(i) Polyester     (a) Prepared by using wood pulp

(ii) Teflon        (b) Used for making parachutes and stockings

(iii) Rayon       (c) Used to make non-stick cookwares

(iv) Nylon        (d) Fabrics do njot wrinkle easily.

Answer:    

(i)-(d) (ii)-(c) (iii)-(a) (iv)-(b)

Q14. ‘Manufacturing synthetic fibres is actually helping conservation of forests’. Comment?

Answer:

 

Q15. Describe an activity to show that thermoplastic is a poor conductor of electricity?

used to make nonstick cookwares 

Select Your CBSE Classes

Important Study materials for classes 06, 07, 08,09,10, 11 and 12. Like CBSE Notes, Notes for Science, Notes for maths, Notes for Social Science, Notes for Accountancy, Notes for Economics, Notes for political Science, Noes for History, Notes For Bussiness Study, Physical Educations, Sample Papers, Test Papers, Mock Test Papers, Support Materials and Books.

 

 

Mathematics Class - 11th

NCERT Maths book for CBSE Students.

books

Study Materials List:

Solutions ⇒ Class 8th ⇒ Science
1. Crop Production And Management
2. Microorganisms : Friend And Foe
3. Synthetic Fibres And Plastics
4. Materials : Metals And Non-Metals
5. Coal And Petroleum
6. Combustion And Flame
7. Conservation of Plants And Animals
8. Cell - Structure and functions
9. Reproduction in animals
10. Reaching the age of adolescence
11. Force And Pressure
12. Friction
13. Sound
14. Chemical Effects of Electric Current
15. Some Natural Phenomena
16. Light
17. Stars And The Solar System
18. Pollution of Air and Water

Topper's Study

New Books