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NCERT solutions Science Class 8 chapter 3 Synthetic Fibres and Plastics

Chapters

NCERT Science Class 8

Science Textbook For Class 8

Chapter 3 - Synthetic Fibres and Plastics

Pages 41 - 42

Explain why some fibres are called synthetic.

Q 1 | Page 41

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

Q 2 | Page 41

Fill in the blanks with appropriate words.

Synthetic fibres are also called ______ or _______ fibres.

Q 2.1 | Page 41

Fill in the blanks with appropriate words.

Synthetic fibres are synthesised from raw materials called ______

Q 3.2 | Page 41

Fill in the blanks with appropriate words.

Like synthetic fibres, plastic is also a _______

Q 3.3 | Page 41

Give examples which indicate that nylon fibres are very strong.

Q 4 | Page 41

Explain why plastic containers are favoured for storing food.

Q 5 | Page 41

Explain the difference between thermoplastic and thermosetting plastics.

Q 6 | Page 41

Explain why the following are made of thermosetting plastics.

Saucepan handles

Electric plugs/switches/plug boards

Q 7 | Page 41

Categorize the materials of the following products 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.

Q 8 | Page 41

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

Q 9 | Page 41

Give examples to show that plastics are non-corrosive in nature.

Q 10 | Page 41

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

Q 11 | Page 41

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

Q 12 | Page 41

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

  A   B
1 Polyester a Prepared by using wood pulp
2 Teflon b Used for making parachutes and stockings
3 Rayon c Used to make non-stick cookware
4 Nylon d Fabrics do not wrinkle easily
Q 13 | Page 42

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

Q 14 | Page 42

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

Q 15 | Page 42

NCERT Science Class 8

Science Textbook For Class 8
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