NCERT Class VIII Science Solution: Chapter 3-Synthetics Fibres and Plastics Part 1

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Question 1:

Explain why some fibres are called synthetic.

Answer:

Some fibres which are not natural (man-made fibres) called synthetic because they are made by chemical processing of petrochemicals. The synthetic fibres are made up of very large units called polymers. Some of the synthetic fibres are rayon, nylon and acryl on.

As showing images is a result for synthetic fibres

Result for Synthetic Fibres

As showing images is a result for synthetic fibres

Question 2:

Mark (√) the correct answer:

Rayon is different from synthetic fibres because.

  1. It has a silk like appearance.

  2. It is obtained from wood pulp.

  3. Its fibres can also be woven like those of natural fibres.

Answer: B

Rayon is a cloth fibre which resembles silk on touching. As wood pulp or the purified cellulose is used to make it, it is not exactly defined as pure synthetic fibre.

It can be defined as Semi-Synthetic fibre. And it is called synthetic fibre because the wood pulp is modified into the yarn through certain non-natural processes.

Question 3:

Fill in the blanks with appropriate words:

  1. Synthetic fibres are also called ______ or _______ fibres.

  2. Synthetic fibres are synthesized from raw material called ________.

  3. Like synthetic fibres, plastic is also a __________.

Answer:

  1. Synthetic fibres are also called man-made or artificial fibres.

  2. Synthetic fibres are synthesized from raw material called petrochemicals.

  3. Like synthetic fibres, plastic is also a polymer.