NCERT Class VIII Science Solution: Chapter 3-Synthetics Fibres and Plastics Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

Glide to success with Doorsteptutor material for CBSE/Class-8 : get questions, notes, tests, video lectures and more- for all subjects of CBSE/Class-8.

Question 7:

Explain why the following are made of thermosetting plastics.

  1. Saucepan handles.
As Showing Images is a Result for Saucepan Handles
  1. Electric plugs/switches/plug boards.
As Showing Images is a Result for Electrical Plugs

Answer:

  1. Melamine (a thermosetting plastics) resists fire and can tolerate heat better than other plastics. So, it is used for making Saucepan handles, which resist fire.
  2. Bakelite (a thermosetting plastics) is a poor conductor of heat and electricity. So, it is used for making Electric plugs, switches, plug boards, etc.

Question 8:

Categories 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, and plastic covering on electrical wires, plastic chairs and electrical switches.

Answer:

Plastic toys, carry bags, ball point pens, plastic bowls, plastic covering on electrical wires and plastic chairs can be recycled as these are the thermoplastic.

Telephone instruments, cooker handles and electrical switches cannot be recycled as these are thermosetting plastics.

Frequently Asked Questions (FAQs)

  • Which of the following cannot be recycled (a) wooden toys (b) polyamide (c) cooker handle (d) plastic chair

    ( - kk...@ on )

    1 Answer

    Plastic toys can be recycled but 100 % wooden toys often can՚t be recycled because of the paints and varnishes. Some other recyclable materials are cooker handles, ball point pen, plastic chairs, electric wire.

    - kk...@ on

  • Class 9 Science lectures

    ( - ho...@ on )

    1 Answer

    You can visit Examrace YouTube channel for important lectures of Science, one of the lectures of class 8 has been shared below

    Class 8 Chapter 2 Science Lecture

    - ho...@ on

Developed by: