CBSE Class 8 Answered
(1) Why are natural fibres preferred over synthetic fibres?
(2) State the property of thermosetting plastics?
(3) Give reason for the following
(a) polyester is not suitable for summer
(b) use of plastic today is a matter of concern
(c) nylon derives its name from two cities
(d) plastic is known to have a variety of properties
(e) bakelite and melamine can maintain their shape and size even at high temperature
(f) burning cotton smells like burning paper,and burning wool smells like burning hair.
Asked by gspublicschool | 26 May, 2019, 07:30: PM
Expert Answer
Ans.1.
- Synthetic fibres are very strong and more durable.
- They absorb very little water and dry up quickly.
- They are wrinkle resistant and quite lightweight.
- They are less expensive and readily available.
- The clothes made from synthetic fibres are easier to maintain.
Ans.2.
- A plastic which once set does not become soft on the heating again and cannot be moulded second time is called a thermosetting plastic.
- Bakelite and melamine are examples of thermosetting plastics.
Ans.3.
Polyester does not absorb sweat which will make anyone uncomfortable hence it is not suitable for summer
Answered by Ramandeep | 27 May, 2019, 11:17: AM
Application Videos
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Synthetic fibres
This video explains about Synthetic fibres -
Uses of Nylon
The video discusses the Characteritics and uses of Nylon.
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