Question

A. Answer in Detail (Summative Assessment)

1. With the help of an experiment, how will you prove that plastics are bad conductors of heat

2. Explain what are thermoplastics and thermosetting plastics. Give two examples of each.

3. Write a note on the uses of synthetic fibres.

4. Explain the general properties of plastics.

5. Give reasons for each of the following:
(a) Electrical wires have plastic coating.

(b) Cooking pans have handles made of plastics.

(c) Clothes made of synthetic fibres are not very comfortable to wear.

(d) Plastic articles are more popular than the ones made of metals.​

Answer 1

Answer:

a) Take a burner a plastic spoon and a metal spoon put the the spoon over the burner one by one you will see that in metals phone after sometime your finger you will feel the heat but in plastic spoon you will not feel the heat this proves that plastics are bad conductor of heat

b) a plastic a plastic which onceset does not become soft and heating and cannot be more second time is called thermosetting plastic some of the example of thermosetting plastics are bakelite and melamine

A plastic which can be softened

repeatedly by heating and can be mould into different shapes again and again is called thermoplastic some of the example of thermosetting plastic are polythene and polyvinyl chloride ( PVC)

3.) The man-made fibre produced from chemical substances are called synthetic fibre.it is made in industry using the chemical process called polymerisation there are four type of synthetic fibre rayon nylon polyester acrylic