Q&A Bank

Questions & Answers

4,192 answers across all subjects

Subject:Mathematics Science English Social Studies Hindi Physics Chemistry Biology Computer Science

Indicate whether the following statements are True or False. Also write the false statements in their correct form. (i) The fabric terywool is obtained by mixing terylene and wool. (ii) Synthetic fibres do not melt on heating. (iii) It is risky to wear synthetic clothes while working in the kitchen. (iv) Most of the plastics are biodegradable.

True False- Synthetic fibres do not melt on True because synthetic clotes melts on exposure to heat False- Plastics are non-biodegradable

ScienceClass 8CBSE

1. Unscramble the jumbled words given below, related to synthetic materials. (a) anory (b) lopmery (c) relyteen (d) laspict (e) yespolter felton

Soln: rayon polymer terylene plastic polyester Teflon

ScienceClass 8CBSE

Match items in List A with the items of list B. List A List B (a) nylon (i) non-stick coating (b) PET (ii) electric switches (c) rayon (iii) parachutes (d) thermosetting plastics (iv) polyester teflon (v) artificial silk

List A List B nylon (iii) parachutes PET (iv) polyester rayon (v) artificial silk thermosetting plastics (ii) electric switches teflon (i) non-stick coating

ScienceClass 8CBSE

Fill in the blanks. (i) A polymer is a chain of many small units joined together which are called . (ii) The synthetic fibres are also known as fibres. (iii) The first fully synthetic fibre was . (iv) A fibre similar to wool is . A plastic used for making crockery is

A polymer is a chain of many small units joined together which are called The synthetic fibres are also known as man made The first fully synthetic fibre was Nylon. A fibre similar to wool is A plastic used for making crockery is melamine

ScienceClass 8CBSE

PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Can you write the major difference between these two types of plastics?

On heating Thermo plastics get deformed and they can be easily bent . Whereas Thermosetting plastics cannot be softened by heating.

ScienceClass 8CBSE

A lady went to the market to buy a blanket. The shopkeeper showed her blankets made of acrylic fibres as well as made of wool. She preferred to buy an acrylic blanket. Can you guess why?

Lady prefer acrylic blanket over wool blankets because acrylic blankets are cheap, light in weight, more durable and are available in variety of colours and designs. They can be easily washed at home

ScienceClass 8CBSE

Rohit took with him some nylon ropes, when he was going for rock climbing. Can you tell why he selected nylon ropes instead of ropes made of cotton or jute?

Because Nylon ropes are strong, flexible and elastic when compared to jute and cotton ropes. Acrylic blankets are cheap, light in weight, more durable and are available in variety of colours and designs. They can be easily washed at home.

ScienceClass 8CBSE

A bucket made of plastic does not rust like a bucket made of iron. Why?

Plastic is a non-reactive material. To form rust it should react with water and oxygen. Hence plastic donot form rust.

ScienceClass 8CBSE

Select the articles from the following list which are biodegradable. (a) paper (b) woolen clothes (c) wood (d) aluminium can (e) plastic bag peels of vegetables

Paper Woolen clothes Wood f) peels of vegetables

ScienceClass 8CBSE

Why is it not advisable to burn plastic and synthetic fabrics?

Burning of plastic releases toxic gases which pollutes air. Hence it not advisable to burn plastic and synthetic fabrics.

ScienceClass 8CBSE

Plastic is used for making a large variety of articles of daily use and these articles are very attractive. But it is advised to avoid the use of plastic as far as possible. Why?

Plastic is not bio-degradable and disposing of plastic waste is a major issue. Hence it is advised to avoid the use of plastic as far as possible.

ScienceClass 8CBSE

Plastic articles are available in all possible shapes and sizes. Can you tell why?

It is very easy to make moulds from plastic hence it is available in all possible shapes and sizes.

ScienceClass 8CBSE

Terrycot is made by mixing two types of fibres. Write the names of the fibres.

Terrycot is prepared by mixing terylene and cotton.

ScienceClass 8CBSE

A synthetic fiber which looks like silk is obtained by chemical treatment of wood pulp. It is, therefore, known as artificial silk. What is its common name?

Rayon is known as artificial silk.

ScienceClass 8CBSE

Cotton is a natural polymer. What is its chemical name?

Chemical name of cotton is cellulose.

ScienceClass 8CBSE

The material which is commonly used for making kitchen containers is (a) PVC (b) Acrylic (c) Teflon (d) PET

Answer is (d) PET Explanation: PET or Polyethylene tetra thalate is light weight and it is used in making kitchen containers.

ScienceClass 8CBSE

1. Which of the following groups contain all synthetic substances? (a) Nylon, Terylene, Wool (b) Cotton, Polycot, Rayon (c) PVC, Polythene, Bakelite Acrylic, Silk, Wool

Soln: Answer is (c) PVC, Polythene, Bakelite Explanation: In option a) and c) there is wool which is extracted from animal source. In option b) there is cotton which is from plant source. Hence the answer is (c) PVC, Polythene, Bakelite.

ScienceClass 8CBSE

Which of the following represents the correct match for items in Column A with those in Column B. Column A Column B I. Nylon (i) Thermoplastic II. PVC (ii) Thermosetting plastic III. Bakelite (iii) Fibre (a) I-(ii), II-(iii), III-(i) (b) I-(iii), II-(i), III-(ii) (c) I-(ii), II-(i), III-(iii) (d) I-(iii), II-(ii), III-(i)

Answer is (c) I-(ii), II-(i), III-(iii)

ScienceClass 8CBSE

Which of the following is not a common property of plastics? (a) Non-reactive (b) Light in weight (c) Durable Good conductor of electricity

Soln: Answer is (d) Good conductor of electricity Explanation: Plastic is a bad conductor of electricity.

ScienceClass 8CBSE

The most suitable material for the preparation of handles of cooking utensils is (a) Polythene (b) PVC (c) Nylon Bakelite

Soln: Answer is (d) Bakelite Explanation: Bakelite is a bad conductor of heat and it does not get soft on heating hence Bakelite is used to prepare handles of cooking utensils.

1 2 3 4 5 6 7 8 9 10