Test: Synthetic Fibres And Plastics (Medium)

20 Questions MCQ Test Science Class 8 | Test: Synthetic Fibres And Plastics (Medium)

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Like synthetic fibres, plastic is also a:

Solution: Synthetic fibres are made up of raw materials such as petroleum, based on chemicals and petrochemicals, which are polymerized into a long, linear chemical with different chemical compounds.

Plastics are organic polymers of high molecular mass and contain other substances, called monomers. Therefore, we can say that both synthetic fibres and plastics are made by polymerization of their monomer units.


The use of plastic material polyesters is in:

Solution: Plastic material polyester used in Recording tapes.


Which type of cloth dries faster in the rainy season?

Solution: Synthetic fibres like polyesters dry up quickly.


Rayon blended in wool will result in

Solution: Rayon is a synthetic fibre that is breathable and drapes well. A rayon/cotton blend is common. Rayon lends a silky feel and appearance to the blend but like cotton, it's prone to creases. Still, rayon wrinkles less than cotton which adds benefit to the fabric blend.


Define Plasticity:

Solution: Plasticity, the ability of certain solids to flow or to change shape permanently when subjected to stresses of intermediate magnitude between those producing temporary deformation, or elastic behavior, and those causing failure of the material, or rupture.


Which of the following statements is true about thermosetting plastic?

Solution: Thermosetting plastics contain polymers that cross-link together during the curing process to form an irreversible chemical bond. It can't be recycled. The cross-linking process eliminates the risk of the product remelting when the heat is applied, making thermosetting ideal for high-heat applications such as electronics and appliances.


Animal fibres are made of:

Solution: Protein, animal fibers are natural fibers that consist largely of particular proteins. Instances are silk, hair/fur (including wool) and feathers. The animal fibres used most commonly both in the manufacturing world as well as by the hand spinners are wool from domestic sheep and silk.


Which of the following items cannot be recycled?

Solution: Plastic containers are relatively dense and compact which enables them to be easily sorted mechanically, into the different types of plastics. Plastic film and bags are not easily mechanically sorted making them very costly to sort. Also, recycling such plastic is an expensive process.


Electrical wires have a coating of insulating material. The material generally used for insulation is:


PVC is an insulator and prevents electricity to be conducted outside the wire so that electric shock can be prevented.


Containers that are lightweight, lower price, good strength, and easy to handle is made up of:

Solution: Plastic has lightweight, lower price, good strength, and easy to handle. Therefore, the container is made from plastic.


Which of the following statements is incorrect?

Solution: Nylon: A synthetic material, nylon isn't anything but a cool fabric to weather in the summer as it's specifically designed to repel water.


The general formula of alkynes is ...............

Solution: The general formula for alkynes is CnH2n-2. Acetylene is the simplest alkyne with the formula as C2H2.


Rayon or artificial silk is obtained from:

Solution: Although rayon is obtained from a natural source of wood pulp, yet it is a man-made fiber.


We come to a conclusion, that plastics are bad conductors of electricity from the followings:

Solution: Plastic does not allow electricity to pass through it thus is called bad conductors of electricity and can be used as insulators.


Nylon is obtained by:

Solution: Nylon was first commercially synthesized fibre. The production of nylon was started almost simultaneously in New York and London, thus it got its name (NY for New York and Lon for London) as nylon. Nylon is synthesized from coal, water and air. Fibre of nylon is very strong and it also resembles silk.


Name the fibres which are made by human beings.

Solution: Synthetic fibres are made by human beings. Example – Rayon, nylon, etc.


When a small unit combines to form a large single unit then it is called __________.

Solution: A synthetic fibre is also a chain of small units joined together. Each small unit is actually a chemical substance. Many such small units combine to form a large single unit called a polymer. Example: Nylon, polythene, Teflon, etc.


Synthetic fibres are also known as ____________.


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


Name the fibre, having properties similar to that of silk.

Solution: Rayon has properties similar to silk and is therefore called artificial or synthetic fibre.


___________ is used for making parachutes and ropes for rock climbing.

Solution: Nylon fibre is used in making ropes for rock climbing and parachutes because it is a very strong fibre.