Tag: man made materials

Questions Related to man made materials

Why is plastic used in covering of electrical appliances?

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  1. Good conductors of heat and electricity

  2. Durable

  3. Poor conductors of heat and electricity

  4. None of above

Show answer
Correct Option: C
Explanation:

Plastic is a poor conductor of heat and electricity. 


This makes it suitable to make the covering of electric wires, handles of electrical appliances, handles of utensils, kitchenware, floor tiles, etc.

Hence the correct option is C.

Plastic can be used as :

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  1. insulator

  2. conductor

  3. Both A and B

  4. None of above

Show answer
Correct Option: A
Explanation:

Most plastics are both thermal and electrical insulators, meaning they show high resistance to electrical current and are poor conductors of heat.

Thermosetting polymer such as bakelite are used as electrical insulators.

Handles of most pans are made up of:

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  1. thermoplastic

  2. thermosetting plastic

  3. acrylic

  4. hemp

Show answer
Correct Option: B
Explanation:

Handles of most pans are made up of thermosetting plastic. Thermosetting plastic does not melt easily. These plastic cannot be reshaped again and again.

The world's first fully synthetic plastic was:

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  1. Polystyrene

  2. Nylon

  3. Bakelite

  4. Teflon

Show answer
Correct Option: C
Explanation:

The world's first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term 'plastics'. Bakelite is made from carbolic acid (phenol) and formaldehyde and is referred to as a phenolic resin. Bakelite was the first thermosetting plastic.


Hence, the correct option is $C$

Which of the following are the advantages of plastic over metals?
1. Plastics are lighter.
2. Plastics are usually cheaper.
3. Plastics are inert to both acids and alkalis.

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  1. (1) and (2) only

  2. (1) and (3) only

  3. (2) and (3) only

  4. (1) ,(2) and (3)

Show answer
Correct Option: D
Explanation:
With the increased knowledge of plastics and the improved capabilities of machining equipment, the industry is now capable of producing plastic components to the same exacting standards as metallic components.
Plastics can  provide the benefit of reduced weight. This is crucial for a manufacturer of aircraft parts, for instance, decreased weight means increased fuel efficiency. This has lead to manufacturers transitioning from aluminum and steel to plastic and composites.
Plastic are less sensitive to weather than metal, resisting corrosion and rust. In addition, additives can be introduced to protect the pieces from damaging UV rays.
Plastics are resistance to many more chemical compounds like acids and alkalis. This opens up the options for use in solution tanks.
Plastics can be designed for resist impact and dents, making it durable, strong, and stable.
Plastics have tighter tolerances.

Nylon is obtained by:

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  1. treating wood pulp

  2. solidifying water

  3. mixing coal, air and water

  4. mixing chemicals

Show answer
Correct Option: C
Explanation:

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.

Bakelite is an example of ___.

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  1. elastomer

  2. fibre

  3. thermoplastic

  4. thermosetting polymer

Show answer
Correct Option: D
Explanation:

A thermosetting plastic, also known as a thermoset, is a polymer material that irreversibly cures. The cure may be induced by heat, generally above $200^o C$ $(392\ F)$, through a chemical reaction or a suitable irradiation.
$Bakelite$ is one example of this type.

State True or False :

Most of the plastics are biodegradable.

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  1. True

  2. False

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Correct Option: B
Explanation:

Most of the plastics are non-biodegradable.


Hence the given statement is false.

Polystyrene and PVC are thermoplastics.

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  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Polymer of styrene and vinyl chloride (polystyrene and PVC)  can be repeatedly melted and re-molded into new products and are 100% recyclable. 


Therefore they are examples of thermoplastic. Other examples of thermoplastics include polythene (PE), polypropylene (PP), nylons, etc.

Therefore, option A is correct.

Which of the following will be suitable for coating dress materials of fire - men ?

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  1. Nylon

  2. Polyster

  3. Melamine

  4. Acrylic

Show answer
Correct Option: C
Explanation:

Melamine have properties to interfere with the combustion in many different ways. Moreover, it can withstand high temperature, it is corrosion resistant and easy to handle.