Q1. Polyethylene and polyvinyl chloride resins are used in various parts of building areas for:
  • structural strength
  • structural ductility
  • water proofing
  • termite proofing

Correct Answer: C. water proofing

Solution:

Polyethylene (PE) and Polyvinyl Chloride (PVC) are plastics known for their excellent resistance to moisture. They are non-porous and are widely used to manufacture pipes, sheets, and membranes for waterproofing applications in construction.

Q2. Which of the following is NOT true about PVC pipes?
  • They have good insulation properties hence the temperature of water passing through such pipes is not effected by outside temperature.
  • They possess high Hazen Williams Constant and it results into adaptation of smaller size of PVC pipes compared to other conventional materials.
  • They have no problem of incrustation.
  • They possess low coefficient of expansion as compared to cast-iron or galvanized-iron pipes.

Correct Answer: D. They possess low coefficient of expansion as compared to cast-iron or galvanized-iron pipes.

Solution:

This statement is false. Plastics, including PVC, have a significantly higher coefficient of thermal expansion than metals like cast iron or steel. This means they expand and contract much more with temperature changes, which must be accounted for during installation.

Q3. Plastic asphalt is:
  • Used as water proofing layer over roof
  • A mixture of cement and asphalt
  • A natural asphalt
  • A refinery product

Correct Answer: B. A mixture of cement and asphalt

Solution:

Plastic asphalt, often used for roofing and waterproofing, is a composite material made by mixing asphalt with fillers. While various fillers can be used, it is commonly a mixture of cement (or other minerals) and asphalt, which gives it a thicker, more plastic consistency.

Q4. Which of the following is not an example of thermoplastic?
  • polyethylene
  • nylon
  • PVC
  • Bakelite

Correct Answer: D. Bakelite

Solution:

Thermoplastics (like polyethylene, nylon, and PVC) can be repeatedly softened by heating and hardened by cooling. Bakelite, however, is a thermosetting plastic. Once it is cured and hardened, it cannot be remelted or reshaped.

Q5. Original plastic material without fiber reinforcement is called:
  • Composite
  • Admixture
  • Binding agent
  • Virgin Plastic

Correct Answer: D. Virgin Plastic

Solution:

Virgin plastic is the term for direct-from-petrochemical-source plastic resin that has not been recycled or mixed with other materials like reinforcements. A composite is a material made from two or more constituent materials with significantly different properties.

Q6. Pick up the non-inflammable plastic from the following:
  • Cellulose acetate plastics
  • Polyvinyl chloride plastics
  • Phenol formaldehyde plastics
  • Urea formaldehyde plastic

Correct Answer: B. Polyvinyl chloride plastics

Solution:

Polyvinyl chloride (PVC) is inherently flame retardant due to its chlorine content. It is difficult to ignite and tends to self-extinguish when the flame source is removed, making it effectively non-inflammable compared to many other common plastics.

Q7. Plastics are examples of:
  • anhydrides
  • polymeric materials
  • ceramic materials
  • elastomers

Correct Answer: B. polymeric materials

Solution:

Plastics are a major class of synthetic or semi-synthetic materials that are made up of polymers. A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Therefore, plastics are prime examples of polymeric materials.

Q8. Following is not the process involved in the fabrication of articles of plastic:
  • Laminating
  • Blowing
  • Calendaring
  • Tempering

Correct Answer: D. Tempering

Solution:

Laminating, blowing (blow molding), and calendaring are all common industrial processes for shaping and fabricating plastic articles. Tempering is a heat treatment process used to increase the toughness of metals and glass; it is not used for plastics.