Man-Made Materials — Set 2
Chemistry · मानव निर्मित सामग्री · Questions 11–20 of 50
Which synthetic rubber is commonly used for making wetsuits and gaskets?
Correct Answer: B. Neoprene
Neoprene exhibits excellent chemical stability and maintains flexibility over a wide temperature range. It is resistant to degradation from the sun, ozone, and weather. This makes it a preferred material for marine and industrial applications.
Which plastic is commonly used to make lightweight, transparent bottles for carbonated drinks?
Correct Answer: D. PET
PET stands for Polyethylene Terephthalate, which is a strong and lightweight form of polyester. It provides a good barrier against gas and moisture, keeping drinks fresh. It is also the most widely recycled plastic in the world.
Which substance is used as a 'Plasticizer' to make hard plastics like PVC more flexible?
Correct Answer: D. Phthalates
Phthalates are added to polymers to increase the space between chains, allowing them to slide past each other. This reduces the brittleness of the material and makes it pliable for products like garden hoses. Their use is carefully regulated due to health and environmental concerns.
The main component of optical fibers used in telecommunications is?
Correct Answer: B. Ultra-pure Silica
Ultra-pure silica allows light signals to travel long distances with minimal loss of intensity. The fiber uses the principle of total internal reflection to transmit data. It is much more efficient and lighter than traditional metal wires.
Which synthetic polymer is used to make disposable cups and packaging foam?
Correct Answer: D. Polystyrene
Polystyrene, often known by the brand name Styrofoam, is an excellent thermal insulator. It is lightweight because it contains a large amount of air trapped within its structure. However, it is difficult to recycle and persists in the environment.
Terylene is a popular synthetic fiber belonging to which class of polymers?
Correct Answer: C. Polyesters
The correct answer is 'Polyesters'. Terylene is produced by the condensation polymerization of ethylene glycol and terephthalic acid. It is crease-resistant and used extensively in the textile industry for clothing. When mixed with cotton, it is known as Terrycot.
Which material is used for making lenses of spectacles and camera filters?
Correct Answer: D. Flint glass
Flint glass has a high refractive index and high dispersion, making it ideal for optical instruments. It typically contains lead or other heavy elements to enhance its clarity. It is often used in combination with crown glass to make achromatic lenses.
Which polymer is used as a substitute for glass in making bulletproof windows and aircraft canopies?
Correct Answer: D. Polycarbonate
Polycarbonate is a tough, transparent plastic with very high impact resistance. It is much lighter than glass and can withstand significant forces without shattering. It is also marketed under trade names like Lexan or Makrolon.
What is the primary ingredient of 'Safety Glass' used in car windshields?
Correct Answer: B. Laminated plastic layer
Safety glass consists of a layer of plastic, usually polyvinyl butyral, sandwiched between two layers of glass. This lamination prevents the glass from shattering into sharp pieces during an accident. The shards remain stuck to the plastic layer, reducing the risk of injury.
Which synthetic material is used for making artificial turf (grass) in sports stadiums?
Correct Answer: A. Nylon or Polypropylene
Nylon and polypropylene are chosen for their durability and resistance to wear and tear. These polymers can be colored green and shaped like grass blades to provide a consistent playing surface. Artificial turf requires less maintenance and water than natural grass.