1. Thermoplastics have _____________
a) 1-Degree bond
b) 2-Degree bond
c) 3-Degree bond
d) 0-Degree bond
Explanation: A thermoplastic is a polymer which gets softened when heated. They have a one-dimensional network of ‘2-degree’ secondary bond. A well-known example of this kind are PET (polyethylene terephthalate), PVC (polyvinyl chloride), and PP (polypropylene) etc.
2. Which of the following is a secondary bond network of thermoplastics?
a) 1-Dimensional
b) 3-Dimensional
c) 2-Dimensional
d) 0-Dimensional
Explanation: Thermoplastics have a one-dimensional network of ‘2-degree’ secondary bond.
3. Thermoplastics become softer upon heating.
a) true
b) False
Explanation: Thermoplastics have 1-dimensional secondary bond structure, due to this, when heated, their individual polymer chains can slide one over other, thus making them softer.
4. Thermosetting plastics become softer upon heating.
a) true
b) False
Explanation: Thermosetting plastics have 2-dimensioanl primary bond structure (strong covalent cross links), thus making them stronger upon heating.
5. Which of the following are a ceramics solids?
a) Metallic, inorganic and amorphous solids
b) Non-metallic, organic and amorphous solids
c) Non-metallic, inorganic and amorphous solids
d) Non-metallic, inorganic and crystalline solids
Explanation: Ceramics are non-metallic, inorganic, amorphous solids and are mostly oxides of metals. Ceramics possess low tensile strength and are brittle
6. Which of the following is a correct refractory type of quartz?
a) Acidic
b) Basic
c) Neutral
d) Amphoteric
Explanation: Quartz is an acidic refractory and are mostly used in open-hearth furnaces, gas retorts and in glass furnaces
7. Which one of the following is not an acidic refractory?
a) Quartz
b) Sand
c) Silica brick
d) Dolomite
Explanation: Dolomite is a basic refractory.
8. Which one of the following is not a basic refractory?
a) Magnesite
b) sand
c) Dolomite
d) Alumina
Explanation: Most of the silica-based refractories, like fire clay, bricks and sand are of acidic refractories
9. Which one of the following is a neutral refractory?
a) Quartz
b) Sand
c) Silica brick
d) Silicon carbide
Explanation: Silicon carbide is a neutral refractory, whereas sand, quartz and silica brick are acidic refractories.
10. For a M10 grade RCC (Reinforced Cement Concrete), the ratio of cement to aggregate to the sand is?
a) 1:2:3
b) 1:3:4
c) 1:3:6
d) 1:2:6
Explanation: M10 grade of RCC have cement to aggregate to sand ratio equal to 1:3:6.