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1. Glass evidence is considered :
- Individual evidence
- Class evidence
- Sometimes individual, sometimes class depending on the circumstances
- Not very good evidence because it’s everywhere
Answer
Answer: (3) Sometimes individual, sometimes class depending on the circumstances
2. ____________ is a supercooled amorphous solid-liquid which has attained so high viscosity as to be considered as solid.
- Plastics
- Glass
- Acrylic fiber
- Both (1) and (2)
Answer and Explanation
Answer: (2) Glass
Explanation: Factfully, Glass is actually neither a supercooled liquid nor a solid. It is an amorphous solid whose properties are somewhere between supercooled liquid and solid matter.
3. Anisotropic materials have
- Single refractive index
- Two or three principle refractive indices
- No refractive index
- None of the above
Answer and Explanation
Answer: (2) Two or three principle refractive indices
Explanation:
-> Isotropic Materials: For every wavelength, it will only have a single and constant refractive index.
-> Anisotropic materials: have two or three principle refractive indices for a particular wavelength. This is due to its asymmetric internal structure that causes variation in characteristics and behaviors with the direction of applied light.
-> They are divided into two types:
(1) Uniaxial Anisotropes: have crystalline terta and hexagonal system. For each wavelength, they have two extreme refractive indices.
(2) Biaxial Anisotropes: have mono, ortho, and triclinic crystal system. They have three refractive indices: two opposite extremes, and one being neutral between two.
Reference: Properties of Light and Examination of Isotropic Substances
4. Which of the following is the most prevalent form of glass?
- Borosilicate glass
- Soda Lime glass
- Tempered glass
- Laminated glass
Answer
Answer: (2) Soda Lime glass
5. The approximate weight percent of SiO2 in borosilicate glass is:
- 40%
- 50%
- 60%
- 80%
Answer
Answer: (4) 80%
6. Following are the components of soda lime glass, except:
- Calcium hydroxide
- Silicon dioxide
- Sodium oxide
- Calcium oxide
Answer
Answer: (1) Calcium hydroxide
7. The most abundant compound in soda lime glass is:
- Silicon dioxide
- Sodium oxide
- Calcium oxide
- Both (2) and (3)
Answer and Explanation
Answer: (1) Silicon dioxide
Explanation: General composition of soda lime glass in wt%:
-> Silicon dioxide (silica): 70-75%
-> Sodium oxide (soda): 12-16%
-> Calcium oxide (limestone): 10-15%
-> Other oxides: Rest%
Reference: Glasses and ceramics [ScienceDirect]
8. In borosilicate glass, silica is at higher percentage, and second most shares by:
- Lead oxide
- Aluminum oxide
- Boron trioxide
- Magnesium oxide
Answer and Explanation
Answer: (3) Boron trioxide
Explanation: Composition of Borosilicate glass (also called heat resistant glass)::
-> Silica (SiO2): 70% to 80%
-> Boron trioxide (boric oxide, B2O3): 7-13%
-> Sodium/potassium Oxide: 4-8%
-> Aluminum Oxide (Al2O3): 2-8%
Reference: Borosilicate Glass – an overview | ScienceDirect
9. Low borate borosilicate glass contains boron trioxide in range of:
- 2 to 3%
- 4 to 8%
- 7 to 13%
- 12 to 15%
Answer and Explanation
Answer: (3) 7 to 13%
Explanation: Low-borate borosilicate glass majorly shares 7 to 13% of boron trioxide.
-> Used mainly for producing chemical apparatus and lamps.
10. High borate borosilicate glass contains boron trioxide in range of:
- 15% to 27%
- 18% to 27%
- 20% to 27%
- 25% to 30%
Answer and Explanation
Answer: (3) 15 to 27%
Explanation: High borate borosilicates are sometimes called leachable alkali-borosilicate glasses. Optimum composition is (by wt%):
-> Silica: 62.7%
-> Boron trioxide: 26.9%
-> Sodium oxide: 6.6%
-> Aluminum oxide: 3.5%
11. Controlled Pore Glasses are widely used in
- Chromatography
- IR spectroscopy
- NMR
- Atomic Absorption spectra quartz
Answer and Explanation
Answer: (1) Chromatography
Explanation:
-> Can be used as a separation media for TLC and paper and chromatography.
-> Borates and silicates are removed from the borosilicate base, leaving behind silica glass with uniform, controlled pores.
12. In soda-lime glass, the main purpose of adding calcium oxide is:
- To increase the thermal expansion
- To decrease the the alkali fumes
- To make the glass surface crossed linked for white glass formation
- To improve the insolubility of sodium ions
Answer and Explanation
Answer: (4) To improve the insolubility of sodium ions
Explanation: Sodium ions in soda-lime glass are soluble in an aqueous solution, to make them insoluble, calcium oxide (CaO) is added to the mixture.
13. For the recycling process, glass is crushed into a sand-like substance called
- Dices
- Cartein
- Cullet
- Both (2) and (3)
Answer and Explanation
Answer: (3) Cullet
Explanation: Glasses are broken down into a sand-like substance called cullets.
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