1. Which of the following is not a defect if permeability is not enough?
a) Brittleness
b) Gas holes
c) Mould blast
d) Surface blows
Explanation: If the permeability or the porosity is less or the permeability is found to be inadequate or the porosity is found to be absent, then brittleness is not the defect it has, but it may have, gas holes or mould blasts or surface blows.
2. In green sand what is the amount of water used?
a) 5%
b) 10%
c) 15%
d) 20%
Explanation: In green sand, the amount of clay that is needed in percentage composition is around 15% to 30%. The amount of water in terms of percentage composition is about 5%.
3. What is the amount of clay needed in green sand?
a) 5% – 10%
b) 5% – 15%
c) 15% – 30%
d) 25% – 40%
Explanation: In green sand, the amount of clay needed in terms of percentage composition is approximately in between 15% to 30% and the amount of water needed in terms of percentage composition is somewhere around 5%.
4. Which of the following is not refractory sand?
a) Olivine
b) Silica Sand
c) Dolomite
d) Barium Chloride
Explanation: Among the following, Barium Chloride is not refractory sand, as it is counted under foundry fluxes, whereas all remaining sands are refractory sands.
5. Which refractory sand has the best moulding material?
a) Silica sand
b) Magnesite
c) Zircon
d) Olivine
Explanation: Silica sands are considered to be having the best moulding material. It has its occurrence in a variety of crystalline modifications.
6. Ganister is another name for which sand?
a) Magnesite
b) Zircon
c) Silica sand
d) Dolomite
Explanation: Ganister is another name for silica sand. As, silica is obtained from carbon-ferrous sandstone, also known as dinas.
7. At what temperature, does quartz melt completely?
a) 1725°C
b) 1925°C
c) 1825°C
d) 2025°C
Explanation: Quartz gets melted completely at 1725°C. After reaching this temperature, the quartz would then start undergoing transformations.
8. Which of the following is the most porous sand?
a) Silica sand
b) Zircon
c) Olivine
d) Dolomite
Explanation: Even when the silica sand are packed as mould cavity, they show enough porosity and permeability, and hence are porous sands.
9. At what temperature does the silica sand start expanding thermally?
a) 918°F
b) 843°F
c) 1063°F
d) 1124°F
Explanation: It is one of the disadvantages of silica sand, that it has its thermal expansion temperature at 1063°F. At this temperature, the volume of the sand starts to increase.
10. Which of the following sand is freely available?
a) Silica sand
b) Zircon
c) Olivine
d) Dolomite
Explanation: Silica sand has this as one of its advantages, that it is available without any difficulty in abundance. Hence, the cost of silica sand is also low.