1. Natural sands are economical than synthetic sands?
a) True
b) False
Explanation: In natural sands, the amount of availability of it is quite abundant, also, there need not be much of further operations on the natural sands unlike synthetic sands. Natural sands involve a much lesser cost as compared to synthetic sands, as lesser control is needed there.
2. What is the amount of clay content in Loam sand?
a) 30%
b) 40%
c) 50%
d) 60%
Explanation: Clay content in loam sand is relatively more than that of in natural sand. Also, the amount of humid content or the levels of water too in loam sand would be differing similarly. The clay content in loam sand is around 50%.
3. Which sand is used for making ferrous and non-ferrous alloys?
a) Natural sand
b) Synthetic sand
c) Loam sand
d) Refractory sand grain
Explanation: Natural sands are used for casting ferrous and non-ferrous metals while synthetic sands are used for casting ferrous and non-ferrous alloys.
4. A general loam sand mixture contains how many volumes of silica?
a) 10
b) 20
c) 30
d) 40
Explanation: In general loam sand, the moisture is found to contain a decently good amount of clay content in it. A general loam sand mixture contains 20 volumes of silica, the moisture of 20% and manure 1 volume.
5. Round grain has higher permeability than angular grains.
a) True
b) False
Explanation: Round grains do not have a better bond and possess lesser strength. Round grain has higher permeability than angular strength.
6. Which of the following is not a characteristic property of any moulding sand?
a) Flowability
b) Hardenability
c) Green strength
d) Dry strength
Explanation: Flowability, green strength and dry strength are few of the characteristic properties of moulding sand, but not hardenability.
7. What does a mould having adequate green strength, does not have?
a) Ability to retain its shape
b) Ability not to get distorted
c) Ability not to collapse
d) Ability to retain hardness
Explanation: For a mould to be having an adequate amount of green strength, it must have retaining ability or the ability to get distorted or to collapse. A mould having adequate green strength does not have the ability to retain hardness.
8. Dry sand does not have the strength for what functions?
a) To withstand corrosion forces
b) To withstand pressure of molten metal
c) To be able to retain its shape
d) To be able to retain the hardenability
Explanation: Dry sand has its strength for various purposes like, to withstand a pressure of molten metal, to withstand corrosion forces and to be able to retain its shape. But it does not have it for being able to retain the hardenability.
9. Hot strength is seen at what temperature?
a) Above 212°F
b) Above 312°F
c) Above 412°F
d) Above 512°F
Explanation: Hot strength basically is the strength of the sand which is present inside the mould cavity. It is observed that, the hot strength of any material is at 212°F or above it.
10. Which of the following would not happen if hot strength is not enough?
a) The mould may get hardened
b) The mould may get enlarged
c) The mould may get eroded
d) The mould may crack
Explanation: If there is not an adequate amount of hot strength provided, then the mould may get enlarged, the mould may get eroded and the mould may crack, but the mould will not get hardened.