1. Flat iron bars are used generally for:
a) R.C.C
b) Grill work
c) Roofing
d) Truss
Explanation: These are available in varying widths ranging from 10mm-400mm and thickness from 3mm-40mm. These are widely used in the construction of steel grill work for windows and gates.
2. Which of the below is not a disadvantage of using ribbed-torsteel bars?
a) High labour charge
b) Not easily identifiable
c) Weaker than plain round steel
d) Arc welding is not possible
Explanation: These bars are produced from ribbed-torsteel which is a deformed high strength steel. These bars have projections (ribs) on their surface. The bending, fixing and handling of these bars are simplified and it results in less labour charge.
3.Steel plates are rarely used for:
a) Connecting steel beams for extension
b) Serving as tension members in the truss
c) Forming built up sections of steel
d) Providing support in R.C.C structures
Explanation: Steel bars and rods are used widely in R.C.C structures. Steel plates find application in structural steel works.
4. Aluminium is commercially produced from:
a) Aluminium sulphate
b) Alum
c) Cryolite
d) Bauxite
Explanation: Bauxite is the most commonly used ore of aluminium for production. It occurs as a weathering product of iron and silica
5. By which of the below process is Aluminium manufactured?
a) Bayer process
b) Ostwald process
c) Mayer process
d) Haber process
Explanation: In the Bayer process, alumina in bauxite is dissolved in caustic soda solution and precipitated to obtain aluminium hydroxide and calcinated to form pure Al2O3.
6. Which is the most important and useful alloy of Aluminium?
a) Magnalium
b) Silumin
c) Duralumin
d) Magnox
Explanation: Duralumin consists of 95% aluminium, 4% copper, 0.5% magnesium and 0.5% manganese. It is widely used in aircraft manufacturing due to its light weight and high strength.
7. Aluminium has a higher maintenance cost.
a) True
b) False
Explanation: Aluminium has excellent corrosion resistance and can withstand weathering, hot and humid conditions also. Hence, maintenance cost required is less.
8. Which of the following is a property of aluminium?
a) Hard material
b) Brittle
c) Noise control
d) Magnetic
Explanation: Aluminium is an excellent reflector of electromagnetic and sound waves. Therefore, it is less affected by external noise compared to other building materials.
9. Aluminium appears greyish in colour in pure form.
a) True
b) False
Explanation: Pure form of Aluminium is white in colour. Its colour can vary from grey to yellow or light green depending on the presence of impurities. Yellow colour is imparted by Iron trichloride (impurity).
10. Aluminium finds its application in:
a) Golf clubs
b) Dehydrating agents
c) Waste management
d) Cricket field
Explanation: Compared to steel, aluminium is lightweight. Aluminium golf heads, shafts allow golfers to swing faster and increase the ball’s distance with each shot.