1. What is the melting point of Aluminium?
a) 250oC
b) 658oC
c) 700oC
d) 470oC
Explanation: The boiling point of aluminium is 2470oC. It is strong and can be widely used everywhere.
2. Recycled Aluminium is called:
a) Primary Aluminium
b) Green Aluminium
c) Secondary Aluminium
d) Subsequent Aluminium
Explanation: Recycled Aluminium is called secondary aluminium and same properties of primary aluminium.
3. What is a vehicle in paint used for?
a) To obscure surface
b) To adhere to surface
c) To provide shine to surface
d) To reduce crack on surface
Explanation: Paint consists of two ingredients-a base and a vehicle. Base helps to obscure the surface. A vehicle allows even spreading, binding and adhering to surface.
4. Paint should provide resistance to:
a) Corrosion
b) Sound
c) Heat
d) Warping
Explanation: Paint should resist corrosion and protect the surface over which it is applied.
5. The base in a paint does not serve the function of:
a) Durability
b) Hard and elastic
c) Protection against UV rays
d) Catalyst
Explanation: There are certain components called driers in the paint. They act as catalysts.
6.Which of the below is the most commonly used base?
a) Red lead
b) Zinc white
c) White lead
d) Oxide of iron
Explanation: White lead possess good bulk, it is dense, permanent and water proof. It is a carbonate of lead and forms the base in lead paints.
7. Lithophone is a base widely used for exterior works.
a) True
b) False
Explanation: Lithophone changes colour when exposed to day light. Hence, it is used for interior works of inferior quality.
8. How does drier act as a catalyst?
a) Releasing oxygen
b) Releasing water
c) Absorbing oxygen
d) Absorbing water
Explanation: Drier accelerates the rate of drying of paint film. It absorbs oxygen from the atmosphere and transfers it to a vehicle, which in turn hardens.
9. Which of the below vehicles are used for ordinary work?
a) Nut oil
b) Poppy oil
c) Stand oil
d) Linseed oil
Explanation: Nut oil is colourless and it dries rapidly. It is cheap as it is prepared from ordinary walnuts. Hence, these are used for ordinary works.
10. When should drier be added to the paint?
a) 12 hours before paint is used
b) Immediately after opening it
c) 1 hour before paint is used
d) When paint is ready to use
Explanation: Driers when added to paint, will start doing their action as a catalyst immediately. This will lead to hardening of paint, decreasing workability.