1. Which of the following is not a limitation of wooden patterns?
a) Get abraded easily
b) Absorb moisture
c) Difficult machining
d) Poor wear resistance
Explanation: Wooden patterns are the easiest to get machined than all the other materials which are used for making patterns, and hence is counted as one of its advantage and not limitation.
2. Metal patterns have a longer life than wooden pattern.
a) True
b) False
Explanation: It is true that, metal patterns have a longer life than wooden patterns, as metal patterns are stronger and accurate as compared to wooden patterns.
3. Which of the following is not a limitation of metal patterns?
a) Get rusted
b) Obtain rough surface finish
c) Expensive
d) Heavy
Explanation: In metal patterns, it is extremely easy to obtain a smooth surface finish. To achieve a smooth surface finish, it is counted as an advantage in metal patterns over wooden patterns.
4. Which of the following patterns do not withstand rough handling?
a) Aluminium
b) Cast iron
c) Brass
d) Steel
Explanation: It is one of the limitation of aluminium pattern that, it cannot withstand rough handling, while all other metal and alloy patterns can withstand it. Aluminium is the lightest metal known.
5. Which of the following has the lowest melting point?
a) Cast Iron
b) Steel
c) White Metal
d) Brass
Explanation: Among the given metals and metal alloys, white metal (tin base alloy) has the lowest melting point which is approximately 260 degrees Celsius.
6. Which of the following is the heaviest?
a) White
b) Brass
c) Cast Iron
d) Aluminium
Explanation: Aluminium and White metal are considered to be one of the lightest metals and alloys, whereas brass and cast irons are considered to be heavy materials. But, even among the two, brass is heavier than cast iron.
7. In Solid casting method, the resin mixture is kept for how much time for hardening and curing?
a) 1-2 hours
b) 2-3 hours
c) 3-4 hours
d) 4-5 hours
Explanation: A mould of Plaster of Paris is made, into which the resin mixture is poured, in solid casting. This mixture takes up 2-3 hours to harden and get cured.
8. Core boxes are made out of which pattern?
a) Plaster pattern
b) Wax pattern
c) Metal patterns
d) Polystyrene patterns
Explanation: A pattern is basically a duplicate of the object that has to be casted. It is one of the applications of plaster pattern to make core boxes and other small and intricate patterns.
9. What should the sulphur level in foam plastic be?
a) More than 1%
b) Between 0.5% to 1%
c) Less than 0.1%
d) Between 0.1% to 0.5%
Explanation: In foam plastic, for making pattern, the sulphur level must be below 0.1%. If the levels are higher than mentioned, it can be deleterious in manufacturing.
10. Which of the following patterns has high compressive strength?
a) Plastic pattern
b) Wax pattern
c) Polystyrene pattern
d) Plaster pattern
Explanation: Among plastic patterns, wax patterns and polystyrene pattern, it is plaster pattern which has the highest compressive strength. The calculated compressive strength is as high as up to 285kg/cm2.