Casting, Forming and Welding Multiple Choice Questions & Answers (MCQs) on ” Heating And Pouring”.
1. For casting operation, a metal must be heated to what temperature?
a) Above solidifying temperature
b) Above vapourising temperature
c) Above melting temperature
d) Above room temperature
Answer: c
Clarification: For casting operations to take place, the metal to be casted must be heated above the melting temperature. The casting cannot be done at room temperature, as the metal needs to be liquefied first.
2. Which of the following is not a furnace used for heating?
a) Cupola furnace
b) Crucible furnace
c) Electric arc furnace
d) Blow air furnace
Answer: d
Clarification: Among the following, blow air furnace is not a type of furnace which is used for the heating purposes, whereas cupola, crucible and electric arc, are furnaces which are regularly used for heating.
3. Heat required to raise the temperature to the melting point is called what?
a) Sensible heat
b) Latent heat
c) Calorific heat
d) Specific heat
Answer: a
Clarification: Heat required to raise the temperature to the melting point is called as sensible heat. When there is a change of state of a material, keeping the temperature constant, that heat is called as latent heat.
4. The heat needed for a change of state of a material without changing the temperature is called what?
a) Sensible heat
b) Latent heat
c) Calorific heat
d) Specific heat
Answer: b
Clarification: The heat needed for a change of state of a material without changing the temperature is called as latent heat. Latent heat is also referred to as hidden heat.
5. If there is an increase in the mass of the metal being heated, how would it affect the total heat energy required to raise the temperature of metal?
a) Increases
b) Decreases
c) No affect
d) Quantities not related
Answer: a
Clarification: With an increase in the mass of the metal which is being heated, there would be an increase in the total heat energy which is required to raise the temperature of the metal.
6. What is the unit of specific heat of solid metal?
a) J/kg
b) J °C/kg
c) J/kg °C
d) °C/kg
Answer: c
Clarification: The units to measure the specific heat of a solid metal or that of liquid metal is given by J °C/kg, where Joule is unit of energy, Celcius is the unit of temperature and kg is the unit of mass.
7. When the molten metal is put into the mold, what is that temperature called?
a) Melting temperature
b) Vapourising temperature
c) Pouring temperature
d) Room temperature
Answer: c
Clarification: For a molten metal to be able to be poured, the temperature which it is required to possess is called as pouring temperature. This temperature is higher than the melting temperature but lower than the melting temperature.
8. In any flow through a system, if the area of cross section in which the metal is flowing, decreases, how will it affect the velocity?
a) Increases
b) Decreases
c) No affect
d) Quantities not related
Answer: a
Clarification: If the area of cross section of the system through which the molten metal is flowing, gets a decrease, then the velocity of the flow would increase, as the two hold an inverse relation.
9. What is the shape of the sprue?
a) Cuboidal
b) Cubicle
c) Trapezoidal
d) Spherical
Answer: c
Clarification: The sprue is essentially tapered, giving it a trapezoidal look. It needs to be tapered, because of the inverse relation between area and velocity.
10. According to Bernoulli’s theorem, energies at two points in a flowing liquid are equal.
a) True
b) False
Answer: a
Clarification: According to Bernoulli’s theorem, the energies at two points in a flowing liquid, in a system having equal or unequal cross section areas, at same or different heights, are equal.