Materials Science Multiple Choice Questions & Answers (MCQs) on “Unary Phase Diagrams”.
1. Which of the following are examples of unary phase diagrams?
a) Cu-Ni phase diagram
b) Water phase diagram
c) Cu-Pd phase diagram
d) Mg-Db phase diagram
Answer:b
Clarification: The simplest phase diagram is the water which is a one component system.
2. What are the external parameters that affect the phase structure?
a) Temperature, Pressure
b) Temperature, Composition
c) Pressure, Composition
d) Temperature, Pressure, Composition
Answer: d
Clarification: The phase of the system changes accordingly with an increase or decrease in the above parameters.
3. What is the phase fraction of an alloy when it is one phase system?
a) 0.6
b) 0.8
c) 0.5
d) 1.0
Answer: d
Clarification: Urinary phase diagram is a phase diagram of a single component over a range of temperature-pressure. It may consist of one or more phases but its chemical composition remains the same.
4. What will be the phase composition of a phase system?
a) The composition of each phase is same throughout the phase diagram
b) The composition of each phase is different throughout the phase diagram
c) Contains more than one composition in the entire phase diagram
d) Varies from molecule to molecule
Answer: a
Clarification: The composition of each phase is the same throughout the phase diagram.
5. Which of the following remains constant in Unary phase diagrams?
a) Pressure
b) Temperature
c) Composition
d) Both pressure and temperature
Answer: c
Clarification: Since there is only one phase there will be only one substance.
6. Along the phase boundaries, the phases on either side will be in ______
a) Equal
b) Equilibrium
c) Different
d) Constant
Answer: b
Clarification: At phase boundary, the phase compositions will be the same.
7. What is a triple point?
a) All three states are in equilibrium
b) All three states are not in equilibrium
c) All three states don’t exist
d) All three states don’t exist and are not in equilibrium
Answer: a
Clarification: In triple point, all the states exist and are in equilibrium.
8. What is the temperature at triple point of water?
a) 288 K
b) 273.16 K
c) 298 K
d) 277 K
Answer: b
Clarification: At 273.16 k all the three phases of water will be in equilibrium.
9. What is pressure at a triple point of water?
a) 5.08×10-3 atm
b) 6.04×10-3 atm
c) 7.04×10-3 atm
d) 6.44×10-3 atm
Answer: b
Clarification: At 6.04×10-3 atm all the three phases of water will be in equilibrium.
10. Which of the following is unary phase diagram?
a)
b)
c)
d)
Answer: a
Clarification: Unary phase diagram consists of only one substance.