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This section includes 14 Mcqs, each offering curated multiple-choice questions to sharpen your Materials Science knowledge and support exam preparation. Choose a topic below to get started.
1. |
A 34.6% Pb-Sn alloy is cooled just below the eutectic temperature (183°C). What is the fraction of proeutectic α and eutectic mixture (α+β)? |
A. | 70% and 30% |
B. | 64% and 36% |
C. | 36% and 64% |
D. | 30% and 70% |
Answer» C. 36% and 64% | |
2. |
Any composition left of point c or right of point d will cool and solidify like a _______ |
A. | Eutectic |
B. | Proeutectic |
C. | Eutectoid |
D. | Isomorphous system |
Answer» E. | |
3. |
At the eutectic point (e) the eutectic reaction proceeds at a constant temperature as ________ |
A. | F = 1 |
B. | F = 0 |
C. | F = 2 |
D. | F = 3 |
E. | the eutectic reaction proceeds at a constant temperature as ________a) F = 1b) F = 0c) F = 2d) F = 3 |
Answer» C. F = 2 | |
4. |
The inflection in the cooling curve between points a and e is due to _________ |
A. | Latent heat |
B. | Low temperature |
C. | High temperature |
D. | Specific heat |
Answer» B. Low temperature | |
5. |
At point b, the α (alpha) fraction is given by the lever rule as ________ |
A. | fraction is given by the lever rule as ________a) mn/bn |
B. | bn/mn |
C. | ab/be |
D. | be/ab |
Answer» C. ab/be | |
6. |
Crystals of which material begin to form at point a from the figure? |
A. | Crystals of proeutectic α |
B. | Crystals of proeutectic β |
C. | Crystals of eutectic (α+β) |
D. | Crystals of proeutectic α and β |
Answer» B. Crystals of proeutectic β | |
7. |
The micro structure of hypoeutectic alloys at room temperature consists of ________ |
A. | Proeutectic β and α |
B. | Eutectic mixture (α+β) |
C. | Proeutectic β and eutectic mixture (α+β) |
D. | Proeutectic α and eutectic mixture (α+β) |
Answer» E. | |
8. |
What is the point at which three phases (L+α+β) coexist at point E? |
A. | Peritectic point |
B. | Eutectic point |
C. | Eutectoid point |
D. | Peritectoid reaction |
Answer» D. Peritectoid reaction | |
9. |
What is the line that defines the solubility limit of A in B and B in A from the figure? |
A. | Solidus line |
B. | Liquidus line |
C. | Solvus line |
D. | Solidus line and Liquidus line |
Answer» D. Solidus line and Liquidus line | |
10. |
The_inflection_in_the_cooling_curve_between_points_a_and_e_is_due_to__________$ |
A. | Latent heat |
B. | Low temperature |
C. | High temperature |
D. | Specific heat |
Answer» C. High temperature | |
11. |
At any point b, the αfraction is given by the lever rule as _______?# |
A. | mn/bn |
B. | bn/mn |
C. | ab/be |
D. | be/ab |
Answer» C. ab/be | |
12. |
Why Pb-Sn eutectic alloys are used for soldering purpose? |
A. | The melting point at eutectic point is maximum |
B. | The melting point at the eutectic point is minimum |
C. | The melting point at the eutectic point is constant |
D. | The boiling point at the eutectic point is maximum |
Answer» B. The melting point at the eutectic point is minimum | |
13. |
In hypoeutectic alloys micro structure at room temperature consists of________ |
A. | Proeutectic β and α |
B. | Eutectic mixture (α+β) |
C. | Proeutectic β and eutectic mixture (α+β) |
D. | Proeutectic α and eutectic mixture (α+β) |
Answer» C. Proeutectic ‚âà√≠‚Äö√¢¬ß and eutectic mixture (‚âà√≠¬¨¬±+‚âà√≠‚Äö√¢¬ß) | |
14. |
Three phases (L+α+β) coexist at point E. This point is called _____$ |
A. | Peritectic point |
B. | Eutectic point |
C. | Eutectoid point |
D. | Eutectic point or composition |
Answer» E. | |