Physical Metallurgy MCQ Questions and Answers

41

Match the names in Group 1 with invarient reactions in binary phase diagram in Group 2.

Group 1	Group 2
P. Eutectic	1. S₁ = S₂ + S₃
Q. Eutectoid	2. L = S₁ + S₂
R. Peritectoid	3. L₁ = L₂ + S
S. Monotectic	4. S₁ + S₂ = S₃

A) P-2, Q-1, R-3, S-4 B) P-2, Q-1, R-4, S-3 C) P-3, Q-4, R-2, S-1 D) P-4, Q-3, R-1, S-2

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Answer & Solution

Answer: Option A

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42

Assume that Sievert's law holds for solubility of hydrogen dissolved in a thin metal foil. If the partial pressure of hydrogen in contact with the foil is increased by a factor of 4, the solubility increases by a factor of

A) 1 B) 2 C) 3.6 D) 4.8

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Answer & Solution

Answer: Option B

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43

Match the heat treatment processes of steel in Group 1 with the microstructural features in Group 2.

Group 1	Group 2
P. Quenching	1. Bainite
Q. Maraging	2. Martensite
R. Tempering	3. Internietallic precipitates
S. Austempering	4. Epsilon carbide

A) P-2, Q-3, R-1, S-4 B) P-1, Q-3, R-2, S-4 C) P-2, Q-3, R-2, S-1 D) P-3, Q-2, R-1, S-4

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Answer & Solution

Answer: Option C

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44

The free energy change during melting of ice at 0°C is equal to

A) Enthalpy of melting–entropy of melting B) 0 C) 273 D) Can't say without more data

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Answer & Solution

Answer: Option B

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45

At which temperature, cementite changes ferromagnetic to paramagnetic character in iron carbon diagram

A) 768°C B) 910°C C) 1147°C D) 210°C

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Answer & Solution

Answer: Option D

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46

The elastic strain energy of a unit length of an edge dislocation as compared to that of a screw dislocation is

A) More B) equal C) less D) double

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Answer & Solution

Answer: Option A

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47

The peritectic reaction in binary systems is given by

A) L = α + β B) α = L + β C) Y = α + β D) L + α = β

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Answer & Solution

Answer: Option D

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48

The critical nucleus size (in mm) when copper melt is under-cooled by 100K is
Given data:
Melting point: 1356 K
Density: 8900 kg.m^-3
Solid-liquid interfacial energy: 0.5 Jm^-2
Latent heat of freezing: 13000 J. mol^-1
Molar volume: 7 × 10^-6 m³ mol^-1

A) 0.36 B) 1.55 C) 3.65 D) 7.30

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Answer & Solution

Answer: Option A

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49

Which of the following is true for martensitic transformation in steels?

A) Symmetry of the product is same as that of the parent phase but the unit cell volume decreases B) Symmetry of the product is different from the parent phase and the unit cell column decreases C) Symmetry of the product is different from the parent phase but the unit cell volume increases D) Symmetry of the product is same as that of the parent phase but unit cell volume increases

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Answer & Solution

Answer: Option C

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50

If the interfacial energy is increase by 10%, the homogeneous nucleation barrier for a spherical particle increases by

A) 10% B) 21% C) 33% D) 100%

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Answer & Solution

Answer: Option C

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Physical Metallurgy MCQ Questions and Answers | Metallurgical Engineering