Test: Basic Concepts (Structure Of Solids), Hardness Test & Crystalline Materials - 2 - Mechanical Engineering MCQ

Which of the following would you prefer for checking the hardness of very thinsections? 

Assertion (A): Unlike in the case of ionic bonds, the co-ordination numbers for covalently bonded atoms are not controlled by the radii ratio.  
Reason (R): A covalent bond has a specific direction of bonding in space.

Magnesium is extruded and not rolled because  

With the increase of percentage of carbon in the steel, which one of the following properties does increase? 

For a Rhombohedral space lattice, which one of the following is correct? 

Which one of the following pairs is not correctly matched? 
Space Lattice          Relation between Atomic radius r and Edge element a

Match List-I (Name of the Element) with List-II (Crystal Structure) and select the correct answer using the codes given below the lists: 
List I                                                          List II
A. Fluorspar                                    1. Body-centered cubic
B. Alpha-Iron                                   2. Hexagonal closed packed
C. Silver                                          3. Simple cubic
D. Zinc                                            4. Face-centered cubic
Codes: A B C D                      A B C D
       (a) 3 2 4 1                   (b) 4 1 3 2
       (c) 4 2 3 1                   (d) 3 1 4 2

Match List-I (Element) with List-II (Crystal Structure) and select the correct answer using the code given below the Lists:  
List - I                                                     List - II
A. Alpha Iron                                     1. Hexagonal closed packed
B. Copper                                          2. Body-centred cubic
C. Zinc                                               3. Amorphous
D. Glass                                            4. Face-centred cubic
Codes: A B C D                             A B C D
       (a) 2 3 1 4                          (b) 1 4 2 3
       (c) 2 4 1 3                          (d) 1 3 2 4 

In the atomic hard-sphere model of the crystal structure of Copper, what is the edge length of unit cell? 

The coordination number for FCC crystal structure is 

Assuming atoms to be perfect spheres, what is the value of the highest possible atomic packing factor (APF) in metals?  

Which one of the following is correct for 'Climb'?  

What is the movement of block of atoms along certain crystallographic planes and directions, termed as? [IES 2007]

What is a surface imperfection, which separates crystals of different orientationsin a poly-crystalline aggregate, called? [IES-2008]

Assertion (A): Refining the grain size of a polycrystalline material renders itharder and stronger. 
Reason (R): Grain boundaries provide easy paths to dislocation motion.

Which one of the following is correct for "Burger's vector" in screw dislocation?  

Chemicals attack atoms within grain boundaries preferentially because they have

What is the approximate strain energy expression for a dislocation of unit length, irrespective of its edge or screw character?

A screw dislocation  
1. Lies parallel to its Burger's vector
2. Lies perpendicular to its Burger's vector
3. Moves in a perpendicular direction to the Burger's vector
4. Moves in an inclined direction to the Burger's vector
Select the correct answer using the codes given below:
Codes:

Which one of the following statements is correct in the case of screw dislocations?(= Burgers Vector; = Imaginary Vector) 

Which of the following factors govern solubility of two non-ferrous metals both inliquid state, as well as in solid state?  
1. Crystal structure
2. Relative size factor
3. Chemical-affinity factor
4. Relative valence factor
Select the correct answer using the codes given below:
Codes:

Which one of the following pairs is not correctly matched?  

Assertion (A): Carbon forms interstitial solid solution when added to iron.Reason (R): The atomic radius of carbon atom is much smaller than that of iron. 

Which one of the following defects is 'Schottky defect’? 

Which of the following is a point imperfection? 
1. Vacancy
2. Interstitialcy
3. Frenkel imperfection
4. Schottky imperfection

Consider the following statements about FCC and HCP crystal structure:
1. Both have same coordination number and atomic packing fraction.
2. Both represent closely packed crystal structures.
3. Both structures are generated by stacking of close packed plants on top of one another,but only the stacking sequence is different.
Which of the statements given above are correct?

Which of the following properties of a solid are dependent on crystal imperfecttions? 
1. Yield stress
2. Melting point
3. Semiconductivity
4. Ductility
Select the correct answer using the codes given below: