Structure of matter l Dental materials MCQs

 

Structure of matter l Dental materials MCQs (multiple choice question) for dental students

MCQ on structure of matter for dental materials

(1)Fraction of space occupied by the atoms In a unit call of s space lattice is:

a. Interatomic distance.

b. coordination number.

C. Atomic packing factor.

(2) Amorphous solids are characterized by having:

a. High internal energy.

b. Atomic weight.

c. Random and short order arrangement

d. Definite melting temperature.

e. Specific shape and form in their structure.

(3) Crystalline solids are characterized by having:

a. Low internal energy.

b. Random and short order arrangement

c. Glass transition temperature.

d. Specific shape and form in their structures

(4) For secondary bond to occur, there must be:

b. Electrons share,

a. Electrons cloud.

c. the core.

d. Dipole.

(5) Basic bond for ceramics is:

a. Ionic bond

b. Covalent bond.

c. Metallic bond.

d. Secondary bond

6) Material with strong interatomic  bonds will have:

a. High strength

C. High meting temperature.

d. High hardness.

(7) Metals are electrical conductor due to presence of:

a. Cloud of electrons.

b. Low coefficient of thermal expansion

c. Shared electrons.

d. +ve & -ve ions.

(8) Theoretical strength of the materials is higher than the actual strength due to:

a. All of the above.

b. High atomic packing factor. &. Presence of crystal defects

c. Regularity in atomic arrangement.

d. None of the above

(9) Basic bond for polymer is:

a. Tonic bond

b. Covalent bond.

c. Metallic bond

d. Secondary bond

True and false on structure of matter for dental materials

(1) Glasses have definite melting temperature

(2) The coefficient of thermal expansion of a material is directly proportional to its melting  temperature

3) Covalent bonds result from sharing of electrons

(4) Reconstructive transformation of silica needs less energy, occurs rapidity and involves breakage of bonds

(5) Materials have higher atomic packing factor, have higher strength and lower density.

(6) Materials with high interatomic forces of attraction will have high strength and high coefficient of thermal expansion.

(7) The diffuse nature of electrons in metallic bond is responsible for high thermal conductivity and easy deformation of metals.

(8) Displacive transformetion of silica from alpha to beta form is always accompanied by thermal expansion.

(9) Polymers are molecular solids where the primary covalent bonds influence their mechanical properties

(10) The different polymorphic forms of silica have the same physical properties and different chemical properties

(11) Amorphous solids have their constituent atoms regularly arranged with repetition in the three dimensions in crystal lattice.

(12) As the atomic weight of the material increases, its density increases.

(13) Reconstructive transformation is accompanied by volumetric changes.