1001. The attraction between atoms or molecules because of van der Waals forces is due to?
A. magnetic oscillations
B.a static electron field
C.a fluctuating dipole
D.the sharing of a valence electron
E.electron rotation

1002. Which of the following is formed when gypsum is calcined at temperatures 500°C?
A. Orthorhombic anhydrite
B.Calcium sulfate dihydrate
C. Calcium sulfate hemihydrate
D. Hexagonal anhydrite

1003. The filler used in impression compound is?
A. bees wax
B.zinc phosphate
C.French chalk
D.guttapercha
E.zinc phosphate powder

1004. Which of the following impressions can be most safely transported to the dental laboratory?
A.Polysullides
B.Alginates
C.Addition silicones
D.Agar hydroColloids
E.Condensation silicones

1004. The flux used when casting gold alloys?
A. helps to prevent oxidation of the alloy
B.contains borax and boric acid
C.increases fluidity of the metal
D.all of the above
E.none of the above

1005. Lattice imperfections of metal structures, in which a lattice position is left vacant, are termed ?
A. interstitial point detects
B.vacancies
C.edge dislocations
D.line defects
E.nonequilibrium defects

1006. Gold alloys used for the fabrication of saddle bars and clasps, are?
A. Type I
B.Type II
C.Type III
D.Type IV

1007. The plasticizer commonly used in non-aqueous elastomeric impresion materials is?
A.dibutyl phthalate
B.colloidal silica
C.alkyl silicate
D.silane oligomer

1008. Denture cleansers which clean by liberating oxygen, contain?
A. sodium chloride
B.sodium peroxide
C.soda ash
D.sodium sulfite
E.sodium perborate

1009. The average particle size of modern dental amalgam alloys is?
A.0.05 -0.9 micrometer
B.1-5 micrometer
C.100 -140 micrometer
D. 25-35 micrometer

1010. Concentrations higher than 50% of phosphoric acid are not used for acid etching, as this would?
A. form a protective layer on enamel which protects the tooth from further dissolution
B.lead to massive decalcification of enamel rods
C.damage the pulp
D.make the etching process too fast to comfort

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