A. Quartz
B. Cristobalite
C. Tridymite
D. Corundum
Related Mcqs:
- Absolute refractory period in heart______________?
A. Lasts till cardiac contraction
B. Longer than refractory period in skeletal muscle
C. A phase of cardiac cycle in which heart cannot be stimulated by any amount of stimulus
D. Corresponds with duration of action potential
E. All of the above - The absolute refractory period of an action potential is due to _______________?
A. Insufficient neurotransmitter
B. Depletion of intracellular Na+
C. Inactivation of Na+ k+ ATPase
D. Voltage inactivation of the Na+ channel - All of the following statements about cast cobalt alloy are true EXCEPT_____________?
A. They have a modulus of elasticity twice that of gold alloys
B. They are more rigid than gold alloys
C. They have higher ductility than gold alloys
D. They have a lower proportional limit than gold alloys - Which of the following is function of fluoride flux in soldering process ?
A. It prevents the formation of copper oxide
B. It prevents the formation of chromium oxide or dissolves chromic oxide layer
C. It prevents the flow of material in undesirable area
D. Increase the strength of solder - Which one of the following elements is NOT added is small amount to be used as grain refiners ?
A. Iridium
B. Ruthinium
C. Indium
D. Platinum - Which of the following cast gold alloys is used for fabricating partial denture frameworks______________?
A. Type I – Soft
B. Type II – Hard
C. Type III – Hard
D. Type IV – Extra Hard - Which of the following decrease with strain hardening______________?
A. Surface hardness
B. Strength
C. Proportion limit
D. Corrosion resistance - Which one of the following categories of dental materials has the highest thermal conductivity_________________?
A. Unfilled acrylic plastics
B. Gold alloys
C. Porcelains
D. Zinc phosphate cements - Which of the following is correct________________?
A. Type I and Type II gold can be heat treated and annealed
B. Type III and Type IV gold can be heat treated and annealed
C. Type I and IV gold can be heat treated and annealed
D. All the type of gold can be heat treated and annealed - Which one of the following is most elastic ?
A. a titanium
B. B titanium
C. Chrome-cobalt-nickel
D. Nickel-titanium
