A. Silica
B. Quartz
C. Cristobolite
D. Calcium sulphate monohydrate
Related Mcqs:
- Binder in phosphate bonded investment is______________?
A. Magnesium oxide & Phosphate
B. Magnesium oxide & Phosphoric acid
C. Magnesium oxide & Monoammonium phosphate
D. Magnesium oxide & Ortho Phosphoric acid - The product, which is obtained by calcining gypsum under steam pressure at 120-130°C or by dehydrating gypsum in the presence of sodium succinate is_______________?
A. Alpha – hemihydrates
B. Beta – hemihydrates
C. Calcium sulphate dihydrate
D. Orthorhombic anhydrate - Gypsum bonded investment should not be heated over______________?
A. 700°C
B. 1,300°C
C. 1,063°C
D. 900°C - Quartz is added to gypsum bonded investment to______________?
A. Increase the strength
B. Counter balance contraction of gypsum during heating
C. aid in hygroscopic expansion
D. Increase the shelf life of investment - The best pickling solution for gypsum bonded investment is_______________?
A. Hydrochloric acid
B. Nitric acid
C. Sulphuric acid
D. Phosphoric acid - The strength of a gypsum investment is dependent on_______________?
A. Carbon content
B. Silica content
C. Gypsum
D. Copper - A thinner mix of a gypsum bonded investment will_______________?
A. Produce a smoother casting
B. Decrease setting expansion
C. Increase setting expansion
D. Increase thermal expansion - Accelerators and retarders are used with gypsum products mainly to control_______________?
A. Setting time
B. Setting expansion
C. Hardness of the set product
D. None of the above - Type III Dental gypsum is__________________?
A. Class II stone
B. Densite
C. Class I stone or hydrocal
D. Model or lab plaster - Gypsum product having least expansion_____________?
A. Impression plaster
B. Model plaster
C. Stone plaster
D. Die stone
