Question

Dental Materials MCQS - Physical Properties

1. Stress is defined as:
A. An applied load or force
B. A deformation resulting from an applied load
C. An external force opposing an applied load
D. An internal force opposing an applied load

2. Strain is defined as :
A. An applied load or force
B. A deformation resulting from an applied load
C. An external force opposing an applied load
D. An internal force opposing an applied load



3. The proportional limit is defined as :
A. The maximum stress in a structure
B. The minimum force required to cause a structure to break
C. The maximum stress that can be induced without permanent deformation
D. The maximum elongation under tension that can be measured before failure

4. The modulus of elasticity is defined as:
A. The stress at the proportional limit
B. The strain at the proportional limit
C. The stress/strain ratio within proportional limit
D. None of the above

5. Compressive stress is computed by dividing the external force by the :
A. Area of the test specimen upon which the weight rests
B. Elasticity of the test specimen in strain
C. Length of the test specimen beneath the force
D. Strain of the test specimen per unit length

6. The greatest stress which can be produced in a material such that stress is directly proportional to strain is called :
A. The elastic limit
B. The proportional limit
C. The yield strength
D. Modulus of elasticity

7. The point at which stress of a material exhibits a specific limited deviation P is called :
A. Proportional limit
B. Tensile strength
C. Ultimate strength
D. Yield strength

8. Hardness number which does not depend upon the ductility of metal is :
A. Knoop Hardness Number (KHN)
B. Vicker's Hardness Number (VHN)
C. Rockwell Hardness Number (RHN)
D. Brinells Hardness Number (BHN)

9. Ability of an orthodontic wire to spring back to its original shape is evaluated by :
A. Brittleness
B. Resilience
C. Tensile strength
D. Toughness

10. Brinnel hardness number of a dental gold alloy is directly proportional to its :
A. Tensile strength
B. Elongation
C. Modulus of elasticity
D. Modulus of resilience



11. Ultimate tensile strength refers to :
A. Stress before rupture
B. Shear strain
C. Longitudinal compressive strength
D. Horizontal compressive strength

12. When solid gets wet completely, contact angle is :
A. 90 degrees
B. 0 degree
C. 0 - 90 degrees
D. Greater than 90 degrees

13. Property of the material which describes the resistance to abrasion is :
A. Hardness
B. Yield strength
C. Modulus of elasticity
D. None of the above

14. Modulus of elasticity means :
A. Rigidity or stiffness of the material
B. Ability to be stretched with permanent deformation
C. Ductility of a material
D. Malleability of a material

15. A material behaves in certain ways above and below the proportional limit on a stress strain curve. Which of the following is correct ?
A. Above the proportional limit, a material functions in a plastic manner ; whereas below the proportional limit, it behaves as an elastic
B. Above the proportional limit, a material functions in an elastic manner ; whereas below the proportional limit, it behaves as a plastic
C. Either A or B
D. Neither A nor B

16. Sublimation is the conversion of a :
A. Solid directly into gas
B. Gas to liquid and then to solid
C. Gas directly to liquid
D. Solid to liquid and then into gas

17. Which of the folllowing physical property can be used to estimate indirectly the proportional limit of gold alloys ?
A. Vickers hardness number
B. Knoop hardness number
C. Brinell hardness number
D. Rockwell hardness number

18. Ductility of a material is a measure of its :
A. Grain elongation
B. Annealing
C. Cold working
D. Work hardening

19. The ability of an alloy to withstand mechanical stresses without permanent deformation is reflected by its :
A. Resilience
B. Elastic limit / Elastic strain
C. Hardness
D. Fatigue resistance

20. The stiffness of a dental gold alloy is determined by its :
A. Proportional limit
B. Modulus of elasticity
C. Ultimate tensile strength
D. Flow​

Answer 1

Explanation:

A deformation resulting from an applied load

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Answer 2

Answer:

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