Material Science (Mechanical Properties)

1. The measure of ductility is
(1) Percentage elongation
(2) modulus of resilience
(3) modulus of toughness
(4) ultimate tensile strength
(1)
2. High elastic modulus in materials arises from
(1) weak bonds
(2) high strength of bonds
(3) shall potential well
(4) none of the above
(2)
3. Fine grain sizes are obtained by
(1) fast cooling
(2) slow cooling
(3) increasing nucleation rate
(4) decreasing growth rate
(1, 3, 4)
4. Proof stress corresponds to
(1) elastic limit
(2) lower yield point
(3) higher yield point
(4) a specified strain
(4)
5. In a tensile test, the engineering stress corresponding to the maximum load is termed as
(1) Upper yield stress
(2) Yield strength
(3) Tensile strength as well as UTS
(4) None of the above
(3)
6. In a tension specimen the elongation at the time of fracture is
(1) localized near the ends
(2) localized in the region of necking
(3) delocalized in the centre of the length
(4) none of the above
(2)
7. In a tensile test, necking starts at
(1) Ultimate tensile stress
(2) Lower yield stress
(3) Upper yield stress
(4) None of the above
(1)
8. Increasing strain rate in tension test
(1) decreases yield and ultimate tensile strength
(2) causes yield point to disapper
(3) causes yield point to appear in materials which did not show yield point at low strain rate
(4) none of the above
(3)
9. Which phenomenon is not used in the measurment of hardness?
(1) Wear
(2) Fracture
(3) Scratch
(4) Indentation
(2)
10. Which combination of alloying increases ductility transition temperature?
(1) Si and Mn
(2) C and Fe
(3) C and O2
(3) C and Mn
(3)
11. The method to increase the yield strength of a crystalline material are
(1) Annealing
(2) Grain refinement
(3) Solute additions
(4) None of the above
(2, 3)
12. Which hardness method can measure hardness of a grain?
(1) Knoop
(2) Shore
(3) Rockwell
(4) Vickers (1)

13. If Kf is fatigue strength reduction factor due to stress concentration and K is stress concentration
factor, then fully notch sensitive materials have
(1) Kf = K (2) Kf = 1 (3) Kf < K (4) Kf > K
(1)
14. If q is notch sensitive index, then materials insensitive to notch are characterized by
(1) Kf = 1
(2) Kf = K
(3) Kf = q
(4) Kf > q
(1)
15. In the Griffith equation, the fracture stress is proportional to
(1) C
(2) 2C
(3) C
(4) 1 C
(4)
16. The fatigue strength of mild steel is
(1) equal to its yield strength
(2) lower than its yield strength
(3) equal to its tensile strength
(4) lower than its tensile strength

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(2)

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