## Machine Design Questions and Answers Part-1

1. Which of the following parameters can be obtained by tension test of a standard specimen?
a) Proportional Limit
b) Yield Strength
c) Percentage Reduction in area
d) All of the mentioned

Explanation: Tension test determines the parameters related to stress strain curve and also reduction and elongation in area and length can be found respectively.

2. Proportional Limit is defined as the stress at which the stress strain curves begins to deviate from the straight line.
a) True
b) False

Explanation: Proportional limit is the point of deviation in stress strain curve.

3. Which of the following is the definition of Compliance?
a) Inverse of Rigidity
b) Inverse of Stiffness
c) Proportional to elastic Limit
d) None of the mentioned

Explanation: Compliance is a parameter which is the inverse of stiffness.

4.Yield strength is defined as the maximum stress at which a marked increase in elongation occurs without increase in________
b) Strength
c) Toughness
d) Hardness

Explanation: Yield strength is the strength at which strain increases. Now as the strength is constant, therefore load is constant.

5. For the materials which do not exhibit a well-defined yield points, the yield strength is defined as the stress corresponding to a permanent set of how much percentage of gauge length?
a) 0.1
b) 0.2
c) 0.3
d) 0.4

Explanation: Generally for all the practical purpose, an offset of 0.2% of gauge length is considered.

6. Proof strength is defined as the stress which will produce a permanent extension of how much percentage in the gauge length of the standard test specimen.
a) 0.1
b) 0.2
c) 0.3
d) 0.4

Explanation: Proof strength is used in design of fasteners. It corresponds to 0.1% permanent deformation of gauge length.

7. All engineering materials are plastic.
a) True
b) false

Explanation: Yes all the existing engineering materials are plastic to some extent.

8. Which of the following are true about plasticity?
a) Permanent Deformation
b) Ability to retain deformation under load or after removal of load
c) Plastic deformation is greater than elastic deformation
d) All of the mentioned

Explanation: This is the basic definition of plasticity.

9. Which of the following is measure of stiffness?
a) Modulus of elasticity
b) Modulus of plasticity
c) Resilience
d) Toughness