Quiz: Mechanical Engineering 6th May

Quiz: Mechanical Engineering
Exam: DFCCIL
Topic: Fluid Mechanics

Each question carries 2 mark
Negative marking: 1/3 mark
Time: 10 Minutes

Q1. The property of material, which enables it to withstand bending without fracture, is known as
(a) Mechanical strength
(b) Stiffness
(c) Flexural rigidity
(d) Ductility

Q2. The notch angle of Izod impact test specimen is
(a) 10º
(b) 20º
(c) 30º
(d) 45º

Q3. The solidification of liquid at constant temperature into two phase mixture is called
(a) Peritectic reaction
(b) Eutectoid reaction
(c) Hypo Eutectoid reaction
(d) Eutectic reaction

Q4. Vectorial sum of the Burgers vector of dislocations meeting at a nodal point is
(a) zero
(b) 1
(c) –1
(d) none of the above

Q5. If plain carbon steel in the austenitic condition is quenched in water to room temperature, its structure changes from ‘austenite’ to
(a) Pearlite
(b) Martensite
(c) Cementite
(d) Ferrite

Q6. Which is the isothermal reversible reaction in which a solid phase is converted into two or more intimately mixed solids on cooling?
(a) Peritectoid
(b) Peritectic
(c) Eutectic
(d) Eutectoid

Q7. The supersaturated interstitial solid solution of carbon in alpha iron is known as
(a) martensite
(b) pearlite
(c) bainite
(d) ferrite

Q8. Pearlite is a combination of:
(a) Ferrite and cementite
(b) Cementite and gamma iron
(c) Ferrite and austenite
(d) Ferrite and iron graphite

Q9. Which of the following scale is not used to measure the hardness of very hard materials?
(a) Rockwell ‘C’ scale
(b) Brinell hardness scale
(c) Rockwell ‘A’ scale
(d) Rockwell ‘B’ scale

Q10. Toughness of steel is increased by adding:
(a) Nickel
(b) Sulphur
(c) Chromium
(d) Tungsten

Solutions

S1. Ans(c)
Sol. The property of material, which enables it to withstand bending without fracture, is known as flexural rigidity.

S2. Ans(d)
Sol. The notch angle of Izod impact test specimen is 45°.

S3. Ans(d)
Sol. The solidification of liquid at constant temperature into two phase mixture is called Eutectic reaction.

S4. Ans(a)
Sol. Vectorial sum of the Burgers vector of dislocations meeting at a nodal point is zero.

S5. Ans(b)
Sol. When plain carbon steel in the austenitic condition is quenched in water to room temperature, its structure change to Martensite.

S6. Ans(d)
Sol. A solid phase is converted into two or more intimately mixed solids on cooling as-
Peritectic reaction: Liquid + solid 1 → solid 2
Peritectoid reaction: solid 1 + solid 2 → solid 3
Eutectic reaction: Liquid 1 → solid 2 + solid 3
Eutectoid reaction: solid 1 → solid 2 + solid 3
Monotectic reaction: Liquid 1 → liquid 2 + solid

S7. Ans(a)
Sol. Martensite is a supersaturated solution of carbon and body centered tetragonal (BCT) ferrite (alpha iron). BCT is a modified BCC crystal stricture where height of crystal is increased.

S8. Ans(a)
Sol. Pearlite consists of 87% ferrite (layer are thick) and 13% cementite (thin layer) arranged alternatively in a lamelle formation.

S9. Ans(d)
Sol. Rockwell ‘B’ scale is not used to measure the hardness of very hard materials.

S10. Ans(a)
Sol. Toughness of steel is increased by adding nickel.