Quiz:Mechanical Engineering 11 June 2020

Quiz: Mechanical Engineering
Exam: UPPSC AE
Topic: Manufacturing Engineering

Each question carries 3 mark.
Negative marking: 1 mark
Time: 10 Minute

Q1. The stress strain curve for a glass rod during tensile test would exhibit
(a) A straight line
(b) A parabola
(c) A sudden break
(d) None of these

Q2. Ability of a material to exhibit considerable elastic recovery on release of load, is known as:
(a) Toughness
(b) Stiffness
(c) Resilience
(d) Hardness

Q3. Martensite is a supersaturated solution of carbon in:
(a) Alpha iron
(b) Beta iron
(c) Gamma iron
(d) Delta iron

Q4. The crystal structure of Chromium (Cr) at room temperature is
(a) Body-Centered Cubic (BCC)
(b) Face-Centered Cubic (FCC)
(c) Hexagonal Close-Packed (HCP)
(d) Simple Cubic (SC)

Q5. Chills are:
(a) Mixed in sand to enhance its collapsibility
(b) Metallic objects to provide very high heat extraction capability of sand mould
(c) Metallic objects to provide strength of sand mould
(d) Metallic objects to provide very low heat extraction capability of sand mould

Q6. In an Oxy-acetylene welding, the ratio of oxygen to acetylene in reducing flame is
(a) 0.5: 1
(b) 1: 3.1
(c) 1: 1.2
(d) 1: 1

Q7. The merchant circle is used to
(a) Improve the quality of a product
(b) Find the principal stress and principal strain
(c) Fix the price of a product in the market
(d) Establish the shear angle relationship in machining

Q8. Oblique cutting system is also known as:
(a) One-dimensional cutting system
(b) Two-dimensional cutting system
(c) Three-dimensional cutting system
(d) None of these

Q9. Which of the following lathes is suitable for a small engineering workshop involved in repair work?
(a) Center lathe
(b) Tool-room lathe
(c) Special purpose lathe
(d) Capstan lathe

Q10. It is desired to perform the operations like drilling, reaming, counter-boring etc. on a work-piece. Which of the following machines will be used?
(a) Sensitive drilling machine
(b) Radial drilling machine
(c) Gang drilling machine
(d) Multiple spindle drilling machine

Solutions

S1. Ans.(c)
Sol. The stress -strain curve for a glass rod during tensile test would exhibit a sudden break due to brittle failure.

S2. Ans.(c)
Sol. Resilience is the ability of the material to exhibit considerable elastic recovery on release of load.

S3. Ans.(a)
Sol. A meta stable phase of steel formed by transformation of austenite below a temperature 240 Deg C is known as martensite. It is an interstitial solid solution of carbon in α-iron.

S4. Ans.(a)
Sol. Chromium has Body-centered Cubic structure at room temperature. BCC structure has 2 atoms in a unit cell.

S5. Ans.(b)
Sol. There are certain areas in the casting that needs high heat extraction of heat due to variation in geometry of casting. For this purpose, we use chills that provide critical cooling rate.

S6. Ans.(b)
Sol.
1) Neutral flame
Ratio of O2 /C2H2 is 1:1 =2.5 mole oxygen/1 mole C2H2
=31.99×2.5/ 26.037×1
= 3.071:1
2) Carburizing flame
Ratio less than 3.071:1
3) Oxidizing flame
Ratio more than 3.071:1

S7. Ans.(d)
Sol. According to Merchant circle relationship,
2ϕ+β-α=π/2
Or
ϕ=π/4+α/2-β/2
Here, ϕ is shear angle, α is rake angle and β is friction angle.

S8. Ans.(c)
Sol. When the cutting edge of the tool is inclined or making an angle (other than 90°) with the direction of feed, then it is called oblique cutting. This cutting is also called three-dimensional cutting because of force components in all three directions.

S9. Ans.(a)
Sol. For small engineering workshops, which are involved in repair works; center lathe is suitable. The main common tasks that can be performed on center lathe:
1.Facing
2.Turning
3.Drilling
4.Boring
5.Threading
6.Knurling
7. Chamfering

S10. Ans.(c)
Sol. When we place a number of single spindle drilling machine columns together on a common work-table, then the machine is called gang drilling machine.

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