Quiz: Mechanical Engineering 9th July

Quiz: Mechanical Engineering
Exam: AE/JE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. Which one of the following methods can be used for forecasting the sales potential of new product?
(a) Time series analysis
(b) Jury of executive opinion method
(c) Sales force composite method
(d) Direct survey method

Q2. The break-even point can be given by the following expression, where, F=fixed cost,V=Variable cost,S=selling cost
(a) F/(1-V/S)
(b) (F-V)/(1-V/S)
(c) V/F
(d) (1-F/S)/F

Q3. While pouring molten metal in the mould if, the molten metal does not appear in the riser. It indicates
(a) a sound casting will be produced
(b) an obstruction between sprue and riser
(c) insufficient molten metal to fill the cavity
(d) either insufficient molten metal to fill the cavity or an obstruction between sprue and riser

Q4. Keeping the surface area constant if the volume of a casting is doubled by changing its design the solidification time is expected to increase by a factor of
(a) √2
(b) 2
(c) 4
(d) 8

Q5. The recrystallization temperature is the temperature at which new strain free grains are formed from the earlier deformed ones. For steel this temperature is close to
(a) 350℃
(b) 560℃
(c) 800℃
(d) 1025℃

Q6. Which of the following processes is used for the manufacturing of steel balls for ball bearings?
(a) die casting
(b) investment casting
(c) cold heading
(d) milling

Q7. In order to get uniform thickness of the plate by rolling process, one provides
(a) camber on the rolls
(b) offset on the rolls
(c) hardening of the rolls
(d) antifriction bearing

Q8. The co-ordination number of BCC crystal structure is
(a) 8
(b) 16
(c) 12
(d) 10

Q9. The defect responsible for the phenomenon of slip, by which most metal deform plastically, is known as
(a) fracture
(b) twinning
(c) dislocation
(d) strain hardening

Q10. Which one of the following pairs of axis lengths (a, b, c) and inter axial angles (α,β,γ) represents the tetragonal crystal system?
(a) a=b=c and α=β=γ=90°
(b) a=b≠c and α=β=γ=90°
(c) a≠b≠c and α=β=γ=90°
(d) a=b=c and α=β=γ≠90°

Solutions

S1. Ans (d)
Sol. Under survey methods surveys are conducted about the consumers’ intentions, opinions of experts, survey of managerial plans, or of markets. Data obtained through these methods are analyzed, and forecasts on demand are made. These methods are generally used to make short-run forecast of demand.

S2. Ans (a)
Sol. Break even cost=S. (F+P)/(S-V) , At Break-even point Profit(P) =0
So, Break even cost= F/(1-V/s)

S3. Ans (d)
Sol. If molten metal does not appear in the riser then it means there is either insufficient molten metal or an obstruction between sprue and riser.

S4. Ans (c)
Sol.
We know that
Solidification time for a casting is given by T=C (V/A)^2
Here, A=Surface area of casting and V= Volume of casting
If we keep surface area constant and doubles the volume then
T_1/T_2 =〖V_1〗^2/〖V_2〗^2
T_2=〖〖T_1.(2V〗_1)〗^2/〖V_1〗^2
T_2=4.T_1

S5. Ans (c)
Sol. Recrystallization temperature of steel is in the range of 500℃-750℃, Which is closer to 800℃.

S6. Ans (c)
Sol. Cold heading process is used to form balls of ball bearings. The figure given below depicts the process.

S7. Ans (a)
Sol. Camber on the rolls is provided to make the plate thickness uniform while doing rolling process. For providing camber, roll is made concave towards the plate/part to be rolled, so that thickness of the plate at the ends will have uniform thickness.

S8 Ans (a)
Sol.
Crystal structure Co-ordination number

1. SC 6
2. BCC 8
3. FCC 12
4. HCP 12

S9. Ans (c)
Sol. A dislocation is the defect responsible for the phenomenon of slip, by which most metals deform plastically. Dislocation is also called line defect. Dislocation is of two types:
Screw Dislocation
Edge Dislocation

S10. Ans (b)
Sol.

Tetragonal Crystal system is shown in figure which depicts that
a=b≠c and α=β=γ=90°

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