Quiz: Mechanical Engineering 2 April 2020

Quiz: Mechanical Engineering

Exam: SSC JE

Topic: Miscellaneous

 

Each question carries 1 mark.

Negative marking: 1/4 mark

Time: 10 Minute

 

Q1. Thermal conductivity of non-metallic amorphous solids with decrease in temperature

(a) increase

(b) decreases

(c) remains constant

(d) may increase or decrease depending on temperature

 

L1Difficulty 3
QTags Mechanical
QCereator Paper Maker 10

 

Q2. Pick up the wrong statement. A refrigerant should have

(a) low specific heat of liquid

(b) high boiling point

(c) high latent heat of vaporization

(d) higher critical temperature

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

Q3. Carbonization of coal is the process of

(a) pulverizing coal in inert atmosphere

(b) heating wood in a limited supply of air at temperatures below 300°C

(c) strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel

(d) binding the pulverized coal into brickettes

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

Q4. The standard atmospheric pressure is 762 mm of Hg. At a specific location, the barometer reads 700 mm of Hg. At this place, what does an absolute pressure of 380 mm of Hg corresponds to?

• 320 mm of Hg vacuum
• 382 mm of Hg vacuum
• 62 mm of Hg vacuum
• 62 mm of Hg gauge

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

 

Q5. For attaining a non-overloading characteristic in centrifugal pumps

• Backward bent vanes are preferred over forward bent vanes
• Forward bent vanes are preferred over backward bent vanes
• Forward bent vanes are preferred over vanes radial at outlet
• Vanes radial at outlet are preferred over backward vanes

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

Q6. Consider two infinitely long blackbody concentric cylinders with a diameter ratio  The shape factor for the outer cylinder with itself will be

(a) 0

(b) 1/3

(c) 2/3

(d) 1

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

Q7. When a body slides down an inclined surface, the acceleration (f) of the body is given by:

(a) f = g

(b) f = g sinθ

(c) f = g cosθ

(d) f =g tanθ

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

Q8. Coriolis component of acceleration depends on

1. Angular velocity of the link
2. Acceleration of the slider
3. angular acceleration of the link

Which of the above is/are correct?

(a) 1 only

(b) 2 only

(c) 1 and 3

(d) 2 and 3

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

Q9. The chief advantage of die casting is

(a) possibility of incorporating thick sections in small castings

(b) castings of inserts is possible

(c) wide tolerances are possible

(d) high production rates are possible

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

Q10. In helium arc welding, the electrode is made of

(a) copper

(b) carbon

(c) mild steel

(d) tungsten

 

L1Difficulty 3

QTags Mechanical

QCereator Paper Maker 10

 

 

 

 

Solutions

 

 

S1. Ans (b)

Sol. Because non-metallic amorphous solids contain air in the voids, so due to decrease in temperature, its thermal conductivity decreases.

 

S2. Ans (b)

Sol.

 

S3. Ans (c)

Sol. Coal carbonization is used for processing of coal to produce coke using metallurgical grade coal. Coal carbonization involves heating of coal in the absence of air.

 

S4. Ans (a)

Sol.

 

mmHg Vacuum

 

 

S5. Ans (a)

Sol. Impeller with backward curved vanes are preferred due to higher efficiency than that of forward curved vanes.

 

S6. Ans.(c)

Sol.

 

 

From geometry

 

 

 

 

 

S7. Ans.(b)

Sol.

f = g sinθ

 

 

S8. Ans.(a)

Sol.

Coriolis acceleration: a_c = 2Vω

Depends upon angular velocity

 

S9. Ans.(d)

Sol.

Advantages of die casting are

(a) Production rate is high

(b) Unit cost per component is less

(c) Edged gated components can also be placed symmetrically around injection center line

 

Disadvantages of die casting are

(a) Initial investment is more

(b) with increase in number of cavities, the feed balancing and thermal balancing becomes more complicated.

 

S10. Ans.(d)

Sol. Helium arc welding is TIG welding, with helium as shielding gas, uses the electrode made of tungsten.

 

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