SSC-JUNIOR ENGINEER (Civil & Structural) Online Exam 2020 (Exam held on 23/03/2021) (Part-IV)

GENERAL ENGINEERING CIVIL AND  STRUCTURAL

Total Questions: 50

11. A real fluid in which the shear stress is directly proportional to the velocity gradient is known as:

Correct Answer: A. Newtonian fluid
Solution:

1. Ideal Fluid: A fluid, which is incompressible and having no viscosity, is known as an ideal fluid. Ideal fluid is only an imaginary fluid as all the fluids, which exist, have some viscosity.

2. Real Fluid: A fluid, which possesses viscosity, is known as real fluid. All the fluids, in actual practice, are real fluids.

3. Newtonian Fluid: A real fluid, in which the shear stress is directly proportional to the rate of shear strain (or velocity gradient), is known as a Newtonian fluid.

4. Non-Newtonian Fluid: A real fluid, in which the shear stress is not proportional to the rate of shear strain (or velocity gradient), known as a Non-Newtonian fluid.

5. Ideal Plastic Fluid: A fluid, in which shear stress is more than the yield value and shear stress is proportional to the rate of shear strain (or velocity gradient), is known as ideal plastic fluid.

12. A cantilever beam of span L is built-in at the support. It is restrained against lateral deflection and torsion at the free end. The effective length of compression flange for the beam as per IS 800:2007 is:

Correct Answer: D. 0.5 L
Solution:

13. A newly built house is let out for a rent of ₹1,000 per month inclusive of all taxes. If outgoings are at 20% of the gross rent and expected rate of return is 10%, what is the capital value by the rental method of valuation?

Correct Answer: D. ₹ 96,000
Solution:No explanation given in the book

14. The following two statements pertain to a simply supported under reinforced concrete beam. Select the correct option with regard to these statements:

1. The failure of the beam takes place due to the yielding of steel

2. The moment of resistance of the beam is more than that of the balanced section of the beam.

Correct Answer: B. Statement 1 is true but Statement 2 is false
Solution:No explanation given in the book

15. If p is internal pressure, d is diameter and t is thickness of wall for a thin cylindrical shell, then the value of hoop stress will be:

Correct Answer: D. pd/2t
Solution:
  • Consider a thin pressure vessel having closed ends and contains fluid under a gauge pressure P, then the walls of the cylinder will have longitudinal stress, circumferential stress and radial stress.
  • As shown in the figure, a point of the shell having stresses from all sides i.e., triaxial stresses.

16. If the quadrantal bearing of a line AB is S 31º35' E, then its whole circle bearing is equal to:

Correct Answer: D. 148º25'
Solution:Quadrantal bearing of line AB is S 31 º35' E

Whole circle bearing (WCB) = 180 º - 31º 35'

17. Which constituent in cement is to be kept minimum to avoid a sulphate attack?

Correct Answer: A. C₃A
Solution:C₃A is fragile to the sulphate attack. Cement should contains less than 5% C₃A as C₃A affect the setting time of cement.

18. If the bearing of the side AB of a regular hexagon traverse ABCDEFA shown in the figure is 36º45' the bearing of the adjacent side BC of the traverse is:

Correct Answer: A. 96º45'
Solution:

19. Classify the following pollutants as primary pollutants (PP) and secondary pollutants (SP). Ozone, Carbon monoxide, Particulate matter, Photochemical smog, Nitrogen oxides, Aerosol/mist, Hydrocarbons, Peroxy-Acetyl-Nitrate, Sulphur dioxide.

Correct Answer: A. PP: Carbon monoxide, Particulate matter, Nitrogen oxides, Hydrocarbons, Sulphur dioxide SP: Ozone, Photochemical smog, Aerosol/mist, Peroxy-Acetyl-Nitrate
Solution:Primary air pollutants: Materials that when released pose health risks in their unmodified forms or those emitted directly from identifiable sources.

Five major materials released directly into the atmosphere in unmodified forms:

  • Carbon monoxide
  • Sulphur dioxide
  • Nitrogen oxides
  • Hydrocarbons
  • Particulate matter

Secondary air pollutants: Primary pollutants interact with one another, sunlight, or natural gases to produce new, harmful compounds.

Four major secondary pollutants are:

  • Ozone
  • PAN (peroxy acetyl nitrate)
  • Photochemical smog
  • Aerosols and mists (H₂SO₄).

20. What is the SI unit for dynamic viscosity?

Correct Answer: C. Pascal second
Solution:The SI unit for dynamic viscosity η is the Pascal-second (Pa-s), which corresponds to the force (N) per unit area (m²) divided by the rate of shear (s⁻¹). Just as in the definition of viscosity

η = F/A / ẏ.