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

GENERAL ENGINEERING CIVIL AND  STRUCTURAL

Total Questions: 50

41. The overflowing sheet of water on a weir is called:

Correct Answer: C. nappe
Solution:In hydraulic engineering, a nappe is a sheet or curtain of water that flows over a weir or dam. The upper and lower water surface have well-defined characteristics that are created by the crest of a dam of weir

42. What is the effect of fly ash in concrete?

Correct Answer: A. Reduces the heat of hydration
Solution:The replacement of cement by fly ash reduces the heat of hydration in concrete structures. This reduces the thermal gradient, and therefore the chance of thermal cracking is reduced.

43. Match the items in List-I (names of quantities) with those in List-II (units of quantities in the SI system). Use codes in List for matching.

List-IList-II 
(a) Dynamic viscosity(i) N/m
(b) Kinematic viscosity(ii) N.m
(c) Surface tension(iii) N.s/m²
(d) Energy(iv) m²/s

 

(a)(b)(c)(d)
A.(iii)(iv)(ii)(i)
B.(iii)(iv)(i)(ii)
C.(iv)(iii)(i)(ii)
D.(ii)(iv)(i)(iii)
Correct Answer: B.
Solution:Dynamic Viscosity: It is the property of a fluid which offers resistance to the movement of one layer of fluid over an adjacent layer of the fluid.
  • Its SI unit is N·s/m² or Pa·s.
  • Its C.G.S. unit is Poise.
  • 1 Poise = 0.1 Pa-s = 0.1 N-s/m²

Kinematic Viscosity: The ratio of dynamic viscosity to density appears frequently and this ratio is given by the name kinematic viscosity.  ρ

Kinematic Viscosity (γ) = Dynamic viscosity (μ)/density (ρ)

  • Its SI unit = m²/s.
  • Its C.G.S unit = Stoke or cm²/s
  • 1 Stoke = 104 m²/s

Surface tension is defined as the work, dW, required to expand a surface by dA. It is, thus, a direct measure of the energy needed to form a new surface of unit area, i.e., surface energy. Surface tension is generally expressed in N/m (SI unit).

Energy, in physics, the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms. Energy is generally expressed in N.m (SI unit).

44. The failure of an an over reinforced concrete beam is due to:

Correct Answer: B. compression failure
Solution:The primary failure (occurs first) in an over reinforced beam is compression failure, as the crushing of concrete occurs before yielding of the tension reinforcement.

Primary compression failure mean's first concrete will fail in compression, secondary compression failure means first steel will fail in tension and after that concrete will fail in compression because it will reach its permissible value first than steel, that's why it is primary compression failure.

45. The bearing of a line AB is 150º 15' and the angle ABC between line AB and BC is 110º 30' as shown in the given figure:

What is the bearing of line BC?

Correct Answer: D. 80º 45'
Solution:

46. A canal was designed for a full supply discharge of 60 cumec. The average supply discharge in the canal is 40 cumec.

The capacity factor of the canal is:

Correct Answer: B. 0.67
Solution:

47. The ability of a material to endure alternate wet and dry conditions for a long period without considerable deformation and loss of mechanical strength is called:

Correct Answer: B. weathering resistance
Solution:Weather resistance is the ability of a material to withstand alternating wet and dry conditions. For a long period without considerable distortion and loss of mechanical strength.

48. Which of the following Indian Standard Codes provides conservatively imposed loads for buildings and structures?

Correct Answer: C. IS 875 (part 2)-1987
Solution:IS: 875 in the following five parts:

Part 1 Dead loads
Part 2 Imposed loads
Part 3 Wind loads
Part 4 Snow loads
Part 5 Special loads and load combinations

This Code (Part 2) deals with imposed loads on buildings produced by the intended occupancy or use.

49. The saturation capacity, field capacity and the permanent wilting point of a soil are 47%, 27% and 14%, respectively. The available moisture for the crops grown in the soil is:

Correct Answer: B. 13%
Solution:Available moisture content (A.M.) = Field capacity (F.C.) - Permanent wilting point (PWP) = 27 - 14 = 13%.

50. Which of the following laws states that pressure or intensity of pressure at a point in static fluid is equal in all directions?

Correct Answer: B. Pascal's law
Solution:Pascal's law states that the intensity of pressure at a point in a fluid at rest is equal in all directions.

According to the law, when a certain pressure is applied at any point in a fluid, which is at rest, the pressure will get equally transmitted in all directions and to every other point in the fluid. This unique property of fluid static pressure can be proved by considering the forces acting on any arbitrary fluid element.

The above equation shows that the pressure at any point in x, y and z directions is equal.

Since the choice of fluid element was completely arbitrary, which means the pressure at any point is the same in all directions.