SSC-JUNIOR ENGINEER (Civil & Structural) Online Exam 2016

Paper-I

Total Questions: 50

31. The void ratio of a soil sample having a porosity of 0.32 and a moisture content of 25% will be _________.

Correct Answer: B. 0.47
Solution:Void ratio,

32. A loose uniform sand with rounded grains has effective grain size of 0.05 cm. Co-efficient of permeability of the sand is ________.

Correct Answer: A. 0.25 cm/sec
Solution:No explanation given in the book

33. Which of the following factors can affect the bearing capacity of the soil?

Correct Answer: D. All options are correct
Solution:No explanation given in the book

34. Which of the following soils has the uniformity coefficient of more than 10?

Correct Answer: A. Well graded soil
Solution: Uniformity Coefficient: This is the ratio of the maximum size of the smallest 60 per cent (D₆₀) to the effective size. It is a numerical measure of soil uniformity and was first proposed by Hazen and so it is sometimes called Hazen coefficient. It is a measure of the particle size range.

If the Hazen uniformity coefficient is less than 4 or 5, the soil is considered uniform in particle size, which means that all particle sizes fall within a narrow range. Well-graded soils have uniformity coefficients greater than 10 and have a continuous, wide range of particle sizes.

35. An odd shaped body weighing 7.5 kg and occupying 0.01 cubic metre volume will be completely submerged in a fluid having specific gravity of _______.

Correct Answer: D. 0.75
Solution:No explanation given in the book

36. A ship's model of scale 1 : 100 has a wave resistance of 1 N at its design speed. The corresponding wave resistance (in N) in prototype will be _________.

Correct Answer: C. 1000000
Solution:No explanation given in the book

37. If the capillary rise of water in a 1 mm diameter tube is 3 cm, the height of capillary rise of water in a 0.2 mm diameter tube in centimetre will be _________.

Correct Answer: C. 15
Solution:

38. The pressure intensity is same in all directions at a point in a fluid __________.

Correct Answer: D. when there is no relative motion of one fluid layer relative to other
Solution:

Equation (i) is independent of θ, therefore it is proved that pressure acts equally in all directions in a stationary fluid.

39. Flow at constant rate through a tapering pipe is ___________.

Correct Answer: B. steady and non-uniform flow
Solution:Non-Uniform Flow

When the velocity and other hydrodynamic parameters change from one point to another the flow is defined as non-uniform.

Important points:

1. For a non-uniform flow, the changes with position may be found either in the direction of flow or in directions perpendi-cular to it.

2. Non-uniformity in a direction perpendicular to the flow is always encountered near solid boundaries past which the fluid flows.

Four Possible Combinations of Flow

TypeExample
1. Steady Uniform FlowFlow at constant rate through a duct of uniform cross-section (the region close to the walls of the duct is disregarded).
2. Steady Non-uniform FlowFlow at constant rate through a duct of non-uniform cross-section (tapering pipe).
3. Unsteady Uniform FlowFlow at varying rates through a long straight pipe of uniform cross-section (again the region close to the walls is ignored).
4. Unsteady Non-uniform FlowFlow at varying rates through a duct of non-uniform cross-section.

40. The motion of air mass in a tornado is a ____________.

Correct Answer: D. forced vortex at centre and free vortex outside
Solution:A vortex is a rapidly spinning, circular or spiral flow of fluid around a central axis. The swirling motion tends to suck everything within the fluid toward its centre. The speed and the rate of rotation of the fluid are greatest at the centre, and decrease progressively with distance from the centre.

Tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud. A less violent version of a tornado, over water, is called a waterspout. The motion of air mass in a tornado is a forced vortex at centre and free vortex outside.