DRDO STA Computer Science Civil Tier 2 Mock Test- 2 Free Online Test 2026

Free flow speed (V_f) is that speed at which flow and density is negligible

Examples of intrusive igneous rocks are diorite, gabbro, granite, pegmatite, and peridotite.

Examples, of extrusive igneous rocks andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff.

1) Measurement suspended solid is done by a gravimetric test involving the mass of residual measurement.

2) Measurement of Turbidity: -

A) Based on absorption principles

i) Turbidity Rod

ii) Jackson’s Turbidity meter

iii) Baylis Turbidimeter

B) Based on the scattering principle

i) Modern Nephelometer

3) Through Nessler’s tubes on Burgess scale, true colour is measured.

Height of capillary rise is given by,

Reason for the bulking of sand

• The reason is that moisture causes a film of water around sand particles which results in the increase of the volume of sand
• For a moisture content percentage of 5 to 8, there will be an increase in volume up to 20 to 40 per cent depending upon the sand
• If the sand is finer there will be more increase in volume

1. For Plain and Rolling terrains (bound by snow) = 7%

2. For hilly roads not bound by snow = 10%

3. Urban roads with frequent intersections = 4%

• The groundwater supplied is generally pure and safer, because of the water before getting sorted in the underground reservoir, undergoes natural filtration during percolation through the soil pores.

• These water are free from suspended impurities and organic matter but may contain greater amounts of dissolved salts, minerals, hardness, odors, and carbon dioxide.

∴ Groundwater ⇒ Carbon dioxide and hardness

Lake Water:

• Water in the lake is still and there is no circulation or movement of water molecules. Thus water at the surface will have a high amount of dissolved oxygen and very less D.O at the bottom.

• All the particulates, pigments and impurities settle down and thus the bottom level water is highly contaminated.

∴ Lake Water ⇒ Low D.O. and color

Canal water:

• Although canal comes out from the river, and is supposed to contain a high amount of organic matter. It has a lower content of such impurities due to self-purification ability of pure water.

• Since it is open to the surface, will have great amount of dissolved oxygen into it.

Canal Water ⇒ Low organic content and high D.O.

Settling velocity for particle size less than 0.1 mm,

V_s in mm/s,
d in mm
T temperature of water in °C,

Indirect methods are quicker, cheaper and less laborious than the direct method.

In this method, a series of guide points are selected along with a system of straight lines and their elevations are determined.

These points are then plotted, and contours are drawn by interpolation.

Three methods used for interpolation are as follows:

i) By Estimation

This is a rough method and is used on a small-scale map.

ii) By Arithmetic Calculations

This is a very accurate method but a tedious one. The position of contours points between guide points is located by arithmetic calculations.

iii) By Graphical Method

This is a rapid and convenient method and gives higher accuracy than the estimation method. However, it involves a lot of interpolation work.

Note:

Arithmetical Calculation is considered more accurate than a graphical method, as the graphical method assumes only linear variation between the two guide points.

Principle of Leveling:

1. Simple leveling:

It is the simplest operation in leveling when it is required to find the difference in elevation between two points both of which are visible from a single position of the level.

2. Differential leveling:

This method is used in order to find out the difference in elevation between two points.

If they too apart.

If the difference in elevation between them is too great.

In such cases, it is necessary to set up the level in several positions and work in various stages. The method of simple leveling is employed in each of the successive stages. The process is also known as compound continues leveling.

If m = 2 × j – 3 ⇒ Stable Frame/Perfect Frame/Ideal Frame

If m < 2="" ×="" j="" –="" 3="" ⇒="" unstable="" frame/imperfect="">

If m > 2 × j – 3 ⇒ Over stiff frame/Redundant Frame

In general, surface tension decreases when temperature increases because cohesive forces decrease with an increase of molecular thermal activity. The influence of the surrounding environment is due to the adhesive action of liquid molecules that they have at the interface.

1. Cadastral Survey: To establish a boundary of properties for legal use.
2. City Survey: Survey of city
3. Topographical Survey: Surveys which are carried out to depict mountains, rivers, water bodies, wooded areas and other cultural details.
4. Guide Map Survey: For showing relief by contours and spot heights.

Approximately 97% of the world's water is saline.

This saline water is primarily found in the oceans, which cover a vast portion of the Earth's surface. Here are some key points regarding saline water:

• Saline water has a high concentration of salt, typically around 35 grams per litre.
• Only about 3% of the Earth's water is freshwater, which is essential for drinking and agriculture.
• Freshwater is found in rivers, lakes, glaciers, and underground aquifers.
• The distribution of freshwater is uneven, making access a global challenge.

Understanding the prevalence of saline water highlights the importance of conserving and protecting our freshwater resources.

I_Z=J=πD⁴/32

Polar moment of inertia of Hollow Cylinder:

I_Z = J = π(D4−d4)/32

The beam has internal hinges at C & D, so the beam can be break down as shown

In AC section moment applied = M

So the reaction will be = M/L/2 = 2/ML

The carry – over moment at B = 2M/L × L/4 = M/2

It is the soil which consists of roughly equal proportion of sand, silt, and clay. It is an ideal medium for the growth of the plants due to good moisture holding and infiltration capacity.

⇒ As sand, silt, and clay are not in equal proportion for the given sample, it is not a loamy soil.

Sandy Soil:

The soil in which a minimum of 35% constituents is sand and silt is less than 15% is said to be sandy soil.

⇒ As sand is only 20% for the above soil sample. It is not a sandy soil.

Silty Loam:

Soil composed of at least 70% of silt and clay and that too silt contributing to the highest fraction and with a minimum of 20% sand particles is termed as silty loam soil.

⇒ For the given sample, since major constituent is clay, given soil is clayey soil.

Shear resisted by concrete = τ_c bd

= 0.48 × 300 × 500 × 10 ^{- 3}

= 72 KN > 70 KN

Now, at the support shear to be resisted by bent up bar,

V_us = V_u - τ_c bd = 140 - 72 = 68 KN

Shear resisted by bent up bars near supports,

V_usb = 0.87 f_y A_st Sinα

V_usb = 0.87 × 415 × π/4 × 222 × sin45^∘

= 97 KN > 68 KN

So the beam is safe in shear throughout the beam with bent up bars.

No need of transverse shear reinforcement.

In sudden contraction, right after the sudden contraction  Ac , a vena contracta is formed; and then, right after, the flow widens again to fill the entire pipe. The region between the wall interior pipe and the vena contracta will be a region of separated flow.  The flow pattern after the vena contracta is similar to that after an abrupt enlargement and the loss is caused due to expansion of flow after sudden contraction.

Initial setting time of OPC is 30 minutes.

The final setting time of OPC is 10 hours.

Dk = 3J – R

Where,

J = No. of Joints = 2

R = External support reactions = 3

Dk = 3x2 – 3 = 3

n=1000/200=5

Unit weight of bars =7850kg/m³

Weight of bars

=(n+1)×π/4×(0.020)²×7580

Weight of bars

=6×π/4×(0.020)²×7580

= 14.80kg

Work is going on hence it is an activity.