DRDO STA Computer Science Civil Tier 2 Mock Test- 4 Free Online Test 2026

1. For the main title: 6 mm × 6 mm to 12 mm × 12 mm

2. For subtitle and headings: 4 mm × 4 mm to 5 mm × 5 mm

3. Notes, dimensions, Construction Notes, etc: 2 mm × 2 mm to 4 mm × 4 mm

i) Lesser energy requirement

ii) lower nutrient requirement

iii) production of biogas which is a valuable source of energy

Anaerobic Decomposition:

Organic Impurities + Anaerobic Bacteria → CO₂ + CH₄ + Energy

Red: Indicates vehicle on the street towards which it is facing must stop.

Yellow: Indicates clearance time for the vehicle which have entered the intersection area by the end of green light.

Green: Indicates that the vehicle on the street towards which it is facing can proceed.

At certain depth, the fibers would have reached the strain of 0.002 and the stress of 0.446f_ck.

On further increasing the load, the strain will ultimately reach to the value of 0.0035.

Beyond this strain, the concrete is believed to fail. So, once the extreme fibers fail, the cracks will develop, which leads to the weakening of the section and leading to failure of the structure.

N = 2 R = 300 m

L = 6 m V = 80 km/hr

Extra width required on curves = NL² / 2R = 0.105V / √ R

= 2×6² / 2×300 = 0.105×80 / √ 300

= 0.605 say 0.6 m.

Gypsum controls the rate of hardening of the cement. During the manufacturing process, a small amount of gypsum during the final grinding process helps to control the setting time of cement.

Flash set of cement would lead to premature stiffening of cement and hence it is undesirable for construction work.

Gypsum is added to the cement after cooling of the clinkers in around 3 to 5%.

The most suitable option among all of the above is 2.5 to 3.5%

For equilibrium

fN ≥ mg sin θ

⇒ fmg cos θ ≥ mg sin θ

⇒ fcos θ ≥ sin θ

⇒ f ≥ tan θ 

⇒ f ≥ e

Deflection, δ = ∂U/∂F

In which beam deflection is higher, strain energy stored will be maximum.

In cantilever, the deflection will be highest.

The deflection of a simply supported beam is higher than propped cantilever as one of the support is fixed.

In a fixed beam, the deflection will be minimum.

So,

δ_cantilever >  δ_{simple-support} > δ_{propped cantilever} > δ_fixed

∴ U_fixed < U_{proped-cantilever} < U_{simple-support} < U_cantliver 

Prandtl mixing length is zero at the pipe wall as the flow is laminar i.e. negligible velocity fluctuation at the boundary of the pipe wall.

The modular ratio m has the value of 280/3σ_cbc, where σ_cbc is the permissible compressive stress in concrete due to bending in N/mm².

= 1.44 + (7.32 – 1.44) e^-3.4t

= 1.44 + 5.88 e^-3.4t

Cumulative infiltration at the end of 2h

= ∫ [f(t) dt] from limit 0 to 2

= ∫ 1.44 + 5.88 e^-3.4t dt 0 to 2

= 1.44t – 5.88/3.4 e^-3.4t 0 to 2

= 1.44 × 2 – 5.88/3.4 × e^-3.4×2 + 5.88/3.4 × 1

= 4.607 cm

Variance,

where

t₀ = optimistic time

t_M = most likely time

t_P = pessimistic time

The probable range is from (t_E – 3σ) to (t_E + 3σ)

CaSO₄ is known as gypsum and is commonly used as retarder. Rest other compounds like Calcium Chloride, Sodium Chloride and Sodium Sulphate are used as accelerators.

Soda-lime glass having light transmission properties, as well as low melting temperature, which make it suitable for use as window glass.

Borosilicate Glass

Borosilicate glass is an engineered glass developed specifically for use in laboratories and applications where thermal, mechanical and chemical conditions are too harsh for standard, household-type soda lime glass.

Lead Glass:

Lead glass is a variety of glass in which lead replaces the calcium content of a typical potash glass. Lead Glass find their applications in ornaments, decanters, jewelry, optical lenses, enamels and lacquers, glass sealants and solders and radiation shielding from gamma and x-rays.

In the Straight line method, it is assumed that the property loses its value by the same amount every year. A fixed amount of the original cost is deducted every year so that at the end of the utility period, only the scrap value is left.

Annual Depreciation is given by:

D = C-S/n

Where,

D = Annual Depreciation

S = Scrap value

n = life of the property in years = 90 years

S = Scrap value = 0.1 × 50000 = ₹ 5000

C = Original cost = ₹ 50000

Calculation:

Book value of the property at the end of 20 years = Original cost - 20 × D.

∴ Book Value = 50000 – 20 × 500 = ₹ 40000/-

i) Aldural

ii) Aluminum bronze

iii) Duralumin

iv) Y-alloy

Important Points:

Bell metal, Speculum metal, and Gunmetal are alloys of Bronze.

Monel metal is an alloy of nickel

Dow metal and Electron metal is an alloy of Magnesium.

Minimum eccentricity equals to unsupported length of column/500 plus lateral dimension/30, subject to a minimum of 20 mm.

So eccentricity = 20 mm

Hence, number of bolts required = 360/60 = 6

Hence option D is right answer.

The percentage by weight of aggregate particles whose greatest dimension is greater than 1.8 times of their mean diameter is known as Elongation Index.

Two types of test apparatus may be used for conducting flash point tests on bitumen, namely the Pensky-Martens Closed Cup Tester and Open Cup Tester.

If the bituminous binder is further heated to a temperature higher than the flashpoint, the binder material itself catches fire and continues to burn, the lowest temperature causing this condition is called the "fire point.”

Fire Point: It is the lowest temperature at which application of a test flame causes the binder material to ignite and burn at least for five seconds under specified test conditions.

Note: The fire point is always higher than the flashpoint of a material.

Pensky-Martens Open Cup Tester is used to determine the fire point of the bituminous binders.

Free Ammonia – indicate recent pollution

Nitrate – indicate old pollution (fully oxidized)

Nitrite – indicate partly decomposed condition

Organic – indicate quantity of nitrogen before decomposition started.

Check Valve: These valves are used to check the flow of water in reverse direction. These are generally provided on the delivery side of the pump. These valves work automatically.

Scour valve: This valve is used to drain the water out of the pipe system.

The essence of the intersection control is to resolve these conflicts at the intersection for the safe and efficient movement of both vehicular traffic and pedestrians.

The safety within a roundabout and the efficiency of a roundabout can be increased respectively by decreasing the entry radius and increasing the exit radius.

Note:

There are two methods of intersection controls 

1) time sharing and

2) space sharing.

The type of intersection control that has to be adopted depends on the traffic volume, road geometry, cost involved, importance of the road etc.