Civil Engineering
GATE CE purpose:exam-prep PYQs
Build your understanding with focused practice from past exam papers.
Questions 1161–1170 of 1300. Imported answers require independent review unless marked reviewed.
Question 51
Open questionCENAT2 marksNeeds review
A water sample analysis data is given below.
Ion | Concentration, mg/L | Atomic Weight |
|---|---|---|
Ca²⁺ | 60 | 40 |
Mg²⁺ | 30 | 24.31 |
HCO₃⁻ | 400 | 61 |
The carbonate hardness (expressed as mg/L of CaCO₃, up to one decimal place) for the water sample is _____
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Open questionCENAT2 marksNeeds review
At a small water treatment plant which has 4 filters, the rates of filtration and backwashing are 200 m
/d/m
and 1000 m
/d/m
, respectively. Backwashing is done for 15 min per day. The maturation, which occurs initially as the filter is put back into service after cleaning, takes 30 min. It is proposed to recover the water being wasted during backwashing and maturation. The percentage increase in the filtered water produced (up to two decimal places) would be _____Log in to check the answer
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Open questionCENAT2 marksNeeds review
The ultimate BOD (
) of a wastewater sample is estimated as 87% of COD. The COD of this wastewater is 300 mg/L. Considering first order BOD reaction rate constant k (use natural log) = 0.23 per day and temperature coefficient
= 1.047, the BOD value (in mg/L, up to one decimal place) after three days of incubation at 27°C for this wastewater will be _____Log in to check the answer
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Open questionCENAT2 marksNeeds review
A schematic flow diagram of a completely mixed biological reactor with provision for recycling of solids is shown in the figure.
S₀, S = readily biodegradable soluble BOD, mg/L
Q, Qᵣ, Qw = flow rates, m
/d
X₀, X, Xₑ, Xᵤ = microorganism concentrations (mixed-liquor volatile suspended solids or MLSS), mg/LThe mean cell residence time (in days, up to one decimal place) is _____
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Open questionCENAT2 marksNeeds review
A waste activated sludge (WAS) is to be blend with green waste (GW). The carbon (C) and nitrogen (N) contents, per kg of WAS and GW, on dry basis are given in the table.
Parameter | WAS | GW |
|---|---|---|
Carbon (g) | 54 | 360 |
Nitrogen (g) | 10 | 6 |
The ratio of WAS to GW required (up to two decimal places) to achieve a blend C:N ratio of 20:1 on dry basis _____
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Open questionCENAT2 marksNeeds review
The space mean speed (kmph) and density (vehicles/km) of a traffic stream are linearly related. The free flow speed and jam density are 80 kmph and 100 vehicles/km respectively. The traffic flow (in vehicles/h, up to one decimal place) corresponding to a speed of 40 kmph is _____
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Given the following data: design life n = 15 years, lane distribution factor D = 0.75, annual rate of growth of commercial vehicles r = 6%, vehicle damage factor F = 4 and initial traffic in the year of completion of construction = 3000 Commercial Vehicles Per Day (CVPD). As per IRC:37-2012, the design in terms of cumulative number of standard axles (in million standard axles, up to two decimal places) is _____
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A 7.5 m wide two-lane road on a plain terrain is to be laid along a horizontal curve of radius 510 m. For a design speed of 100 kmph, super-elevation is provided as per IRC: 73-1980. Consider acceleration due to gravity as 9.81 m/s
. The level difference between the inner and outer edges of the road (in m, up to three decimal places) is _____Log in to check the answer
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Open questionCENAT2 marksNeeds review
An aircraft approaches the threshold of a runway strip at a speed of 200 km/h. The pilot decelerates the aircraft at a rate of 1.697 m/s
and takes 18 s to exit the runway strip. If the deceleration after exiting the runway is 1 m/s
, then the distance (in m, up to one decimal place) of the gate position from the location of exit on the runway is _____Log in to check the answer
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Open questionCENAT2 marksNeeds review
An aerial photograph of a terrain having an average elevation of 1400 m is taken at a scale of 1:7500. The focal length of the camera is 15 cm. The altitude of the flight above mean sea level (in m, up to one decimal place) is _____
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