Most answered questions in Environmental Engineering / GO Civil

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1

GATE2017 CE-1: 55
The wastewater having an organic concentration of $54$ mg/l is flowing at a steady rate of $0.8 \: m^3/day$ through a detention tank of dimensions $2m \times 4 m \times 2 m$. If the contents of the tank are well mixed and the decay constant $0.1$ per day, the outlet concentration (in mg/l, up to one decimal place) is _________

The wastewater having an organic concentration of $54$ mg/l is flowing at a steady rate of $0.8 \: m^3/day$ through a detention tank of dimensions $2m \times 4 m \times 2...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

1 answer

2

GATE2018 CE-2: 51
At a small water treatment plant which has $4$ filters, the rates of filteration and backwashing are $200 \: m^3/d/m^2$ and $1000 m^3/d/m^2$, respectively. Backwashing is done for $15$ min per day. The maturation, which ... the water being wasted during backwashing and maturation. The percentage increase in the filtered water produced (up to two decimal places) would be ______

At a small water treatment plant which has $4$ filters, the rates of filteration and backwashing are $200 \: m^3/d/m^2$ and $1000 m^3/d/m^2$, respectively. Backwashing is...

gatecse

4.0k points

gatecse asked Feb 17, 2018

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1 answer

3

GATE2018 CE-2: 14
As per $\text{IS }10500:2012$, for drinking water in the absence of alternate source of water, the permissible limits for chloride and sulphate, in mg/L, respectively are $250$ and 200$ $1000$ and 400$ $200$ and 250$ $500$ and 1000$

As per $\text{IS }10500:2012$, for drinking water in the absence of alternate source of water, the permissible limits for chloride and sulphate, in mg/L, respectively are...

gatecse

4.0k points

gatecse asked Feb 17, 2018

0 votes

1 answer

4

GATE2018 CE-1: 51
A water sample analysis data is given below, ... $CaCO_3$, up to one decimal place), for the water sample, is ____

A water sample analysis data is given below,$$\begin{array}{|c|c|} \hline \textbf{Ion} & \textbf{Concentration, mg/L} & \textbf{Atomic Weight} \\ \hline Ca^{2+} & 60 & 40...

gatecse

4.0k points

gatecse asked Feb 17, 2018

0 votes

1 answer

5

GATE2018 CE-1: 52
The ultimate BOD $(L_0)$ 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) $= 0.23$ ... value in (in mg/L, up to one decimal place) after three days of incubation at $27^{\circ}$C for this wastewater will be _____

The ultimate BOD $(L_0)$ 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 consta...

gatecse

4.0k points

gatecse asked Feb 17, 2018

0 votes

1 answer

6

GATE2018 CE-1: 53
A waste activated sludge (WAS) is to be blended 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. ... $C: N$ ratio of $20:1$ on dey basis is ____

A waste activated sludge (WAS) is to be blended 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...

gatecse

4.0k points

gatecse asked Feb 17, 2018

0 votes

1 answer

7

GATE2018 CE-1: 33
A rapid sand filter comprising a number of filter beds is required to produce $99$ MLD of potable water. Consider water loss during backwashing as $5\%$, rate of filtration as 6.0 m/h and length to width ratio of filter bed as $1.35$. The width of each ... to take care of break-down, repair, and maintenance. The total number of filter beds required will be $19$ $20$ $21$ $22$

A rapid sand filter comprising a number of filter beds is required to produce $99$ MLD of potable water. Consider water loss during backwashing as $5\%$, rate of filtrati...

gatecse

4.0k points

gatecse asked Feb 17, 2018

0 votes

1 answer

8

GATE2018 CE-1: 25
A city generates $40 \times 10^6$ kg of municipal solid waste (MSW) per year, out of which only $10\%$ is recovered/recycled and the rest goes to landfill. The landfill has a single life of $3$ m height and is compacted to a density of $550 \: kg/m^3$. If $80 \%$ of the landfill is assumed to be MSW, the landfill area (in $m^2$, up to one decimal place) required would be _______

A city generates $40 \times 10^6$ kg of municipal solid waste (MSW) per year, out of which only $10\%$ is recovered/recycled and the rest goes to landfill. The landfill h...

gatecse

4.0k points

gatecse asked Feb 17, 2018

1 votes

0 answers

9

Made Easy Gate Previous year Questions
If we have 3 samples Initial DO. Final DO. Volume 1. 9.2 6.9 5 2. 9.1 4.4 10 3. 8.4 0 50 Do we need to consider last sample for finding average BOD?

If we have 3 samples Initial DO. Final DO. Volume1. 9.2 6.9 52. 9.1 4.4 ...

Don6

130 points

Don6 asked May 11, 2021

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0 answers

10

GATE Civil 2021 Set 2 | Question: 14
Determine the correctness or otherwise of the following Assertion $\text{[a]}$ and the Reason $\text{[r]}$. $\text{Assertion [a]}$: One of the best ways to reduce the amount of solid wastes is to reduce the consumption of raw materials. $\text{Reason [r]}$: Solid ... Both $\text{[a]}$ and $\text{[r]}$ are false $\text{[a]}$ is true but $\text{[r]}$ is false

Determine the correctness or otherwise of the following Assertion $\text{[a]}$ and the Reason $\text{[r]}$.$\text{Assertion [a]}$: One of the best ways to reduce the amou...

go_editor

5.3k points

go_editor asked Mar 1, 2021

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0 answers

11

GATE Civil 2021 Set 2 | Question: 15
The hardness of a water sample is measured directly by titration with $\text{0.01 M}$ solution of ethylenediamine tetraacetic acid $\text{(EDTA)}$ using eriochrome black $\text{T (EBT)}$ as an indicator. The $\text{EBT}$ reacts ... colour of the solution changes from blue-green to reddish brown blue to colourless reddish brown to pinkish yellow Wine red to blue

The hardness of a water sample is measured directly by titration with $\text{0.01 M}$ solution of ethylenediamine tetraacetic acid $\text{(EDTA)}$ using eriochrome black ...

go_editor

5.3k points

go_editor asked Mar 1, 2021

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0 answers

12

GATE Civil 2021 Set 2 | Question: 17
Which of the following statement$\text{(s)}$ is/are correct? Increased levels of carbon monoxide in the indoor environment result in the formation of carboxyhemoglobin and the long term exposure becomes a cause of cardiovascular diseases ... in the indoor environment will result in the formation of photochemical smog which is a cause of cardiovascular diseases

Which of the following statement$\text{(s)}$ is/are correct?Increased levels of carbon monoxide in the indoor environment result in the formation of carboxyhemoglobin and...

go_editor

5.3k points

go_editor asked Mar 1, 2021

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0 answers

13

GATE Civil 2021 Set 2 | Question: 32
Read the statements given below. Value of the wind profile exponent for the 'very unstable' atmosphere is smaller than the wind profile exponent for the 'neutral' atmosphere. Downwind concentration of air pollutants due to an elevated point source will be ... is False and $\text{iii}$ is False $\text{iii}$ is False and $\text{iv}$ is False

Read the statements given below.Value of the wind profile exponent for the 'very unstable' atmosphere is smaller than the wind profile exponent for the 'neutral' atmosphe...

go_editor

5.3k points

go_editor asked Mar 1, 2021

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0 answers

14

GATE Civil 2021 Set 2 | Question: 51
An activated sludge process $\text{(ASP)}$ is designed for secondary treatment of $7500\:m^{3}/$day of municipal wastewater. After primary clarifier, the ultimate $\text{BOD}$ of the influent, which enters into $\text{ASP}$ ... underflow volume (in $m^{3}$/day, $\textit{round off to one decimal place}$) of sludge wastage is _______________________

An activated sludge process $\text{(ASP)}$ is designed for secondary treatment of $7500\:m^{3}/$day of municipal wastewater. After primary clarifier, the ultimate $\text{...

go_editor

5.3k points

go_editor asked Mar 1, 2021

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0 answers

15

GATE Civil 2021 Set 2 | Question: 52
A grit chamber of rectangular cross-section is to be designed to remove particles with diameter of $\text{0.25 mm}$ and specific gravity of $2.70$. The terminal settling velocity of the particles is estimated as $\text{2.5 cm/s}$. The ... the chamber (in $\text{m}, \textit{in integer}$) to remove $\text{0.25 mm}$ particles completely is ____________________

A grit chamber of rectangular cross-section is to be designed to remove particles with diameter of $\text{0.25 mm}$ and specific gravity of $2.70$. The terminal settling ...

go_editor

5.3k points

go_editor asked Mar 1, 2021

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16

GATE Civil 2021 Set 1 | Question: 11
Which one of the following statements is correct? Pyrolysis is an endothermic process, which takes place in the absence of oxygen Pyrolysis is an exothermic process, which takes place in the absence of oxygen Combustion is an endothermic ... takes place in the abundance of oxygen Combustion is an exothermic process, which takes place in the absence of oxygen

Which one of the following statements is correct?Pyrolysis is an endothermic process, which takes place in the absence of oxygenPyrolysis is an exothermic process, which ...

Arjun

13.0k points

Arjun asked Feb 19, 2021

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0 answers

17

GATE Civil 2021 Set 1 | Question: 12
Which one of the following is correct? The partially treated effluent from a food processing industry, containing high concentration of biodegradable organics, is being discharged into a flowing river at a point $\text{P}$. If the rate of ... $1$ A young lake characterized by low nutrient content and low plant productivity is called $\textit{eutrophic lake}$

Which one of the following is correct?The partially treated effluent from a food processing industry, containing high concentration of biodegradable organics, is being di...

Arjun

13.0k points

Arjun asked Feb 19, 2021

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0 answers

18

GATE Civil 2021 Set 1 | Question: 13
The liquid forms of particulate air pollutants are dust and mist mist and spray smoke and spray fly ash and fumes

The liquid forms of particulate air pollutants aredust and mistmist and spraysmoke and sprayfly ash and fumes

Arjun

13.0k points

Arjun asked Feb 19, 2021

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0 answers

19

GATE Civil 2021 Set 1 | Question: 28
A $50$ $\text{mL}$ sample of industrial wastewater is taken into a silica crucible. The empty weight of the crucible is $54.352$ $\text{g}$. The crucible with the sample is dried in a hot air oven at $104\;^{\circ}C$ till a constant weight of ... volatile solids is _____________________ $\text{15540 mg/L}$ $\text{8620 mg/L}$ $\text{6920 mg/L}$ $\text{1700 mg/L}$

A $50$ $\text{mL}$ sample of industrial wastewater is taken into a silica crucible. The empty weight of the crucible is $54.352$ $\text{g}$. The crucible with the sample ...

Arjun

13.0k points

Arjun asked Feb 19, 2021

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0 answers

20

GATE Civil 2021 Set 1 | Question: 33
A water sample is analyzed for coliform organisms by the multiple-tube fermentation method. The results of confirmed test are as follows: $\begin{array}{|cl|cI|cI|}\hline &\textbf{Sample size $ ... $110$ The $\text{MPN}$ of coliform organisms per $\text{100 mL}$ is $1100000$ $110000$ $1100$ $110$

A water sample is analyzed for coliform organisms by the multiple-tube fermentation method. The results of confirmed test are as follows:$\begin{array}{|cl|cI|cI|}\hline&...

Arjun

13.0k points

Arjun asked Feb 19, 2021

0 votes

0 answers

21

GATE Civil 2021 Set 1 | Question: 34
Ammonia nitrogen is present in a given wastewater sample as the ammonium ion $\text({NH}_{4}$^{+})$ and ammonia $\text({NH}_{3})$. If $ ... _{3}$ will be found in equal measures At $\text{pH}$ $7.0$, $\text{NH}_{4}$^{+}$ will be predominant

Ammonia nitrogen is present in a given wastewater sample as the ammonium ion $\text({NH}_{4}$$^{+})$ and ammonia $\text({NH}_{3})$. If $\text{pH}$ is the only deciding fa...

Arjun

13.0k points

Arjun asked Feb 19, 2021

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0 answers

22

GATE Civil 2021 Set 1 | Question: 51
A baghouse filter has to treat $12\text{ m}^3/\text{s}$ of waste gas continuously. The baghouse is to be divided into $5$ ... $5 \text{ m}$ in length. The total number of bags ($\textit{in integer}$) required in the baghouse is __________________

A baghouse filter has to treat $12\text{ m}^3/\text{s}$ of waste gas continuously. The baghouse is to be divided into $5$ sections of equal cloth area such that one secti...

Arjun

13.0k points

Arjun asked Feb 19, 2021

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0 answers

23

GATE Civil 2021 Set 1 | Question: 52
A secondary clarifier handles a total flow of $9600 \text{ m}^3\text{/d}$ from the aeration tank of a conventional activated-sludge treatment system. The concentration of solids in the flow from the aeration tank is $3000\text{ mg/L}$. ... . The surface area of the designed clarifier for thickening (in $\text{m}^2$, $\textit{in integer}$) is ___________________

A secondary clarifier handles a total flow of $9600 \text{ m}^3\text{/d}$ from the aeration tank of a conventional activated-sludge treatment system. The concentration of...

Arjun

13.0k points

Arjun asked Feb 19, 2021

0 votes

0 answers

24

GATE2020-CE-1-25
A river has a flow of $1000$ million litres per day (MLD), $BOD_5$ of $5\:mg/litre$ and Dissolved Oxygen (DO) level of $8\:mg/litre$ before receiving the wastewater discharge at a location. For the existing environmental conditions, the saturation ... complete mixing of wastewater and river water, the immediate DO deficit (in $mg/litre$ round off to two decimal places), is ______.

A river has a flow of $1000$ million litres per day (MLD), $BOD_5$ of $5\:mg/litre$ and Dissolved Oxygen (DO) level of $8\:mg/litre$ before receiving the wastewater disch...

go_editor

5.3k points

go_editor asked Feb 27, 2020

0 votes

0 answers

25

GATE2020-CE-1-53
A gaseous chemical has a concentration of $41.6\:\mu mol/m^3$ in air at $1$ atm pressure and temperature $293\:K$. The universal gas constant $R$ is $82.05\times10^{-6}\;(m^3\:atm)/(mol\:K)$. Assuming that ideal gas law is valid , the concentration of the gaseous chemical (in ppm, round off to one decimal place), is ______.

A gaseous chemical has a concentration of $41.6\:\mu mol/m^3$ in air at $1$ atm pressure and temperature $293\:K$. The universal gas constant $R$ is $82.05\times10^{-6}\;...

go_editor

5.3k points

go_editor asked Feb 27, 2020

0 votes

0 answers

26

GATE2020-CE-1-54
A stream with a flow rate of $5\:m^3/s$ is having an ultimate BOD of $30\:mg/litre$. A wastewater discharge of $0.20\:m^3/s$ having $BOD_5\:\text{of}\:500\:mg/litre$ joins the stream at a location and instantaneously gets mixed up completely. The ... $e$). The BOD (in mg/litre, round off to two decimal places) remaining at $3\:km$ downstream from the mixing location, is __________

A stream with a flow rate of $5\:m^3/s$ is having an ultimate BOD of $30\:mg/litre$. A wastewater discharge of $0.20\:m^3/s$ having $BOD_5\:\text{of}\:500\:mg/litre$ join...

go_editor

5.3k points

go_editor asked Feb 27, 2020

0 votes

0 answers

27

GATE2020 CE-2-16
The relationship between oxygen consumption and equivalent biodegradable organic removal (i.e.,BOD) in a closed container with respect to time is shown in the figure Assume that the rate of oxygen consumption is directly proportional to the amount of degradable organic matter and is expressed as ... is $BOD_5 = L_5$ $BOD_t = L_0-L_t$ $L_0 = L_te^{-kt}$ $L_t = L_0(1-e^{-kt})$

The relationship between oxygen consumption and equivalent biodegradable organic removal (i.e.,BOD) in a closed container with respect to time is shown in the figureAssum...

go_editor

5.3k points

go_editor asked Feb 13, 2020

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0 answers

28

GATE2020 CE-2-17
A gas contains two types of suspended particles having average sizes of $2\: \mu m$ and $50\: \mu m$. Amongst the options given below, the most suitable pollution control strategy for removal of these ... bag filter electrostatic precipitator followed by venturi scrubber electrostatic precipitator followed by cyclonic separator bag filter followed by electrostatic precipitator

A gas contains two types of suspended particles having average sizes of $2\: \mu m$ and $50\: \mu m$. Amongst the options given below, the most suitable pollution control...

go_editor

5.3k points

go_editor asked Feb 13, 2020

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0 answers

29

GATE2020 CE-2-52
The ion product of water $(pK_w)$ is $14$. If a rain water sample has a $pH$ of $5.6$, the concentration of $OH^-$ in the sample (in $10^{-9}\: \text{mol/litre}$, round off to one decimal place), is ________.

The ion product of water $(pK_w)$ is $14$. If a rain water sample has a $pH$ of $5.6$, the concentration of $OH^-$ in the sample (in $10^{-9}\: \text{mol/litre}$, round o...

go_editor

5.3k points

go_editor asked Feb 13, 2020

0 votes

0 answers

30

GATE2020 CE-2-53
A waste to energy plant burns dry solid waste of composition: Carbon $= 35\%$, Oxygen $= 26\%$ , Hydrogen $= 10\%$, Sulphur $= 6\%$, Nitrogen $= 3\%$ and Inerts $= 20\%.$ Burning rate is $1000\: $ tonnes/d. Oxygen in air ... The stoichiometric (theoretical) amount of air ( in tonnes/d, round off to the nearest integer) required for complete burning of this waste is ________.

A waste to energy plant burns dry solid waste of composition: Carbon $= 35\%$, Oxygen $= 26\%$ , Hydrogen $= 10\%$, Sulphur $= 6\%$, Nitrogen $= 3\%$ and Inerts $= 20\%.$...

go_editor

5.3k points

go_editor asked Feb 13, 2020

0 votes

0 answers

31

GATE2020 CE-2-54
A sample of water contains an organic compound $C_8H_{16}O_8$ at a concentration of $10^{-3}\: \text{mol/litre}$. Given that the atomic weight of $C = 12\: \text{g/mol}, H = 1\: \text{g/mol}$, and $O = 16\: \text{g/mol}$, the theoretical oxygen demand of water (in $g$ of $O_2$ per litre, round off to two decimal places), is ________.

A sample of water contains an organic compound $C_8H_{16}O_8$ at a concentration of $10^{-3}\: \text{mol/litre}$. Given that the atomic weight of $C = 12\: \text{g/mol}, ...

go_editor

5.3k points

go_editor asked Feb 13, 2020

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0 answers

32

GATE2017 CE-2-8
As per Noise Pollution (Regulation and Control) Rules $2000$ of India, the day time noise limit for a residential zone, expressed in dB(A)L$_{eq}$, is $55$ $65$ $75$ $85$

As per Noise Pollution (Regulation and Control) Rules $2000$ of India, the day time noise limit for a residential zone, expressed in dB(A)L$_{eq}$, is$55$$65$$75$$85$

gatecse

4.0k points

gatecse asked Aug 7, 2019

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0 answers

33

GATE2017 CE-2-9
Following observations have ben made for the elevation and temperature to ascertain the stability of the atmosphere: $\begin{array}{|c|c|} \hline \text{Elevation (in m) } & \text{Temperature (in }^{\circ} \text{C)} \\ \hline 10 & 15.5 \\ \hline 60 & 15.0 \\ \hline 130 & 14.3 \\ \hline \end{array}$ The atmosphere is classified as Stable Unstable Neutral Inverse

Following observations have ben made for the elevation and temperature to ascertain the stability of the atmosphere:$$\begin{array}{|c|c|} \hline \text{Elevation (in m) }...

gatecse

4.0k points

gatecse asked Aug 7, 2019

0 votes

0 answers

34

GATE2017 CE-2-10
The most important type of species involved in the degradation of organic matter in the case of activated sludge process is autotrophs heterotrophs prototrophs photo-autotrophs

The most important type of species involved in the degradation of organic matter in the case of activated sludge process isautotrophsheterotrophsprototrophsphoto-autotrop...

gatecse

4.0k points

gatecse asked Aug 7, 2019

0 votes

0 answers

35

GATE2017 CE-2-50
The composition of a municipal solid waste sample is given below: ... The difference between the energy content of the waste sample calculated on dry basis and as-discarded basis (in kJ/kg) would be _______

The composition of a municipal solid waste sample is given below:$\begin{array}{|l|c|c|c|} \hline \text{Component} & \text{Percent by} & \text{Moisture Content} & \text{E...

gatecse

4.0k points

gatecse asked Aug 7, 2019

0 votes

0 answers

36

GATE2017 CE-2-51
For a given water sample, the ratio between BOD$_{\text{5-day, 20}^{\circ} C}$ and the ultimate BOD is $0.68$. The value of the reaction rate constant $k$ (on base $e$) (in day$^{-1}$, up to two decimal places) is ________

For a given water sample, the ratio between BOD$_{\text{5-day, 20}^{\circ} C}$ and the ultimate BOD is $0.68$. The value of the reaction rate constant $k$ (on base $e$) (...

gatecse

4.0k points

gatecse asked Aug 7, 2019

0 votes

0 answers

37

GATE2017 CE-2-52
A municipal corporation is required to treat $1000 \: m^3/day$ of water. It is found that an overflow rate of $20 m/day$ will produce a satisfactory removal of the discrete suspended particles at a depth of $3 m$. The diameter (in meters, round to the nearest integer) of a circular settling tank designed for the removal of these particles would be ___________

A municipal corporation is required to treat $1000 \: m^3/day$ of water. It is found that an overflow rate of $20 m/day$ will produce a satisfactory removal of the discre...

gatecse

4.0k points

gatecse asked Aug 7, 2019

0 votes

0 answers

38

GATE2019 CE-1: 18
Which one of the following is a secondary pollutant? Ozone Carbon Monoxide Hydrocarbon Volatile Organic Carbon (VOC)

Which one of the following is a secondary pollutant?OzoneCarbon MonoxideHydrocarbonVolatile Organic Carbon (VOC)

Arjun

13.0k points

Arjun asked Feb 14, 2019

0 votes

0 answers

39

GATE2019 CE-1: 34
Sedimentation basin in a water treatment plant is designed for a flow rate of $0.2 \: m^3/s$. The basin is rectangular with a length of $32 \: m$, width of $8 \:m $, and depth of $4 \: m$. Assume that the settling velocity of these particles is governed by ... diameter $25 \mu m$ (spherical and uniform), the removal efficiency of these particles is $51 \%$ $65 \%$ $78 \%$ $100 \%$

Sedimentation basin in a water treatment plant is designed for a flow rate of $0.2 \: m^3/s$. The basin is rectangular with a length of $32 \: m$, width of $8 \:m $, and ...

Arjun

13.0k points

Arjun asked Feb 14, 2019

0 votes

0 answers

40

GATE2019 CE-1: 40
A sample of air analysed at $0^{\circ} C$ and $1 \: atm$ pressure is reported to contain $0.02 \: ppm$ (parts per million) of $NO_2$. Assume the gram molecular mass of $NO_2$ as $46$ and its volume at $0^{\circ} C$ and $1 \: atm$ pressure as $22.4$ litres per mole. The equivalent $NO_2$ concentration (in microgram per cubic meter, round off to $2$ decimal places) would be ________

A sample of air analysed at $0^{\circ} C$ and $1 \: atm$ pressure is reported to contain $0.02 \: ppm$ (parts per million) of $NO_2$. Assume the gram molecular mass of $N...

Arjun

13.0k points

Arjun asked Feb 14, 2019