Back to Years

Type:ALLMCQNATMSQ

General Aptitude(10)Mathematics Foundation(9)Environmental Chemistry(2)Environmental Microbiology(8)Water Resources and Environmental Hydraulics(8)Water & Wastewater Treatment and Management(5)Air and Noise Pollution(6)Solid and Hazardous Waste Management(6)Global and Regional Environmental Issues(3)Environmental Management and Sustainable Development(8)

General Aptitude

10 Questions

GATE→2023→General Aptitude→Verbal Ability

Q1

MCQ[1 Mark]

Rafi told Mary, "I am thinking of watching a film this weekend." The following reports the above statement in indirect speech: Rafi told Mary that he _____ of watching a film that weekend.

(A)

thought

(B)

is thinking

(C)

am thinking

(D)

was thinking

Explanation

GATE→2023→General Aptitude→Verbal Ability

Q2

MCQ[1 Mark]

Permit : _____ :: Enforce : Relax (By word meaning)

(A)

Allow

(B)

Forbid

(C)

License

(D)

Reinforce

Explanation

GATE→2023→General Aptitude→Quantitative Aptitude

Q3

MCQ[1 Mark]

Given a fair six-faced dice where the faces are labelled '1', '2', '3', '4', '5', and '6', what is the probability of getting a '1' on the first roll of the dice and a '4' on the second roll?

(A)

\frac{1}{36}

(B)

\frac{1}{6}

(C)

\frac{5}{6}

(D)

\frac{1}{3}

Explanation

GATE→2023→General Aptitude→Quantitative Aptitude

Q4

MCQ[1 Mark]

A recent survey shows that $65\%$ of tobacco users were advised to stop consuming tobacco. The survey also shows that 3 out of 10 tobacco users attempted to stop using tobacco. Based only on the information in the above passage, which one of the following options can be logically inferred with certainty?

(A)

A majority of tobacco users who were advised to stop consuming tobacco made an attempt to do so.

(B)

A majority of tobacco users who were advised to stop consuming tobacco did not attempt to do so.

(C)

Approximately 30% of tobacco users successfully stopped consuming tobacco.

(D)

Approximately 65% of tobacco users successfully stopped consuming tobacco.

Explanation

GATE→2023→General Aptitude→Quantitative Aptitude

Q5

MCQ[1 Mark]

How many triangles are present in the given figure?

(A)

12

(B)

16

(C)

20

(D)

24

Explanation

GATE→2023→General Aptitude→Verbal Ability

Q6

MCQ[2 Marks]

Students of all the departments of a college who have successfully completed the registration process are eligible to vote in the upcoming college elections. However, by the time the due date for registration was over, it was found that surprisingly none of the students from the Department of Human Sciences had completed the registration process. Based only on the information provided above, which one of the following sets of statement(s) can be logically inferred with certainty? (i) All those students who would not be eligible to vote in the college elections would certainly belong to the Department of Human Sciences. (ii) None of the students from departments other than Human Sciences failed to complete the registration process within the due time. (iii) All the eligible voters would certainly be students who are not from the Department of Human Sciences.

(A)

(i) and (ii)

(B)

(i) and (iii)

(C)

only (i)

(D)

only (iii)

Explanation

GATE→2023→General Aptitude→Quantitative Aptitude

Q7

MCQ[2 Marks]

Which one of the following options represents the given graph?

(A)

$f(x) = x^2 2^{-|x|}$

(B)

$f(x) = x 2^{-|x|}$

(C)

$f(x) = |x| 2^{-x}$

(D)

$f(x) = x 2^{-x}$

Explanation

GATE→2023→General Aptitude→Verbal Ability

Q8

MCQ[2 Marks]

Which one of the options does NOT describe the passage below or follow from it?

(A)

It is a reflection of why cancer seems so modern to most of us.

(B)

It tells us that modern cell biology uses and promotes metaphors of machinery.

(C)

Modern cell biology encourages metaphors of machinery, and cancer is often imagined as a machine.

(D)

Modern cell biology never uses figurative language, such as metaphors, to describe or explain anything.

Explanation

GATE→2023→General Aptitude→Quantitative Aptitude

Q9

MCQ[2 Marks]

The digit in the unit's place of the product $3^{999} \times 7^{1000}$ is

(A)

7

(B)

1

(C)

3

(D)

9

Explanation

GATE→2023→General Aptitude→Quantitative Aptitude

Q10

MCQ[2 Marks]

A square with sides of length $6\text{ cm}$ is given. The boundary of the shaded region is defined by two semi-circles whose diameters are the sides of the square, as shown. The area of the shaded region is _____ $\text{cm}^2$.

(A)

$9\pi$

(B)

18

(C)

20

(D)

$18\pi$

Explanation

Mathematics Foundation

9 Questions

GATE→2023→Mathematics Foundation→Calculus

Q11

MCQ[1 Mark]

Given are two ordinary differential equations: $P: \frac{dy}{dx} + x = x \sin y$ $Q: \frac{dy}{dx} + xy = e^xy$ The correct choice is

(A)

P is linear; Q is nonlinear

(B)

P is nonlinear; Q is linear

(C)

Both P and Q are linear

(D)

Both P and Q are nonlinear

Explanation

GATE→2023→Mathematics Foundation→Linear Algebra

Q12

MCQ[1 Mark]

P and Q are square matrices. Consider the following: $X: (P^{-1})^{-1} = P$ $Y: \text{Symmetric if } Q = -Q^T$ The correct choice is

(A)

X is TRUE; Y is FALSE

(B)

X is FALSE; Y is TRUE

(C)

Both X and Y are TRUE

(D)

Both X and Y are FALSE

Explanation

GATE→2023→Mathematics Foundation→Calculus

Q13

MCQ[1 Mark]

Given are two infinite series: $P: \sum \frac{n^2 + 1}{n^2}$ $Q: \sum \left(1 + \frac{1}{n}\right)^{-n}$ The correct choice is

(A)

P is convergent series; Q is divergent series

(B)

P is divergent series; Q is convergent series

(C)

Both P and Q are convergent series

(D)

Both P and Q are divergent series

Explanation

GATE→2023→Mathematics Foundation→Probability and Statistics

Q14

NAT[1 Mark]

A researcher compiled the following information about the performance of a kit in an outbreak: - Disease (probability = $0.002$), Positive response given disease = $0.98$ - No Disease (probability = $0.998$), Positive response given no disease = $0.03$ The probability of detecting an infection for a positive result through the kit would be _____ (rounded off to three decimal places).

Explanation

GATE→2023→Mathematics Foundation→Calculus

Q15

NAT[1 Mark]

The value of $\frac{4}{\pi} \int_{0}^{\pi/2} \sin^2 x \ dx$ is _____ (rounded off to two decimal places).

Explanation

GATE→2023→Mathematics Foundation→Probability and Statistics

Q16

MCQ[2 Marks]

$W_1, W_2, \dots, W_9$ represent the holding times of 9 water samples, which follow a normal distribution with mean $\mu = 8.33$ and standard deviation $S = 4.472$. $M$ represents the sample mean value of holding times. Assuming $Z$ has a standard normal distribution, select the correct statement which describes the expression for calculating the value of type 1 error where null hypothesis $H_0: \mu = 0$ and alternate hypothesis $H_a: M \le 6$.

(A)

P\{Z < (-1.565)\}

(B)

P\{Z < 1.565\}

(C)

P\{Z > (-1.565)\}

(D)

P\{Z > 1.565\}

Explanation

GATE→2023→Mathematics Foundation→Calculus

Q17

NAT[2 Marks]

Second order ordinary differential equation $\frac{d^2y}{dx^2} - \frac{dy}{dx} - 2y = 0$ has values $y = 2$ and $\frac{dy}{dx} = 1$ at $x = 0$. The value of $y$ at $x = 1$ is _____ (rounded off to three decimal places).

Explanation

GATE→2023→Mathematics Foundation→Linear Algebra

Q18

NAT[2 Marks]

Consider two matrices $P = \begin{bmatrix} 2 & 3 \\ 1 & 4 \end{bmatrix}$ and $Q = \begin{bmatrix} 5 & 4 \\ 0 & 2 \end{bmatrix}$. If $R = (PQ)^T$ then $\det R$ is _____ (in integer).

Explanation

GATE→2023→Mathematics Foundation→Calculus

Q19

NAT[2 Marks]

For the function $f(x) = x \sqrt{4 - x^2}$, the maximum value in the range $-2 \le x \le 2$ is _____ (rounded off to two decimal places).

Explanation

Environmental Chemistry

2 Questions

GATE→2023→Environmental Chemistry→Principles of Water Chemistry

Q20

MCQ[2 Marks]

Read the following statements regarding chromium: I. Trivalent chromium has relatively low aqueous solubility, and low mobility in the soil environment. By contrast, hexavalent chromium has a higher aqueous solubility and greater mobility in the soil environment. II. The chemical reaction between trivalent chromium and zero-valent iron will result in transformed version called hexavalent chromium. III. Hexavalent chromium is a known carcinogen. IV. Trivalent chromium has relatively higher human toxicity as compared to hexavalent chromium. The correct choice is

(A)

IV is correct; I and III are incorrect

(B)

II is correct; I and IV are incorrect

(C)

I and III are correct; II and IV are incorrect

(D)

I, II and IV are correct; III is incorrect

Explanation

GATE→2023→Environmental Chemistry→Principles of Water Chemistry

Q21

NAT[2 Marks]

The solubility of gas A is $16\text{ mg/L}$ in water and its vapor pressure is $0.042\text{ atm}$ at $25^\circ\text{C}$. In a closed system, the gas phase concentration of A is $10^{-3}\text{ mol/L}$. Assuming Ideal gas constant ($R$) value as $0.0821\text{ L-atm/mol-K}$, the concentration of gas A in water at $25^\circ\text{C}$ is _____ (in mg/L, rounded off to two decimal places).

Explanation

Environmental Microbiology

8 Questions

GATE→2023→Environmental Microbiology→Prokaryotic and Eukaryotic Microorganisms

Q22

MCQ[1 Mark]

Read the following statements: I. Photosynthesis takes place within the chloroplasts of the eukaryotes, whereas the breakdown of complex molecules to yield energy takes place in the cytoplasm and in the mitochondria. II. Photosynthesis takes place within the chloroplasts of the prokaryotes, whereas the breakdown of complex molecules to yield energy takes place in the cytoplasm and in the mitochondria. III. All living organisms retain the enzymatic machinery to partially oxidise glucose without the help of oxygen. This breakdown of glucose to pyruvic acid is called glycolysis. IV. ... The correct choice is

(A)

I and III are correct

(B)

II and IV are correct

(C)

I is correct whereas III is incorrect

(D)

II is correct whereas IV is incorrect

Explanation

GATE→2023→Environmental Microbiology→Microbial Metabolism

Q23

MCQ[1 Mark]

Read the following statements: i. Aerobic heterotrophic bacteria uses organic matter for carbon source and energy source. ii. Aerobic heterotrophic bacteria uses carbon dioxide for carbon source and energy source. in. Aerobic autotrophic bacteria uses carbon dioxide for carbon source and reduced substances for energy source. iv. Aerobic autotrophic bacteria uses organic matter for getting energy. The correct choice is

(A)

(i) is correct; (iii) is correct

(B)

(iv) is correct; (i) is incorrect

(C)

(i) is correct; (iv) is correct

(D)

(ii) is correct; (iv) is incorrect

Explanation

GATE→2023→Environmental Microbiology→Microbial Metabolism

Q24

MCQ[1 Mark]

A student wants to decide electron acceptor for aerobic, facultative and anaerobic bacteria. In this context, read the following statements: i. Dissolved Oxygen (DO) can act as electron acceptor for aerobic bacteria. ii. Nitrite can act as electron acceptor for aerobic bacteria. iii. Dissolved Oxygen (DO) can act as electron acceptor for anaerobic bacteria. iv. Nitrite can act as electron acceptor for facultative bacteria. The correct choice is

(A)

(i) is correct; (iv) is correct

(B)

(ii) is correct; (iii) is incorrect

(C)

(ii) is correct; (iii) is correct

(D)

(i) is correct; (ii) is correct

Explanation

GATE→2023→Environmental Microbiology→Microbial Metabolism

Q25

NAT[1 Mark]

The ratio of the moles of $CO_2$ evolved to the moles of $O_2$ consumed in respiration also called the respiratory quotient, is calculated for a carbohydrate ($C_6H_{12}O_6$) as substrate and found to be 1. Under similar conditions, for a fatty acid ($C_{51}H_{98}O_6$) as substrate, the respiratory quotient is _____ (rounded off to two decimal place).

Explanation

GATE→2023→Environmental Microbiology→Prokaryotic and Eukaryotic Microorganisms

Q26

MCQ[2 Marks]

Which one of the following statements is NOT correct?

(A)

Photophosphorylation is the synthesis of ATP from ADP and inorganic phosphate in the presence of light.

(B)

The process through which ATP is synthesised by cells (in mitochondria and chloroplasts) is called phosphorylation.

(C)

The Calvin cycle (carboxylation, reduction, and regeneration) occurs in all photosynthetic plants (C3, C4 or any other).

(D)

C3 plants have a special type of leaf anatomy, they tolerate higher temperatures, they show a response to high light intensities, have high rate of photosynthesis and reduced rate of photorespiration as compared to C4 plants.

Explanation

GATE→2023→Environmental Microbiology→Prokaryotic and Eukaryotic Microorganisms

Q27

MCQ[2 Marks]

Read the following statements: I. Bacteriophage is an anaerobic bacterium. II. Male-specific bacteriophage infect via the pili of other microorganisms including viruses. III. Bacteriophage is found in human as well as in animal excreta. IV. Bacteriophage can not indicate the presence of bacteria. The correct choice is

(A)

(I), (III) and (IV) are correct

(B)

(IV) is correct; (III) is incorrect

(C)

Both (III) and (IV) are incorrect

(D)

Both (III) and (IV) are correct

Explanation

GATE→2023→Environmental Microbiology→Microbial Metabolism

Q28

MCQ[2 Marks]

Read the following statements: i. In endogenous metabolism by aerobic bacteria, electron acceptor is present inside the cells. ii. In endogenous metabolism by aerobic bacteria, electron acceptor is dissolved oxygen. iii. The endogenous metabolism is linked to fermentative metabolism. iv. In exogenous metabolism by aerobic bacteria, enzyme mediated electron transfer happens within the cells. The correct choice is

(A)

(i) is correct; (iii) is correct

(B)

(ii) is correct; (iii) is incorrect

(C)

(iii) is incorrect; (iv) is incorrect

(D)

(iii) is correct; (iv) is correct

Explanation

GATE→2023→Environmental Microbiology→Microbial Metabolism

Q29

NAT[2 Marks]

A biological reactor is getting wastewater containing $1\text{ mole/L}$ acetate ions as carbon source. The following reaction takes place in the bio-reactor: $0.125 CH_3COO^- + 0.0295 NH_4^+ + 0.103 O_2 \rightarrow 0.0295 C_5H_7O_2N + 0.0955 H_2O + 0.095 HCO_3^- + 0.007 CO_2$ Given that $1\text{ g}$ acetate exerts $1.07\text{ g COD}$; $1\text{ mole}$ bacteria $= 113\text{ g VSS}$; $1\text{ mole}$ acetate ion $= 59\text{ g}$. Value of observed yield is _____ (in $\text{g VSS/g COD}$, rounded off to two decimal places).

Explanation

Water Resources and Environmental Hydraulics

8 Questions

GATE→2023→Water Resources and Environmental Hydraulics→Groundwater Resources

Q30

MCQ[1 Mark]

The kinematic viscosity of glycerin and kerosene are $1.2$ times and $0.95$ times of that of water, respectively. Glycerin and kerosene flow through two identical porous media having same hydraulic gradient. Assuming Darcy's law is valid for the porous media, the ratio of flow rate of kerosene to that of glycerin is

(A)

1.052

(B)

1.140

(C)

0.792

(D)

1.263

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q31

NAT[1 Mark]

The critical depth in a $2\text{ m}$ wide rectangular channel carrying a discharge of $10\text{ m}^3/\text{s}$ and taking value of acceleration due to gravity ($g$) as $9.81\text{ m/s}^2$ is _____ (in m, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Surface Water Resources

Q32

NAT[1 Mark]

An S-hydrograph was prepared for a catchment of $240\text{ km}^2$ using 3-hour unit hydrograph ($1\text{ cm}$ rainfall excess). The equilibrium discharge for the S-hydrograph would be _____ (in $\text{m}^3/\text{s}$, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Surface Water Resources

Q33

NAT[2 Marks]

The following figure shows a catchment ($Q, S, U, T, Q$) and adjoining raingauge stations $P, Q, R, S, U$ and $V$. Due to a storm, $20\text{ mm}, 25\text{ mm}, 30\text{ mm}, 15\text{ mm}, 22\text{ mm}$ and $18\text{ mm}$ rainfall depths were recorded by raingauges at $P, Q, R, S, U$ and $V$, respectively. The corresponding mean rainfall over the catchment using Thiessen polygon method is _____ (in mm, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q34

NAT[2 Marks]

A trapezoidal canal lined with cement concrete ($n = 0.01$) is designed to carry a discharge of $20\text{ m}^3/\text{s}$ at a bed slope $1$ in $400$. If the bed width is twice of the depth of flow and side slope of the canal section is $2$ ($1$ vertical : $2$ horizontal) then the corresponding depth of flow will be _____ (in m, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q35

NAT[2 Marks]

A plunger weighing $314\text{ kN}$ is balanced in a cylindrical vessel of diameter $1.5\text{ m}$ and filled with an oil (specific gravity $0.9$). If a pressure gauge is connected with the vessel using $1.5\text{ cm}$ diameter tube, the reading of the gauge will be _____ (in kPa, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Groundwater Resources

Q36

NAT[2 Marks]

A fully penetrating well is installed in a homogenous and isotropic confined aquifer. The aquifer has uniform thickness of $16\text{ m}$ and hydraulic conductivity of $25\text{ m/d}$. Water is being pumped out from the well at a constant rate of $0.1\text{ m}^3/\text{s}$ till steady state condition is reached. If a drawdown of $3.5\text{ m}$ is observed at a distance of $75\text{ m}$ from the well then the drawdown at a distance of $150\text{ m}$ from the well will be _____ (in m, rounded off to two decimal places).

Explanation

GATE→2023→Water Resources and Environmental Hydraulics→Environmental Hydraulics

Q37

NAT[2 Marks]

A pipeline is designed to deliver $20\text{ L/s}$ of an oil (kinematic viscosity $= 6 \times 10^{-6}\text{ m}^2/\text{s}$ and specific gravity $= 0.9$) under the laminar flow condition. The minimum diameter of the pipe will be _____ (in m, rounded off to two decimal places).

Explanation

Water & Wastewater Treatment and Management

5 Questions

GATE→2023→Water & Wastewater Treatment and Management→Water and Wastewater Quality Parameters & River Pollution

Q38

MCQ[1 Mark]

For testing alkalinity for a water sample, first phenolphthalein indicator is added. The water remains colorless. However, when a few drops of methyl orange is added to the sample, the color turns yellow. As per these observations, the correct choice is

(A)

Absence of $CO_3^{2-}$ and/or $HCO_3^-$ but the presence of $OH^-$ ions in the sample

(B)

Presence of $CO_3^{2-}$ and/or $HCO_3^-$ but the absence of $OH^-$ ions in the sample

(C)

Absence of $CO_3^{2-}$, $HCO_3^-$ and $OH^-$ ions in the sample

(D)

Presence of $CO_3^{2-}$, $HCO_3^-$ and $OH^-$ ions in the sample

Explanation

GATE→2023→Water & Wastewater Treatment and Management→Water Treatment Methods & Distribution

Q39

NAT[1 Mark]

River water containing two types of spherical suspended particles (clay particles, metal particles) is retained in a sedimentation tank. The clay particles having diameter of $75\text{ }\mu\text{m}$ and specific gravity of $2.65$ is settling in the tank with a constant velocity. The velocity of clay particles is 2 times of that of metal particles having specific gravity of $8$. Assume discrete settling and laminar flow conditions within the sedimentation tank. The estimated diameter of the metal particles is _____ (in $\mu\text{m}$ rounded off to integer).

Explanation

GATE→2023→Water & Wastewater Treatment and Management→Water Treatment Methods & Distribution

Q40

NAT[2 Marks]

A flask ($100\text{ ml}$ volume) has wastewater, which has $0.12\text{ mg/L}$ geosmin. Activated carbon is added in this flask for adsorbing geosmin as per the Freundlich isotherm model ($Q = 2.6 \times C^{0.73}$ where $Q$ is mg adsorbate/mg adsorbent and $C$ is the equilibrium concentration in $\text{mg/L}$). Activated carbon to be added in this flask for getting final remaining geosmin concentration of $0.05\text{ mg/L}$ would be _____ (in mg/L rounded off to three decimal places).

Explanation

GATE→2023→Water & Wastewater Treatment and Management→Water and Wastewater Quality Parameters & River Pollution

Q41

NAT[2 Marks]

You are doing an experiment to find out $BOD_5$ of a wastewater. You have taken $25\text{ mL}$ wastewater having ultimate BOD of $75\text{ mg/L}$ and placed it in $300\text{ mL}$ BOD bottle and filled it with dilution water. The initial DO of the diluted sample is $6.5\text{ mg/L}$. On the $7^{\text{th}}$ day, the DO is found to be $1.25\text{ mg/L}$. The $BOD_5$ of the wastewater sample is _____ (in mg/L, rounded off to two decimal places).

Explanation

GATE→2023→Water & Wastewater Treatment and Management→Kinetics and Reactor Design

Q42

NAT[2 Marks]

An aeration tank needs to be installed for the removal of VOC from water, where the required rate of flow of water through the aeration tank is $180,000\text{ m}^3/\text{d}$. Permissible limit of VOC in the water is $12\text{ }\mu\text{g/L}$. The saturation concentration of VOC is $5\text{ }\mu\text{g/L}$ and gas transfer rate constant is $0.40\text{ per second}$ at $25^\circ\text{C}$. The initial concentration of VOC in the water is $33\text{ }\mu\text{g/L}$. The volume of the aeration tank to satisfy the permissible limit of VOC at $25^\circ\text{C}$ is _____ (in $\text{m}^3$, rounded off to two decimal places).

Explanation

Air and Noise Pollution

6 Questions

GATE→2023→Air and Noise Pollution→Atmospheric Processes and Air Quality Parameters

Q43

MCQ[1 Mark]

Which of the following is true according to the Central Pollution Control Board (CPCB), Government of India's notification issued in the year 2009?

(A)

24 hour averaged standard for $PM_{2.5}$ in ambient air is $60\text{ }\mu\text{g/m}^3$; 24 hour averaged standard for $PM_{10}$ in ambient air is $100\text{ }\mu\text{g/m}^3$

(B)

24 hour averaged standard for $PM_{2.5}$ in indoor air is $60\text{ }\mu\text{g/m}^3$; 24 hour averaged standard for $PM_{10}$ in ambient air is $100\text{ }\mu\text{g/m}^3$

(C)

24 hour averaged standard for $PM_{2.5}$ in ambient air is $60\text{ }\mu\text{g/m}^3$; 24 hour averaged standard for $PM_{10}$ in indoor air is $100\text{ }\mu\text{g/m}^3$

(D)

24 hour averaged standard for $PM_{2.5}$ in indoor air is $60\text{ }\mu\text{g/m}^3$; 24 hour averaged standard for $PM_{10}$ in indoor air is $100\text{ }\mu\text{g/m}^3$

Explanation

GATE→2023→Air and Noise Pollution→Atmospheric Processes and Air Quality Parameters

Q44

MCQ[1 Mark]

The sub index values of $NO_2$, $SO_2$ and $PM_{10}$ are 80, 80 and 100, respectively. According to the National Air Quality Index (NAQI) released by the Government of India in the year 2015, the overall NAQI is

(A)

80

(B)

260

(C)

100

(D)

151

Explanation

GATE→2023→Air and Noise Pollution→Particulate Pollutants: Measurement and Control

Q45

MCQ[2 Marks]

A boiler in an industry, located where high plume rise is expected, releases flue gas with fine particulate matter. Which one of the following options is most suited and efficient if this particulate matter is intended for reuse?

(A)

reduce stack height and increase stack diameter

(B)

use of wet collectors

(C)

use of flue gas desulfurization (FGD)

(D)

use of electrostatic precipitator (ESP)

Explanation

GATE→2023→Air and Noise Pollution→Atmospheric Processes and Air Quality Parameters

Q46

MCQ[2 Marks]

Match the following: - J) Dalton's law -> (ii) Pressure exerted by a mixture of gases - K) Fick's law -> (i) Diffusion - L) Henry's law -> (iv) Gas-liquid phase transfer - M) Stoke's law -> (iii) Gravitational settling Select the correct option.

(A)

J-ii; K-i; L-iv; M-iii

(B)

J-iii; K-ii; L-i; M-iv

(C)

J-ii; K-iii; L-iv; M-i

(D)

J-i; K-iv; L-ii; M-iii

Explanation

GATE→2023→Air and Noise Pollution→Atmospheric Processes and Air Quality Parameters

Q47

NAT[2 Marks]

In a $30\text{ m}^3$ room, a stove in operation consumes wood at the rate of $0.25\text{ kg/h}$. The inflow and outflow rate of air in the room is the same, i.e. $500\text{ m}^3/\text{h}$. This stove emits a VOC species at a rate of $0.2\text{ g/kg}$ wood. The VOC species gets converted to $CO_2$ at a rate of $0.4\text{ per hour}$. Given: (i) the air in the room is completely mixed, (ii) initial concentration of the VOC species in the room is negligible, and (iii) concentration of the VOC species in the air entering the room is negligible. The concentration of the VOC species due to two hours of stove operation in the room is _____ (in $\mu\text{g/m}^3$, rounded off to one decimal place).

Explanation

GATE→2023→Air and Noise Pollution→Air Quality Management and Dispersion Modelling

Q48

NAT[2 Marks]

An industry with an effective stack height of $80\text{ m}$ emits $1200\text{ g/h}$ of $CO$. The windrose plotted using the meteorological data at the top of the stack, and the relation between dispersion coefficients and wind direction are given below: (Wind speed = $3\text{ m/s}$; Northeast wind frequency = $20\%$, highest frequency direction). Dispersion coefficients for Northeast: $\sigma_y = 50\text{ m}$, $\sigma_z = 20\text{ m}$. During the maximum duration of the year, the ground level concentration at the downwind distance of $2\text{ km}$ (at the plume centerline) from the stack is _____ (in $\mu\text{g/m}^3$, rounded off to two decimal places).

Explanation

Solid and Hazardous Waste Management

6 Questions

GATE→2023→Solid and Hazardous Waste Management→Biomedical, Plastic, C&D, E-Waste & Energy Sector Waste

Q49

MCQ[1 Mark]

Which of the following is NOT a designated waste category under Bio-medical Waste Management Rules, 2016 of Government of India?

(A)

Yellow

(B)

Green

(C)

Red

(D)

Blue

Explanation

GATE→2023→Solid and Hazardous Waste Management→Hazardous Waste Management and Soil Contamination

Q50

MCQ[1 Mark]

Consider the following waste categories: i) Domestic Hazardous Waste ii) Nuclear Waste iii) Sludge from wet scrubbers of hazardous waste treatment processes iv) Chromium bearing residue and sludge from leather tanneries Which one of the options correctly represents the waste categories NOT covered under Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016 of Government of India?

(A)

(i) and (ii) only

(B)

(i) and (iii) only

(C)

(ii) and (iv) only

(D)

(i), (ii) and (iii) only

Explanation

GATE→2023→Solid and Hazardous Waste Management→Biomedical, Plastic, C&D, E-Waste & Energy Sector Waste

Q51

MCQ[1 Mark]

Match the following: **Plastic Type** P. High-density polyethylene (HDPE) Q. Low-density polyethylene (LDPE) R. Polyethylene terephthalate (PET) S. Polystyrene (PS) **Common applications** (i) Garbage bags, bubble packaging (ii) Pharmaceutical bottles, Styrofoam cups (iii) Water bottles (iv) Geomembrane for landfill liner

(A)

P-(iv), Q-(i), R-(iii), S-(ii)

(B)

P-(i), Q-(iii), R-(ii), S-(iv)

(C)

P-(iv), Q-(ii), R-(i), S-(iii)

(D)

P-(ii), Q-(iii), R-(iv), S-(i)

Explanation

GATE→2023→Solid and Hazardous Waste Management→Integrated Solid Waste Management & Municipal Waste

Q52

MSQ[2 Marks]

Read the following statements about aerobic composting of organic fraction of municipal solid waste: I. The majority of the odour problem in an aerobic composting process is due to the development of anaerobic conditions within the compost pile. II. All organic carbon present in the waste will completely biodegrade in 14 days. III. At high C/N ratio, ammonia would be released and biological activity may also be impeded. IV. Optimum moisture content for aerobic composting process would be $50-60\%$. Lower moisture would slow down the biological process. Excessive moisture will make it difficult to maintain aerobic conditions. The correct choice(s) is/are

(A)

I and IV are correct

(B)

II and III are incorrect

(C)

I is correct; IV is incorrect

(D)

II is correct; IV is incorrect

Explanation

GATE→2023→Solid and Hazardous Waste Management→Integrated Solid Waste Management & Municipal Waste

Q53

NAT[2 Marks]

A city generates on average $1000\text{ metric tonnes/day}$ of municipal solid waste and follows integrated waste management system. $15\%$ of the total waste is recycled, $40\%$ of the total waste is used to produce compost. $25\%$ of the total waste is converted to refuse derived fuel (RDF) with $80\%$ efficiency. Remaining is disposed of in a sanitary landfill. The calorific value of the RDF is $15\text{ MJ/kg}$, which is further used to generate electricity. The electrical energy that could be generated from the RDF with a thermal to electrical energy conversion efficiency of $20\%$ is _____ (in MWh/d, rounded off to two decimal places).

Explanation

GATE→2023→Solid and Hazardous Waste Management→Integrated Solid Waste Management & Municipal Waste

Q54

NAT[2 Marks]

Ultimate analysis of a municipal solid waste sample is given below: - Carbon: $48\%$ - Hydrogen: $6\%$ - Oxygen: $35\%$ - Nitrogen: $6\%$ - Ash: $5\%$ For $1\text{ kg}$ of the municipal solid waste burnt, assuming that air contains only nitrogen and oxygen, maximum $CO_2$ emitted is _____ (in kg, rounded off to three decimal places).

Explanation

Global and Regional Environmental Issues

3 Questions

GATE→2023→Global and Regional Environmental Issues→Global Effects of Air Pollution & Climate Change

Q55

MCQ[1 Mark]

The correct ascending order of the following greenhouse gases with respect to their global warming potential relative to $CO_2$ in the time horizon of 100 years is

(A)

$CH_4 < N_2O < CFCl_3 < CF_2Cl_2$

(B)

$CF_2Cl_2 < CH_4 < N_2O < CFCl_3$

(C)

$CH_4 < N_2O < CF_2Cl_2 < CFCl_3$

(D)

$N_2O < CFCl_3 < CH_4 < CF_2Cl_2$

Explanation

GATE→2023→Global and Regional Environmental Issues→Ecology, Biodiversity & Population Growth

Q56

MCQ[2 Marks]

Read the following statements: I. According to the Liebig's law of minimum, the growth is regulated by the limited factors i.e., resources in scarcity and not by the resources in abundance. II. Shelford's law of tolerance states that, only the factors present in excess/abundance can affect the growth, development of an organism or rate of biological process. III. Shelford's law of tolerance states that, an organism's success is based on a complex set of conditions and that each organism has a certain minimum, maximum, and optimum levels of environmental factor or combination of factors that determine success. The correct choice is

(A)

I and II are correct; III is incorrect

(B)

I and III are correct; II is incorrect

(C)

II is correct; I and III are incorrect

(D)

III is correct; I and II are incorrect

Explanation

GATE→2023→Global and Regional Environmental Issues→Global Effects of Air Pollution & Climate Change

Q57

MSQ[2 Marks]

Which of the following statements is/are NOT true?

(A)

Urban heat island effect in a city can be reduced by increasing trees and vegetation cover in the city.

(B)

Urban heat island intensity is affected by $PM_{2.5}$ concentrations in a city.

(C)

Urban heat island intensity increases due to installation of reflective roofs in a city.

(D)

In comparison with the non-urban areas, urban heat island effect raises night-time temperatures more than daytime temperatures in cities.

Explanation

Environmental Management and Sustainable Development

8 Questions

GATE→2023→Environmental Management and Sustainable Development→Environmental Law, Policy, and Treaties

Q58

MCQ[1 Mark]

Place the following international conventions/conferences/protocols/declarations in the chronological order (oldest to latest) of their happening: i) United Nations conference in Stockholm which resulted in the establishment of UNEP (1972) il) Vienna convention for the protection of the Ozone layer (1985) iii) United Nations climate change conference in Glasgow commonly referred as COP26 (2021) iv) Montreal protocol on phasing out production of substances related to Ozone layer depletion (1987)

(A)

i, ii, iv, iii

(B)

i, ii, iii, iv

(C)

ii, iv, i, iii

(D)

iv, iii, ii, i

Explanation

GATE→2023→Environmental Management and Sustainable Development→Environmental Law, Policy, and Treaties

Q59

MCQ[1 Mark]

Read the following statements with reference to the Kyoto Protocol on Climate Change: i) Each signatory (country) has common and equal responsibility. ii) Clean development mechanism (CDM), joint implementation (JI) and international emission trading are the three mechanisms under Kyoto Protocol to reduce the greenhouse gas emissions. iii) Under Kyoto Protocol, India has agreed to reduce its greenhouse gas emissions by half by 2050 as compared to 2005 emissions. Which one of the following is correct choice?

(A)

only i) is TRUE

(B)

only ii) is TRUE

(C)

only i) and ii) are TRUE

(D)

only ii) and iii) are TRUE

Explanation

GATE→2023→Environmental Management and Sustainable Development→Environmental Law, Policy, and Treaties

Q60

MCQ[1 Mark]

Read the following statements: I. In environmental laws, the polluter pays principle is enacted to make the polluter responsible for paying for the damage done to the natural environment. II. The precautionary principle emphasizes caution, pausing and review before going for an innovation that may prove disastrous. III. The precautionary principle is often used by policy makers in situations where there is the possibility of harm from making a certain decision and conclusive evidence is not yet available. The correct choice is

(A)

I is correct; II and III are incorrect

(B)

I, II and III are correct

(C)

I and III are correct; II is incorrect

(D)

I and II are correct; III is incorrect

Explanation

GATE→2023→Environmental Management and Sustainable Development→Environmental Management Systems & Impact Assessment

Q61

MCQ[1 Mark]

Read the following statements: I. The goal of Life Cycle Analysis (LCA) is to assess the environmental impact of products from a system perspective and to identify possible improvement strategies. II. Environmental Impact Assessment (EIA) is defined as a process of identifying, predicting, and evaluating the likely impacts of a proposed project or development to define mitigation actions... The correct choice is

(A)

I is correct; II is incorrect

(B)

II is correct; I is incorrect

(C)

Both I and II are correct

(D)

Both I and II are incorrect

Explanation

GATE→2023→Environmental Management and Sustainable Development→Environmental Law, Policy, and Treaties

Q62

MCQ[1 Mark]

For the following major Indian environmental acts: i) Environmental Protection Act (1986) ii) Water Act (Prevention and Control of Pollution) (1974) iii) Air Act (Prevention and Control of Pollution) (1981) iv) The National Green Tribunal Act (2010) the correct chronological order (oldest to latest of their enactment) is

(A)

i), ii), iii), iv)

(B)

ii), i), iii), iv)

(C)

iii), i), iv), ii)

(D)

ii), iii), i), iv)

Explanation

GATE→2023→Environmental Management and Sustainable Development→Environmental Management Systems & Impact Assessment

Q63

MSQ[2 Marks]

Products P and Q have life cycle phases of material extraction, production, use, and end of life disposal. $CH_4$, $CO_2$ emissions and mass used per functional unit (f.u.) from the different phases of the products are given in the tables. Using global warming potential of $CH_4$ equal to $23\text{ kg of } CO_2\text{ per kg of } CH_4$, which of the following statement(s) is/are true?

(A)

Greenhouse gas emissions (kg $CO_2$ equivalent/f.u.) from the 'Material extraction' phase of product P is higher than that of product Q.

(B)

Greenhouse gas emissions (kg $CO_2$ equivalent/f.u.) from the 'Production phase' of product Q is higher than that of product P.

(C)

Greenhouse gas emissions (kg $CO_2$ equivalent/f.u.) from the 'End of life disposal' is higher for product Q than that of product P.

(D)

Greenhouse gas emissions (kg $CO_2$ equivalent/f.u.) from the 'complete life cycle' of the product P is higher than that of product Q.

Explanation

GATE→2023→Environmental Management and Sustainable Development→Energy and Environment

Q64

NAT[2 Marks]

Ms. Anita uses a BS-IV two wheeler petrol scooter, with a mileage of $50\text{ km/L}$, to travel $30\text{ km}$ every day. She exchanges this two wheeler with an electric scooter, which consumes electricity at $0.1\text{ kWh/10 km}$. Assuming the cost of petrol and electricity are fixed at Rs. $90\text{ per L}$ and Rs. $3.5\text{ per kWh}$, respectively, and maintenance cost is negligible, the operational cost saved in a year by Ms. Anita is _____ (in Rs., in integer).

Explanation

GATE→2023→Environmental Management and Sustainable Development→Environmental Management Systems & Impact Assessment

Q65

NAT[2 Marks]

An adult of $65\text{ kg}$ weight and life span of $65\text{ years}$ drinks water for $5\text{ years}$, which is contaminated with toluene of concentration $0.15\text{ mg/L}$. For toluene, reference dose is $0.200\text{ mg/kg-d}$. The person drinks $2\text{ L}$ of water per day. The hazard quotient from the toluene exposure for the adult will be _____ (rounded off to three decimal places).

Explanation