GATE 2024 Environmental Science and Engineering Question Paper is available for download. The exam was successfully conducted by IISc/IITs on February 3 in the afternoon session from 2:30 PM to 5:30 PM. As per the student’s initial reactions, the GATE 2024 Environmental Science and Engineering Question Paper was reported as Moderate. The Environmental Chemistry and Microbiology section was reported as Moderate to Challenging, the Water Resources and Pollution Control section as Moderate, and the General Aptitude section as Easy to Moderate.

GATE 2024 Environmental Science and Engineering Question Paper with Answer Key PDF

Candidates can download the GATE 2024 Environmental Science and Engineering Question Paper with Answer Key PDFs using the link below.

GATE Environmental Science and Engineering 2024 Questions with Solutions

GENERAL APTITUDE

Question 1:

If ’→’ denotes increasing order of intensity, then the meaning of the words [sick → infirm → moribund] is analogous to [silly → → daft]. Which one of the given options is appropriate to fill the blank?

(1) frown
(2) fawn
(3) vein
(4) vain

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Question 2:

The 15 parts of the given figure are to be painted such that no two adjacent parts with shared boundaries (excluding corners) have the same color. The minimum number of colors required is:

(1) 4
(2) 3
(3) 5
(4) 6

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Question 3:

How many 4-digit positive integers divisible by 3 can be formed using only the digits {1, 3, 4, 6, 7}, such that no digit appears more than once in a number?

(1) 24
(2) 48
(3) 72
(4) 12

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Question 4:

The sum of the following infinite series is:
1/2 + 1/4 + 1/3 + 1/8 + 1/9 + 1/16 + 1/27 + . . .

(A) 11/3
(B) 7/2
(C) 13/4
(D) 9/2

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Question 5:

In an election, the share of valid votes received by the four candidates A, B, C, and D is represented by the pie chart shown. The total number of votes cast in the election were 1,15,000, out of which 5,000 were invalid. Based on the data provided, the total number of valid votes received by the candidates B and C is:

(1) 45, 000
(2) 49, 500
(3) 51, 750
(4) 54, 000

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Question 6:

Thousands of years ago, some people began dairy farming. This coincided with a number of mutations in a particular gene that resulted in these people developing the ability to digest dairy milk. Based on the given passage, which of the following can be inferred?

(1) All human beings can digest dairy milk.
(2) No human being can digest dairy milk.
(3) Digestion of dairy milk is essential for human beings.
(4) In human beings, digestion of dairy milk resulted from a mutated gene.

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Question 7:

The probability of a boy or a girl being born is 1/2. For a family having only three children, what is the probability of having two girls and one boy?

(1) 3/8
(2) 1/8
(3) 1/4
(4) 1/2

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Question 8:

Person 1 and Person 2 invest in three mutual funds A, B, and C. The amounts they invest in each of these mutual funds are given in the table. At the end of one year, the total amount that Person 1 gets is 500 more than Person 2. The annual rate of return for the mutual funds B and C is 15% each. What is the annual rate of return for the mutual fund A?

(1) 7.5%
(2) 10%
(3) 15%
(4) 20%

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Question 9:

Three different views of a dice are shown in the figure below. The piece of paper that can be folded to make this dice is:

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Question 10:

Visualize two identical right circular cones such that one is inverted over the other and they share a common circular base. If a cutting plane passes through the vertices of the assembled cones, what shape does the outer boundary of the resulting cross-section make?

(1) A rhombus
(2) A triangle
(3) An ellipse
(4) A hexagon

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Environmental Science and Engineering

Question 11:

Ten cards in a pack are numbered as 1, 2, 3, . . . , 10. The probability of drawing a card with an even number or a number which is a multiple of 5 from the pack is:

(1) 4/10
(2) 6/10
(3) 2/10
(4) 3/10

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Question 12:

Hardness in water is NOT caused by .

(1) Ca²⁺
(2) Sr²⁺
(3) Mg²⁺
(4) CO₃²⁻

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Question 13:

The maximum coordination number of Sn⁴⁺ is .

(1) 4
(2) 8
(3) 6
(4) 2

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Question 14:

Rod-shaped bacterial cells are called:

(1) Bacilli
(2) Cocci
(3) Spirilla
(4) Diplococci

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Question 15:

Tuberculosis is predominantly caused by:

(1) Entamoeba histolytica
(2) Salmonella typhi
(3) Mycobacterium bovis
(4) Bacillus cereus

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Question 16:

Which one of the following conversions belongs to nonsymbiotic nitrogen fixation?

(1) Atmospheric nitrogen to ammonia by Rhizobium bacteria in nodules attached to roots of legumes
(2) Atmospheric nitrogen to ammonia by Azotobacter species
(3) Nitrate to gaseous nitrogen under anaerobic conditions
(4) Nitrate to ammonia under aerobic conditions

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Question 17:

Crown corrosion of reinforced cement concrete sewer is caused by:

(1) Sulfur oxidizing bacteria
(2) Iron oxidizing bacteria
(3) Denitrifying bacteria
(4) Fermentative bacteria

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Question 18:

The processes of removal of particles in a rapid sand filter with their description is given in the table below:

Process Description
(i) Straining P: Removes only particles in the water large enough to get caught in the pores of the filter
(ii) Sedimentation Q: Larger and heavier particles do not follow the fluid streamline around the sand grain and settle on the grain
(iii) Interception R: Particles that do follow the streamline, but are too large and are caught because they brush up against the sand grains
(iv) Diffusion S: Very small particles are experiencing Brownian motion and may collide with the sand grains by chance

Select the correct match:

(1) i : S, ii : P, iii : Q, iv : R
(2) i : Q, ii : R, iii : S, iv : P
(3) i : R, ii : S, iii : P, iv : Q
(4) i : P, ii : Q, iii : R, iv : S

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Question 19:

The environmental temperature increases by 6 ◦C/km with height at a particular location. The stability condition of the atmosphere at the location is:

(1) Stable
(2) Unstable
(3) Inversion
(4) Neutral

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Question 20:

As per the United Nations agenda for sustainable development adopted in September 2015, the number of Sustainable Development Goals (SDGs) are and the proposed target year to achieve them is ?

(1) 15; 2035
(2) 17; 2030
(3) 20; 2050
(4) 18; 2047

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Question 21:

Which one of the following is NOT a greenhouse gas?

(1) CO₂
(2) CH₄
(3) H₂S
(4) H₂O

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Question 22:

As per the United Nations Environmental Program (UNEP) guidelines 2004, the maximum size of microplastics is:

(1) 10 mm
(2) 5 mm
(3) 10 μm
(4) 5 μm

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Question 23:

The costliest functional element in an urban centralized Municipal Solid Waste management infrastructure for a typical Indian Tier I city is:

(1) Biological treatment
(2) Collection and transport
(3) Disposal in a sanitary landfill
(4) Thermal treatment

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Question 24:

The eigenvalues of the matrix [4 3]
                                                    [3 4]

(1) 1
(2) 2
(3) 7
(4) 4

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Question 25:

If X is a vector, and A and B are linear operators, then the correct mathematical relationship(s) is/are:

(1) (A + B)X = AX + BX
(2) (λA)X = λ(AX)
(3) (AB)X = A(BX)
(4) (A + B)X = A^TX + B^TX

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Question 26:

In the context of fluid flow, which of the following statement(s) is/are correct?

(1) Streamline is a line, tangent to which at any point gives the direction of the velocity vector.
(2) Streakline is the actual path traversed by a given fluid particle in an unsteady flow.
(3) Streakline and streamline are same for a steady flow.
(4) Pathline and streamline are same for a steady flow.

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Question 27:

In a rectangular open channel, the flow is critical, and the flow depth is 2 m. Select the correct statement(s):

(1) Specific energy for the flow is 3.0 m
(2) Specific energy for the flow is 2.0 m
(3) Froude number is 1.0
(4) Froude number is 1.5

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Question 28:

With respect to particle settling in wastewater treatment systems, the correct statement(s) is/are:

(1) Settling in grit chamber and primary sedimentation tanks are examples of Type-I settling.
(2) Settling in primary sedimentation tank and secondary sedimentation tank are examples of Type-II settling.
(3) Settling in grit chamber is an example of Type-I settling, whereas settling in primary sedimentation tank is an example of Type-II settling.
(4) Settling in secondary sedimentation tank is an example of Type-III settling, whereas settling in primary sedimentation tank is an example of Type-II settling.

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Question 29:

The equipment that can be used to control particulate air pollution in an industrial unit is/are:

(1) Electrostatic precipitator
(2) Cyclone separator
(3) Gravity settler
(4) Incinerator

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Question 30:

Which is/are the secondary air pollutant(s)?

(1) O₃
(2) HNO₃
(3) CO₂
(4) H₂SO₄

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Question 31:

As per the Hazardous Waste (Management and Handling) Rules, 2016, of India, which is/are the characteristic(s) that must be exhibited by a waste to be classified as a “characteristic” hazardous waste?

(1) Ignitability
(2) Reactivity
(3) Radioactivity
(4) Toxicity

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Question 32:

The function f(x) = x³ − 4.5x² − 12x has a local maximum at x = (an integer value) in the range x = −2 to + 2.

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Question 33:

Consider the equation dy/dx = x² + e^x with y = 1 at x = 0. The value of y at x = 1 is (rounded off to 2 decimal places). Take the value of e (base of natural logarithm) as 2.7.

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Question 34:

A municipal solid waste digester generates 1000 kg of methane gas. The volume of the tank needed to store this gas at 30°C and 3 atmospheric pressure is liters (an integer value). Use R = 0.082 L·atm/mol·K, Atomic weights of C = 12, and H = 1.

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Question 35:

A Class-A pan was setup adjacent to a lake for measuring evaporation losses in the lake. The depth of water in the pan at the beginning of a certain week was 250 mm. In that week, there was a rainfall event with 10 mm depth. Water depth in the pan at the end of the week was 240 mm. The pan coefficient is 0.8. The estimated lake evaporation during the week was mm (an integer value).

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Question 36:

A population (with mean μ) follows normal distribution. Ten samples (N) are drawn at random with a mean value of x and standard deviation S. The table below provides the confidence limits C(t) of the cumulative probability function for Student’s t-distribution two-tailed test with degrees of freedom D. 
Which one of the following expressions is correct for testing the null hypothesis H0 : μ = 0 at 10% significance level?

(1) −1.81 < x / √S/(N−1) < 1.81
(2) −1.83 < x/ √S/(N−1) < 1.83
(3) −1.37 < x/√S/(N−1) < 1.37
(4) −2.23 < x/√S/(N−1) < 2.23

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Question 37:

Which one is the solution y(x) for the following ordinary differential equation and the specified boundary conditions?
d²y / dx² − 3 dy/dx + 2y = 2e^−2x , y(0) = 2, dy/dx|_x=0 = 1

(1) y(x) = 1/3 e^−2x − 2e^−x − 1/3 e^2x
(2) y(x) = 1/3 e^−2x + 2e^−x − 1/3 e^2x
(3) y(x) = 1/3 e^−2x + 2e^−x + 1/3 e^2x
(4) y(x) = 1/3 e^−2x − 2e^−x + 1/3 e^2x

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Question 38:

A saturated CaCO₃ stock solution is existing at 25°C. In one experiment (i) 25 g Na₂CO₃ is added to the stock solution. In another experiment (ii) 25 g Na₂SO₄ is added to the stock solution. Select the correct statement from the following:

(A) Addition of (i) increases the concentration of Ca²⁺ and addition of (ii) decreases the concentration of Ca²⁺.
(B) Addition of (i) decreases the concentration of Ca²⁺ and addition of (ii) increases the concentration of Ca²⁺.
(C) Addition of (i) and (ii) increase the concentration of Ca²⁺.
(D) Addition of (i) and (ii) decrease the concentration of Ca²⁺.

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Question 39:

Consider second-order kinetics (r_c = −kC²) under steady-state conditions. The ratio of volume of a complete mixed reactor (CMR) to that of a plug flow reactor (PFR) to achieve 90% reduction in the concentration is .Inlet concentrations in both the reactors are the same.

(1) 10.0
(2) 1.0
(3) 0.1
(4) 2.3

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Question 40:

Consider two horizontal layers of an aquifer as shown in the figure. Each layer is isotropic and homogeneous. Flow is parallel to the stratification. Thickness and horizontal hydraulic conductivity of layer-1 are h₁ and K₁, respectively. Thickness and horizontal hydraulic conductivity of layer-2 are h₂ and K₂, respectively, where h₁ is not equal to h₂. The equivalent horizontal conductivity K_x for the aquifer system is given by .

(1) K_x = (K₁h₁+K₂h₂) / (h₁+h₂)
(2) K_x = (K₁+K₂)/2
(3) K_x = (K₁h₂+K₂h₁) / (h₁+h₂)
(4) K_x = √K₁K₂

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Question 41:

A gravity settling chamber of height H and length L is designed to control particulate air pollution. In the chamber, the horizontal velocity of air flow is V_h and terminal settling velocity of the target particle is V_t. Which one of the following expressions is the correct concept used to calculate the minimum size of the target particle that will be removed with 100% efficiency?

(A) V_t /L = V_h / H
(B) V_h × V_t = L × H
(C) V_h = V_t × L × H
(D) V_t / H = V_h / L

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Question 42:

Consider the function f(x) = ln(sin(x)). Expand f(x + h) using Taylor’s series. In this context, the correct statement(s) is/are:

(A) Second term in the Taylor’s series i.e., the term which includes h: h · ln(sin(x))
(B) First term is ln(sin(x))
(C) Third term in the Taylor’s series i.e., the term which includes h²/2 is: − h²/2sin²(x)
(D) Third term in the Taylor’s series i.e., the term which includes h²/2 is: 2h²/sin³(x)

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Question 43:

Enzymes with the class of enzymes are listed in the table. Select the correct match(es) from the following:
(a) Lactate dehydrogenase (i) Isomerases
(b) Alanine racemase (ii) Transferases
(c) Lipase (iii) Oxidoreductases
(d) Hexokinase (iv) Hydrolases

(A) (a) - (iii); (b) - (i)
(B) (c) - (iv); (d) - (ii)
(C) (a) - (ii); (b) - (iv)
(D) (c) - (iii); (d) - (i)

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Question 44:

With reference to disinfection, which of the following statement(s) is/are CORRECT?

(A) Ethanol damages lipid structures in the bacterial cell membrane.
(B) Mercuric chloride inactivates cellular enzymes containing sulfhydryl groups.
(C) Glutaraldehyde inactivates protein.
(D) Isopropyl alcohol cannot be used as a disinfectant.

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Question 45:

Which of the following statement(s) is/are CORRECT?

(A) DNA is composed of nucleotides.
(B) Five types of nitrogenous bases occur in DNA.
(C) Each phosphate is attached to two deoxyribose units in a single strand of DNA.
(D) The ratio of adenine to guanine is always 1:1 in a double stranded DNA.

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Question 46:

The Streeter–Phelps oxygen sag equation for a river is based on a few assumptions. The correct assumption(s) is/are:

(1) At any instant the deoxygenation rate is directly proportional to the amount of oxidizable organic material present.
(2) At any instant the deoxygenation rate is inversely proportional to the amount of oxidizable organic material present.
(3) The reoxygenation rate is directly proportional to the dissolved oxygen deficit.
(4) The reoxygenation rate and deoxygenation rate are directly proportional to the saturation concentration of dissolved oxygen.

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Question 47:

Water is flowing FULL through a rectangular tunnel of size 3 m (width) × 2 m (height). The average velocity of flow is 1 m/s. The frictional head loss is observed to be 1 m per km. Consider acceleration due to gravity (g) as 10 m/s². The correct statement(s) is/are:

(1) Hydraulic radius is 0.6 m.
(2) Darcy–Weisbach friction factor is 0.048.
(3) Hydraulic radius is 2 m.
(4) Darcy–Weisbach friction factor is 0.024.

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Question 48:

Based on the ISO 14040 methodology for Life Cycle Assessment, match the terms with the descriptions in the table.

a) Goal and Scope (i) Definition of the reference unit
b) Functional Unit (ii) Definition of the scope of the study and level of detail
c) Life Cycle Inventory (iii) Assessment of environmental impacts
d) Impact Assessment (iv) Compiling of environmental data and methodological approaches

(A) (a)-(ii); (b)-(i)
(B) (a)-(iii); (b)-(i)
(C) (c)-(iii), (d)-(iv)
(D) (c)-(iv), (d)-(iii)

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Question 49:

Consider the equation for a curve, y = f(x) = x² + x. The area enclosed by the curve, the x-axis (y = 0 line), and the vertical lines passing through x = 1 and x = 2 is calculated as follows:

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Question 50:

The pH of a solution containing 0.1M of acetic acid and 0.05M of sodium acetate is (rounded off to 2 decimal places). The pK_a value of ionization of acetic acid is 4.76.

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Question 51:

The ionic strength of a solution containing 0.01M of CaCl₂ and 0.001M of Na₂SO₄ is M (rounded off to 3 decimal places).

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Question 52:

The concentration of Ozone corresponding to a mixing ratio of 120 ppbv at pressure of 1 atmosphere and temperature of 25°C is μg/m³ (rounded off to 1 decimal place). Atomic weight of oxygen = 16; R = 0.0821 L·atm/mol·K.

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Question 53:

One million liters per day (MLD) of wastewater with a soluble BOD of 200 mg/L is treated in an activated sludge process. The BOD of treated wastewater is 20 mg/L. The observed yield coefficient of the biological system is 0.35. The daily biomass generation in the system is kg (an integer value).

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Question 54:

An industry discharges 2 million liters per day (MLD) of wastewater with a temperature of 45°C and a pH of 2, whereas the neighboring industry produces 3 MLD of wastewater with a temperature of 30°C and pH of 8. If both the wastewaters are mixed and carried through a pipeline, then the resultant pH of mixed wastewater is (rounded off to 2 decimal places). Neglect buffering capacity of the system and the temperature effect on pH.

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Question 55:

Consider a watershed and isohyets as shown in the figure. The average rainfall in the watershed is mm (an integer value).

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Question 56:

With reference to the gate shown in the figure, the gate will start opening automatically when the water level ’h’ above the hinge is 3.40 m (rounded off to 2 decimal places).

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Question 57:

In a cyclone separator of radius 25 cm, a particle is traveling with a gas stream at a velocity of 18 m/s. The ratio of centrifugal force to the gravitational force acting on the particle is (rounded off to 2 decimal places). Consider acceleration due to gravity (g) as 9.8 m/s².

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Question 58:

Two sources of noise, adjacent to each other in a room, have sound pressure levels of 30 and 40 decibel (dB). The combined sound pressure level in the room is dB (rounded off to 2 decimal places). Use reference sound pressure as 20 μPa.

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Question 59:

An industrial stack emits 100 g/s of CO at an effective height of ’H’, where the wind speed is 5 m/s. At 3 km distance downwind, the values of dispersion coefficient in y-direction and z-direction are 50 m and 25 m, respectively. The CO concentration at the centerline of the plume at 3 km distance downwind is mg/m³ (rounded off to 2 decimal places).

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Question 60:

Two hypothetical organic waste streams A and B are mixed prior to the composting process. Waste-A has 2.16% of C and 1.20% of N. Waste-B has 19.10% of C and 0.14% of N. The quantity of Waste-B that should be mixed with per kg of Waste-A to achieve the desired C:N ratio of 25 is kg (rounded off to 2 decimal places).

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Question 61:

Food waste, paper waste and plastic waste have typical densities of 280 kg/m³, 80 kg/m³, and 50 kg/m³, respectively. The mixed waste is composed of 70% food waste, 20% paper waste, and 10% plastic waste. The density of the mixed waste is kg/m³ (rounded off to 2 decimal places). Assume both the waste streams are completely dry and percentages are volumetric contributions.

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Question 62:

For a biodegradable waste with a chemical formula C₅H₁₀O₂N, the maximum theoretical methane production per ton of waste is kg (rounded off to 2 decimal places). Assume 100% anaerobic conversion. Atomic weights of C: 12, H: 1, O: 16, N: 14.

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Question 63:

A person consumes 2.5 liters of water per day. The water quality test indicated that the supplied water has a Pb concentration of 0.6 mg/L. If the weight of the person is 75 kg, the exposure level for Pb for this person from this drinking water source is mg/kg/day (rounded off to 2 decimal places).

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Question 64:

In a region, total annual consumption of gasoline is 30.6 million tons. The land required for growing sugarcane to produce enough bioethanol to replace the gasoline completely is km² (an integer value).

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Question 65:

Initially a bottle contained 400 g of ethanol. Half of ethanol was used by a student for preparing the stock solution in an environmental chemistry laboratory just before summer vacation of 90 days. After completing the procedure, the student left the bottle uncorked. If the unsealed bottle loses ethanol at a rate of 0.5 g/day, the ethanol that will be left in the bottle at the end of the summer vacation is g (an integer value).