GATE 2025 ES – Previous Year Questions with Solutions
All 65 questions of GATE 2025 ES with answers and explanations. Read each question, then practise it by topic or as a full paper.
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- Question 1 – Courage : Bravery :: Yearning : Select the most appropriate option to complete the analogy.
- Question 2 – We tennis in the lawn when it suddenly started to rain. Select the most appropriate option to complete the above sentence.
- Question 3 – A 4 × 4 digital image has pixel intensities (U) as shown in the figure. The number of pixels with U 4 is: 0 1 0 2 --- --- --- --- 4 7 3 3 5 5 4 4 6 7…
- Question 4 – In the given figure, the numbers associated with the rectangle, triangle, and ellipse are 1, 2, and 3, respectively. Which one among the given options…
- Question 5 – A rectangle has a length L and a width W, where L > W. If the width, W, is increased by 10%, which one of the following statements is correct for all…
- Question 6 – Column-I has statements made by Shanthala; and, Column-II has responses given by Kanishk. Column-I Column-II --- --- P. This house is in a mess. 1.…
- Question 7 – Weight of a person can be expressed as a function of their age. The function usually varies from person to person. Suppose this function is identical…
- Question 8 – A regular dodecagon (12-sided regular polygon) is inscribed in a circle of radius r cm as shown in the figure. The side of the dodecagon is d cm. All…
- Question 9 – If a real variable x satisfies 3x2 = 27 9x, then the value of 2x2(2x)2 is:
- Question 10 – The number of patients per shift (X) consulting Dr. Gita in her past 100 shifts is shown in the figure. If the amount she earns is ₹ 1000(X - 0.2),…
- Question 11 – For s> a ,find the Laplace transform of f(x)= ax.
- Question 12 – Find the general solution of d2y/dx2+4y=0.
- Question 13 – Classify P= n=11/n and Q= n=11/n2.
- Question 14 – Which reaction is a redox reaction?
- Question 15 – Which process is performed by autotrophic bacteria?
- Question 16 – For flood routing: P Hydrologic routing uses continuity and momentum equations. Q Hydraulic routing uses continuity and energy equations. Choose the…
- Question 17 – For gradually varied flow, P states y n>y c>y in an M3 profile; Q states y n<y c<y in an S1 profile. Here y n,y c,y are normal, critical and actual…
- Question 18 – Match reactor types 1 Plug flow,2 Continuously stirred tank,3 Batch with diagrams x, y, z. The stirrer symbol denotes mixing; diagrams are not to…
- Question 19 – In zero liquid discharge, a multiple-effect evaporator is commonly used for
- Question 20 – P:Under India’s 2009 NAAQS, the annual time-weighted PM 10 standard exceeds the PM 2.5 standard. Q:Under the National AQI released in 2015,the PM 10…
- Question 21 – Which components are most likely in the segregated combustible fraction of mixed municipal waste?
- Question 22 – Match i SDG6,ii SDG11,iii SDG3,iv SDG12 with p Good Health and Well-being, q Responsible Consumption and Production, r Sustainable Cities and…
- Question 23 – Which description applies to the Basel Convention?
- Question 24 – Consider (i) Pollutant concentrations are generally modeled as lognormal;(ii) concentrations are generally Poisson;(iii) weekly exceedance frequency…
- Question 25 – Select the correct statements on microorganism structure and reproduction.
- Question 26 – For nitrification:(i) acceptor type differs between Nitrosomonas and Nitrobacter;(ii) predominant carbon source is organic matter;(iii) predominant…
- Question 27 – A researcher uses a conventional Gaussian plume model to estimate New Delhi pollution caused by nearby-state stubble burning, which emits particles,…
- Question 28 – Which statements about plastic waste management are correct?
- Question 29 – Which displayed flowsheets correctly produce RDF from segregated dry waste collected in blue municipal-waste containers? Select all that apply.
- Question 30 – Which statements about lichens are correct?
- Question 31 – Methane hydrates trap methane in a water-crystal structure. Which statements are correct?
- Question 32 – Which statements about urban environments are correct?
- Question 33 – Which statements about cumulative toxicity are correct?
- Question 34 – Evaluate x0(1+x)/(2 x),to two decimal places.
- Question 35 – An unconfined aquifer covers 20 km×20 km, has conductivity 4 m/day, porosity .32,specific yield .18 and initial saturated thickness 30 m. Extract 4108…
- Question 36 – A researcher adds HgCl 2 to water at pH 10 and calculates expected mercury concentration from the added mass. An instrument measuring only free Hg2+…
- Question 37 – Label regions I–IV of the phosphoric-acid speciation diagram.
- Question 38 – For microbial metabolism:(i) carbon use for cell synthesis is anabolism;(ii) during catabolism ATP is converted to ADP. Choose the correct option.
- Question 39 – The ASP diagram labels flow Q, substrate S, microorganisms X, and aeration volume V. Subscripts 0,r, w, e, i denote influent, recycle, waste,…
- Question 40 – Consider:(i) sound pressure changes with distance from the source;(ii) sound power is a source property;(iii) sound intensity is sound power per unit…
- Question 41 – At 1 atm and 25°C, a pollutant concentration of 365 µg/m³ corresponds to 139 ppb. Atomic weights are C12,H1,O16,N14,S32. Which pollutant is the…
- Question 42 – Which gives the best dioxin/furan control for waste-incinerator flue gas?
- Question 43 – Which statements about water solubility are correct?
- Question 44 – Under substrate-unlimited conditions in Monod kinetics, which statements are correct?
- Question 45 – Which options remove solids from water? Select all that apply.
- Question 46 – According to the Bio-Medical Waste Management Rules,2016,which statements are correct?
- Question 47 – A family compares yearly pollution-related health costs. City1 has high exposure probability .1/cost10 lakh, mild .4/cost8 lakh, and low .5/cost4…
- Question 48 – Solve x-2y+z=34, 2x+y+z=102, x+y-3z=17. Find x+y+z,to two decimals.
- Question 49 – Evaluate 0(4x)/( x)\,dx,to two decimals.
- Question 50 – A stirred tank initially has 500 L brine at 200 g/L. Feed at 100 g/L enters at 15 L/min and an equal fully mixed flow leaves. The equation is…
- Question 51 – Aerobic biomass yield on glucose is .4 g/g. Glucose has molecular weight 180 g/mol and biomass is C 5H 7O 2N with molecular weight 113 g/mol. With no…
- Question 52 – The shown storm hyetograph produces 12.5 mm direct runoff. Find its φ-index in mm/hour, to two decimals.
- Question 53 – Subcatchments P, Q, R, S have areas 750,1000,1500,2000 ha;runoff coefficients .5,.6,.6,.7;and concentration times 1,2,3,4 hours. The catchment and…
- Question 54 – A confined aquifer is 30 m thick with K=5 m/day and porosity .3. Observation wells X, Y are at radii100,200 m from a fully penetrating pumping well.…
- Question 55 – Pipeline O–P–Q–R divides into parallel branches X, Y, Z between P and Q. Dimensions are shown. All pipes have friction factor .02;use g=10 m/s². The…
- Question 56 – A circular sewer with Manning n=.01 and slope1:100 flows80% full at 2 m³/s. Find diameter in metres, to three decimals.
- Question 57 – A batch test reduces a first-order toxic compound from 210-3 M to 210-4 M in 10 min. At the same temperature, a field plug-flow reactor treats1…
- Question 58 – A 2 MLD treatment plant uses RO. TDS rejection is 95%,water recovery70%,and feed TDS8000 ppm. Find reject-stream TDS in g/L, to one decimal.
- Question 59 – A boiler burns1 kg/s coal containing3% sulfur. Assume all sulfur becomes SO₂ and no sulfur remains in ash. Find SO₂ emissions in integer kg/day.
- Question 60 – A dispersoid has spherical equal-density particles. Diameters1,10,100 µm have respective counts1000,500,10 and number-removal efficiencies99%,75%,10%.…
- Question 61 – An incandescent bulb used2 hours/day consumes12.2 kWh/month. Coal electricity yield is 2 kWh/kg and PM₁₀ emission is 7 g/kg coal. An LED uses…
- Question 62 – A street sweeper starts at P, ends at S, and must traverse every street at least once. Edge lengths in km are shown. Find the minimum total distance…
- Question 63 – Waste C 60H 135O 50N 5 is composted aerobically. All ammonia escapes;air contains 23% oxygen by mass and actual air is 100% above stoichiometric.…
- Question 64 – An industry emits CO₂5 kg/day, CH₄.5 kg/day, and N₂O.1 kg/day, but flares all methane before release. GWP factors are CO₂1,CH₄21,N₂O310. Find annual…
- Question 65 – Hand-pump water near a landfill contains 1 mg/L arsenic. Oral cancer potency is 1.75 (kg·day)/mg. A 70 kg person drinks2 L/day for 10 years;average…