JKSSB Scientist - 'A' 2025 Solved Question Paper

Question 1

The upper part of the planet Earth's interior is known as

Accepted Answer

Option D: Lithosphere. The Lithosphere (from Greek *lithos* meaning stone) comprises the rigid outermost solid shell of Earth, including the entire continental and oceanic crust and the uppermost brittle mantle.

Question 2

The part of the earth in which life exists in any form i.e., plants, animals and humans is referred to as:

Accepted Answer

Option C: Biosphere. The Biosphere is the global ecological zone comprising all living organisms (plants, animals, microorganisms, humans) and the terrestrial, aquatic, and atmospheric zones supporting life.

Question 3

The atmosphere of the earth can be defined as

Accepted Answer

Option B: Envelope of air mass. The Atmosphere is the gaseous envelope of mixed air mass retained around the planet Earth by gravitational attraction.

Question 4

The study of relationships and interactions between biotic and abiotic components is known as

Accepted Answer

Option A: Ecology. Ecology (coined by Ernst Haeckel in 1866) is the scientific study of the interactions and functional relationships between living organisms (biotic) and their physical and chemical environment (abiotic).

Question 5

The functional unit in ecology is

Accepted Answer

Option C: Ecosystem. An Ecosystem (term coined by A.G. Tansley in 1935) is the fundamental structural and functional unit of ecology where living communities interact with abiotic components through energy flows and nutrient cycles.

Question 6

Within an ecosystem any physical entity that occupies space, and can be seen, smelled or felt, is known as.

Accepted Answer

Option B: Matter. In environmental physics and chemistry, Matter is defined as any physical substance that has mass and occupies space, existing in solid, liquid, gaseous, or plasma phases.

Question 7

The ability to perform work is known as

Accepted Answer

Option A: Energy. In physics and thermodynamics, Energy is defined as the quantitative capacity or ability of a physical system to perform work.

Question 8

Identify the wrong statements:
A) The Coriolis force acts perpendicular to the direction of motion
B) Pressure gradient force acts in the direction of low pressure
C) Both (A) and (B)
D) Pressure gradient force and Coriolis force are always in opposite direction

Accepted Answer

Option D: Pressure gradient force and Coriolis force are always in opposite direction. Statements A and B are true (Coriolis force acts at right angles to wind velocity; PGF acts from high to low pressure). Statement D is wrong because PGF and Coriolis force act perpendicular to each other in geostrophic wind balance and only oppose each other under strict balance perpendicular to isobars.

Question 9

Frontal inversion is caused when a

Accepted Answer

Option B: Cold air mass passes under a warm air mass. A Frontal Inversion occurs along a weather front when a dense Cold Air Mass wedges and passes underneath a lighter, less dense Warm Air Mass, forcing the warm air aloft and causing temperature to increase with height across the frontal boundary.

Question 10

Which of the following UV rays cannot penetrate through stratosphere while entering the earth surface.

Accepted Answer

Option C: UVC. UVC radiation (short wavelengths $100	ext{--}280	ext{ nm}$) possesses the highest energy and is completely absorbed by stratospheric oxygen and ozone molecules ($O_2, O_3$), preventing it from reaching the Earth's surface (UVA reaches the surface, UVB is partially absorbed).

Question 11

Identify one correct statement:

Accepted Answer

Option C: DALR is greater than SALR because ascending saturated air releases latent heat by converting water vapor into water droplets and slows down the cooling process. The Dry Adiabatic Lapse Rate ($	ext{DALR} = 9.8^\circ	ext{C/km}$) is greater than the Saturated Adiabatic Lapse Rate ($	ext{SALR} pprox 5	ext{--}6^\circ	ext{C/km}$) because rising saturated air releases latent heat of condensation as water vapor condenses into droplets, which warms the parcel and slows down its rate of cooling. Choice C.

Question 12

If $	ext{DALR} > 	ext{ELR}$, atmospheric conditions will be:

Accepted Answer

Option B: Subadiabatic. When the Environmental Lapse Rate is less than the Dry Adiabatic Lapse Rate ($	ext{ELR} < 	ext{DALR}$), the atmosphere is Subadiabatic, creating a statically Stable atmosphere where displaced air parcels return to their equilibrium level.

Question 13

Match the type of atmospheric stability to the appropriate PG (Pasquill-Gifford) Stability categories:
Set-A (Stability):
i. Unstable
ii. Neutral
iii. Stable

Set-B (PG Classes):
1. E-F
2. A-B-C
3. D

Choose the Correct Option:

Accepted Answer

Option A: (i)-(2); (ii)-(3), (iii)-(1). In Pasquill-Gifford atmospheric dispersion modeling: i -> 2 (Unstable: Classes A Extremely Unstable, B Moderately Unstable, C Slightly Unstable), ii -> 3 (Neutral: Class D), iii -> 1 (Stable: Classes E Slightly Stable, F Moderately Stable). Correct match: (i)-(2); (ii)-(3), (iii)-(1).

Question 14

Which of the following forces is negligible in particle dynamics?

Accepted Answer

Option B: Repulsion forces. In atmospheric aerosol and particulate dynamics, the dominant governing forces are Gravity, Fluid Drag/Resistance, and Buoyancy; intermolecular Electrostatic Repulsion forces between macroscopic aerosol particles are negligible.

Question 15

In open systems:

Accepted Answer

Option D: Both energy and matter will flow. In thermodynamics and ecology, an Open System (such as a living organism or natural ecosystem) freely exchanges Both Energy and Matter across its boundaries with the surrounding environment.

Question 16

Which curve shows the population growth of every organism in the environment with carrying capacity?

Accepted Answer

Option C: S-curve. Under real environmental constraints with limiting resources and carrying capacity ($K$), population growth of organisms follows the Sigmoid / S-shaped Logistic Growth Curve ($dN/dt = rN(1 - N/K)$).

Question 17

Due to climate change, species extinction may occur at:

Accepted Answer

Option C: Higher latitudes and higher elevations. Global warming forces species to shift their geographic ranges poleward and upslope. High-altitude mountain summits and high-latitude arctic species face severe extinction ('mountaintop extinction' / edge of range) because they have no higher elevations or latitudes to migrate to.

Question 18

A large regional unit characterized by vegetation type and fauna in a specific climatic zone:

Accepted Answer

Option B: Biome. A Biome is a major regional terrestrial community of plants and animals (e.g. Tundra, Taiga, Tropical Rainforest, Desert) defined by distinct climatic patterns and dominant vegetation physiognomy.

Question 19

In the logistic growth curve for population growth, the effect of environmental resistance is observed in:

Accepted Answer

Option C: Deceleration phase. In the logistic S-curve, Environmental Resistance begins to decelerate the initial exponential growth rate during the Deceleration Phase as the population density approaches the carrying capacity ($K$).

Question 20

A unit of land with natural boundary having different patches of ecosystems is called as:

Accepted Answer

Option A: Landscape. In landscape ecology, a Landscape is defined as a heterogeneous land area composed of a mosaic of interacting ecosystem patches across natural geomorphic boundaries.

Question 21

Match the following thermodynamic concepts:
Set-A:
1. System
2. Closed System
3. Open System
4. Surroundings

Set-B:
i. Rest of the universe beyond the defined boundary of the system
ii. Both energy and matter can flow across the boundary
iii. Anything with an imaginary or real boundary around
iv. Energy is allowed to flow across boundary, but matter is not allowed

Choose the Correct Option:

Accepted Answer

Option D: (1)-(iii), (2)-(iv), (3)-(ii), (4)-(i). 1 -> iii (System: specified quantity of matter/region enclosed by boundary), 2 -> iv (Closed System: energy exchange permitted, matter fixed), 3 -> ii (Open System: both energy and matter exchange), 4 -> i (Surroundings: rest of universe outside boundary). Correct match: (1)-(iii), (2)-(iv), (3)-(ii), (4)-(i).

Question 22

Consider the following statements:
i. Energy can neither be created nor destroyed
ii. When work is done there will always be some inefficiency
iii. Every bit of energy can be accounted for while taking part in the process under study
iv. Some portion of the energy put into the process will end up as waste heat
Which of the above statements are correct for First Law of thermodynamics?

Accepted Answer

Option C: (i), (iii). The First Law of Thermodynamics (Law of Conservation of Energy) states that energy cannot be created or destroyed (i), and the total energy of an isolated system remains constant so every bit is accounted for ($\Delta U = Q - W$) (iii). (Statements ii and iv describe the Second Law and entropy/irreversibility). Correct: (i), (iii).

Question 23

Match the following thermal concepts:
Set-A:
1. Specific heat
2. Latent heat of fusion
3. Internal energy
4. Latent heat of vaporization

Set-B:
i. Energy stored in the system
ii. Energy required to cause phase change from liquid to vapour
iii. Energy required to cause phase change from solid to liquid
iv. Amount of energy required to raise the temperature of unit mass of substance by 1 degree

Choose the Correct Option:

Accepted Answer

Option C: (1)-(iv), (2)-(iii), (3)-(i), (4)-(ii). 1 -> iv (Specific heat: heat required to raise unit mass by $1^\circ	ext{C}$), 2 -> iii (Latent heat of fusion: solid to liquid phase change at melting point), 3 -> i (Internal energy: microscopic molecular energy stored in system), 4 -> ii (Latent heat of vaporization: liquid to vapor phase change at boiling point). Correct match: (1)-(iv), (2)-(iii), (3)-(i), (4)-(ii).

Question 24

Mixing height is:

Accepted Answer

Option B: Height above the earth surface to the base of inversion aloft. In atmospheric dispersion meteorology, the Mixing Height is defined as the vertical distance from the Earth's ground surface up to the Base of the elevated Inversion layer aloft, within which buoyant pollutants are vigorously dispersed by convection.

Question 25

The anemometer at 10m height from the earth's surface measures the average wind speed as 10.2 m/s. The mixing height is 500m. The ventilation coefficient will be?

Accepted Answer

Option C: 5100 m^2/s. Ventilation Coefficient ($VC$) is calculated as: $VC = 	ext{Mixing Height } (H) 	imes 	ext{Average Wind Speed } (u) = 500	ext{ m} 	imes 10.2	ext{ m/s} = 5100	ext{ m}^2/	ext{s}$. (Values $>6000	ext{ m}^2/	ext{s}$ indicate good pollutant dispersion; $<2000	ext{ m}^2/	ext{s}$ indicate severe pollution trapping).

Question 26

Consider the following pairs:
Set-A:
1. Organisms
2. Population
3. Biological community
4. Aquatic systems

Set-B:
i. Primary lakes, rivers and marine ecosystems
ii. The populations of plants, animals, bacteria and fungi having distinct species composition and structures
iii. Group of individuals inhabiting each area having group characteristics
iv. Basic unit of study in ecology to understand the form, physiology and behaviour

Which one among the pairs given below is correct:

Accepted Answer

Option A: (1)-(iv), (2)-(iii), (3)-(ii), (4)-(i). 1 -> iv (Organism: basic ecological unit of form/physiology), 2 -> iii (Population: group of conspecific individuals in an area), 3 -> ii (Biological community: interacting populations of multiple species), 4 -> i (Aquatic systems: lotic/lentic waters and marine ecosystems). Correct match: (1)-(iv), (2)-(iii), (3)-(ii), (4)-(i).

Question 27

Consider the following pairs:
Set-A:
1. Autotrophs
2. Photoautotrophs
3. Photoheterotrophs
4. Chemotrophs

Set-B:
i. Obtain carbon from reduced carbon compounds generated by other organisms
ii. Obtain energy from either inorganic or organic carbon sources
iii. They obtain carbon from inorganics sources
iv. Photosynthetic organisms that obtain their carbon from inorganic sources

Which one among the pairs given below is correct:

Accepted Answer

Option B: (1)-(iii), (2)-(iv), (3)-(i), (4)-(ii). 1 -> iii (Autotrophs: fix inorganic carbon/CO2 into biomass), 2 -> iv (Photoautotrophs: use sunlight for energy and inorganic CO2 for carbon), 3 -> i (Photoheterotrophs: use sunlight for energy but require organic carbon), 4 -> ii (Chemotrophs: obtain energy from chemical oxidation of inorganic/organic compounds). Correct match: (1)-(iii), (2)-(iv), (3)-(i), (4)-(ii).

Question 28

Major driving force in the carbon cycle is

Accepted Answer

Option A: Photosynthesis. Photosynthesis ($6CO_2 + 6H_2O + h
u ightarrow C_6H_{12}O_6 + 6O_2$) conducted by terrestrial green plants and marine phytoplankton is the primary biological driving mechanism that sequesters atmospheric $CO_2$ into global organic carbon reservoirs.

Question 29

Which one of the following is the major sink of carbon

Accepted Answer

Option C: Oceans. The Oceans represent the largest active global sink of carbon on Earth, holding approximately 38,000–40,000 Gt of carbon (largely in dissolved bicarbonate $HCO_3^-$ and carbonate ions) compared to ~850 Gt in the atmosphere.

Question 30

In the lakes, nitrogen is found usually in the form of

Accepted Answer

Option C: NO3-. In well-oxygenated surface lake waters, dissolved inorganic nitrogen is predominantly oxidized through bacterial nitrification ($NH_4^+ ightarrow NO_2^- ightarrow NO_3^-$) into Nitrate ($	ext{NO}_3^-$), the primary assimilable form of nitrogen for aquatic plants and phytoplankton.

Question 31

Consider the following statements:
i. Wind is air in motion relative to the earth's surface
ii. Wind is air in motion relative to atmosphere.
iii. Wind is air in motion relative to Earth's rotation.
iv. Vertical motion of the wind is responsible for the movement of pollutants.
Which of the above statements are correct?

Accepted Answer

Option A: (i), (iv). Statements i and iv are correct: Wind is meteorologically defined as air moving horizontally and vertically relative to the Earth's ground surface (i), and turbulent vertical winds/convection govern the vertical dispersion of air pollutants (iv). Correct: (i), (iv).

Question 32

Consider the following statements:
i. The specific humidity is an index of humidity
ii. The specific humidity is a dimensionless index of humidity that changes with pressure
iii. The specific humidity is a dimensionless index of humidity that does not change with pressure or temperature
iv. Specific humidity indices are not commonly used in air quality studies
Which of the above statements are correct?

Accepted Answer

Option C: (i), (iii). Specific humidity ($q = rac{m_v}{m_v + m_d} pprox 	ext{g vapor / kg moist air}$) is an absolute mass ratio index of moisture (i) that is conservative and does not change when an air parcel expands or is heated/cooled without condensation (iii). Correct: (i), (iii).

Question 33

The pressure on a map is depicted by

Accepted Answer

Option B: Isobar. An Isobar is a line on a meteorological weather map connecting geographical points of equal atmospheric barometric pressure reduced to sea level.

Question 34

In situ bioremediation stimulating microorganisms within

Accepted Answer

Option A: Vadose zone. Bioventing and in situ unsaturated bioremediation stimulate indigenous aerobic bacteria within the Vadose Zone (unsaturated soil zone above the water table) by injecting low-flow oxygen/air and nutrients.

Question 35

Consider the following statements:
i. In intrinsic bioremediations, the contaminants should be organic compounds.
ii. In intrinsic bioremediation, natural biodegradation occurs slower than migration.
iii. The site requirement for intrinsic bioremediation includes adequate supply of trace nutrients.
iv. In intrinsic bioremediation, adequate pH buffering is required to counter the alkaline environment that results from microbial activity.
Which of the above statements are correct?

Accepted Answer

Option C: (i), (iii). Statements i and iii are correct: Intrinsic Bioremediation (natural attenuation) relies on indigenous microbes degrading biodegradable Organic petroleum/hydrocarbon contaminants (i), requiring native subsurface presence of electron acceptors ($O_2, NO_3^-$) and trace inorganic nutrients (iii). (Statement ii is false because degradation must be faster than plume migration to prevent exposure). Correct: (i), (iii).

Question 36

Biodegradation occurs in:

Accepted Answer

Option C: Aerobic and anaerobic both. Microbial biodegradation of organic matter occurs under Both Aerobic conditions (using molecular $O_2$ as terminal electron acceptor producing $CO_2$ and $H_2O$) and Anaerobic conditions (methanogenesis, sulfate reduction, denitrification producing $CH_4, H_2S, N_2$).

Question 37

Consider the following statements:
i. Biodegradation converts the original material into volatile matter
ii. Biodegradation converts the original material into water, carbon dioxide and minerals.
iii. Biodegradation includes heterotrophic bacteria.
iv. Biodegradation breaks down large polymers into monomers or oligomers.
Which of the above statements are correct?

Accepted Answer

Option A: (ii), (iv). Statements ii and iv are defining stages: Complete mineralization breaks down organic macromolecules/polymers into monomers (iv) and ultimately mineralizes them into non-toxic $CO_2$, $H_2O$, and inorganic minerals (ii). Correct: (ii), (iv).

Question 38

Consider the following statements:
i. Phytoremediation is an alternative to engineering procedures that are usually more destructive to the soil.
ii. Phytoremediation is limited to the impervious zone of soil.
iii. Phytoremediation technologies are not available for various environments and types of contaminants.
iv. Phytoremediation has limited application where the concentrations of contaminants are toxic to plants
Which of the above statements are not correct?

Accepted Answer

Option B: (ii), (iii). Statements ii and iii are incorrect: Phytoremediation operates in the root rhizosphere/vadose zone (not impervious bedrock - ii is false), and standardized plant technologies exist across wetlands, soil, and groundwater (iii is false). Statements i and iv are true. Correct: (ii), (iii) are not correct.

Question 39

Biomagnification occurs when

Accepted Answer

Option B: Organisms at the top of the food chain concentrate the material above its concentration in the surrounding soil or water.. Biomagnification (trophic magnification) is the progressive increase in concentration of a persistent, lipophilic, non-biodegradable xenobiotic (e.g. DDT, Methylmercury, PCBs) in tissues of organisms at successively Higher Trophic Levels (top predators) compared to ambient water/soil concentrations.

Question 40

Consider the following statements:
i. An ecosystem is much smaller than a biome
ii. A biome is a large area with similar flora, fauna and microorganisms
iii. Ecosystem does not fail if it doesn't remain in balance
iv. Tropical dry forests are not among major biomes of the world
Which of the above statements are correct?

Accepted Answer

Option D: (i), (ii). Statements i and ii are correct: An ecosystem (e.g. a pond or forest patch) is a localized functional unit nested within a vast regional Biome (i), which encompasses broad regional flora and fauna adapted to a specific macroclimate (ii). (Statement iii is false as ecological imbalance collapses ecosystems; iv is false). Correct: (i), (ii).

Question 41

A food chain is

Accepted Answer

Option A: path of food from producer to final consumer. A Food Chain is the linear unidirectional feeding sequence showing the transfer of energy and organic matter starting from primary Producers (autotrophs) through successive trophic levels to top predatory Consumers.

Question 42

The hydrologic cycle does not comprise

Accepted Answer

Option C: Diffusion and dispersion. The planetary Hydrologic Cycle comprises physical transport processes: Evaporation, Transpiration, Condensation, Precipitation, Infiltration, Percolation, and Surface/Groundwater Runoff. 'Diffusion and dispersion' are mass solute transport mechanisms in fluid mechanics, not macroscopic bulk water cycle stages.

Question 43

The true color is

Accepted Answer

Option A: Direct measurement of humic substances in the water. True Color of water is the color resulting purely from dissolved colloidal organic compounds (primarily natural Humic and Fulvic Acids) measured directly against platinum-cobalt (Pt-Co / Hazen) standards after centrifuging or filtering out all suspended turbidity.

Question 44

Consider the following pairs:
1. Turbidity: Measure of the extent to which light is absorbed or scattered by suspended matter
2. Turbidity: Measure of the extent to which light is absorbed or scattered by dissolved matter
3. Turbidity: Turbidity is not a direct quantitative measure of suspended solids
4. Turbidity: Soaps and detergents do not produce stable colloids that cause turbidity
Which of the above pairs match correctly?

Accepted Answer

Option C: 1 and 3. Pairs 1 and 3 are correct: Turbidity is an optical property measuring light scattered/absorbed by suspended particulate matter in Nephelometric Turbidity Units (NTU - 1), and because scattering depends on particle shape and refractive index, turbidity is not a direct quantitative mass concentration of total suspended solids (3). Correct: 1 and 3.

Question 45

Suspended organic solids:

Accepted Answer

Option B: Produce objectionable byproducts. Suspended organic solids in domestic wastewater and polluted waterways undergo anaerobic decomposition and putrefaction, generating highly Objectionable Byproducts including volatile fatty acids, offensive sulfurous gases ($H_2S$, mercaptans), and sludge deposits.

Question 46

Size ranges of dissolved, colloidal and suspended substances are:
i. $10^{-5}	ext{ to }10^{-6}\ \mu	ext{m}$
ii. $10^{-3}	ext{ to }1\ \mu	ext{m}$
iii. $10^{-5}	ext{ to }10^{-1}	ext{ mm}$
iv. $10^{-8}	ext{ to }10^{-6}	ext{ mm}$
v. $1	ext{ to }10^2\ \mu	ext{m}$
vi. $10^{-3}	ext{ to }10	ext{ mm}$
Choose the Correct Option for [Dissolved, Colloidal, Suspended]:

Accepted Answer

Option C: iv, ii, v. In environmental water classification: Dissolved solids = $< 10^{-3}\ \mu	ext{m}$ ($< 1	ext{ nm} = 10^{-8}	ext{--}10^{-6}	ext{ mm}$ $\implies$ iv), Colloidal particles = $10^{-3}\ \mu	ext{m}	ext{ to }1\ \mu	ext{m}$ (1 nm to 1 $\mu	ext{m}$ $\implies$ ii), Suspended solids = $> 1\ \mu	ext{m}$ ($1	ext{ to }100\ \mu	ext{m}$ $\implies$ v). Correct: iv, ii, v.

Question 47

Alkalinity is a measure of

Accepted Answer

Option C: The ability of water to neutralize acids. Alkalinity is defined chemically as the Acid-Neutralizing Capacity (ANC) of water, representing the sum of all titratable bases (chiefly bicarbonate $HCO_3^-$, carbonate $CO_3^{2-}$, and hydroxide $OH^-$) capable of neutralizing added strong acid to a pH of ~4.5.

Question 48

Hardness is classified based on

Accepted Answer

Option C: Cations and anions with which it associates. Water Hardness is classified based on divalent metallic cations ($Ca^{2+}, Mg^{2+}$) and the associated anions: Carbonate/Temporary Hardness (associated with $HCO_3^-, CO_3^{2-}$) and Non-Carbonate/Permanent Hardness (associated with $SO_4^{2-}, Cl^-$).

Question 49

Consider the following pairs:
Set-A:
1. BOD
2. COD
3. TOC
4. Ultimate BOD

Set-B:
i. Measure of natural organic matter
ii. BOD equal to the initial oxygen equivalent of the water
iii. Organic matter chemically oxidized
iv. Amount of oxygen consumed during microbial utilization of organics
v. Conversion of substrates to cells

Which one among the pairs given below is correct:

Accepted Answer

Option B: (1)-(iv), (2)-(iii), (3)-(i), (4)-(ii). 1 -> iv (BOD: dissolved oxygen consumed by aerobic microorganisms metabolizing organic matter), 2 -> iii (COD: oxygen required to chemically oxidize organic compounds using dichromate), 3 -> i (TOC: direct instrumental combustion measure of total organic carbon), 4 -> ii (Ultimate BOD $L_0$: total stoichiometric oxygen required for complete bio-oxidation). Correct match: (1)-(iv), (2)-(iii), (3)-(i), (4)-(ii).

Question 50

The probability distribution that characterizes some aspects of sampling variability is known as

Accepted Answer

Option B: Sampling distribution. In inferential statistics, a Sampling Distribution is the theoretical probability distribution of a sample statistic (e.g. sample mean $ar{x}$, sample variance $s^2$) obtained through repeated random sampling from a population.

Question 51

Consider the following statements:
i. Student's t distribution depends on the quantity called degree of freedom
ii. Student's t distribution is symmetric, and bell shaped
iii. Student's t distribution have a smaller standard deviation
iv. As the sample size increases the student's t distribution approaches Poisson distribution
Which of the above statements are correct?

Accepted Answer

Option C: (i), (ii). Statements i and ii are correct: Student's t-distribution is completely parameterized by its Degrees of Freedom ($df = n-1$) (i), and is symmetrical, unimodal, and bell-shaped centered at 0 with heavier tails than the normal curve (ii). (Statement iii is false as variance is larger than standard normal; iv is false as it approaches the Normal distribution, not Poisson). Correct: (i), (ii).

Question 52

In one of the monitoring experiments conducted in the field, the following concentrations of $	ext{NO}_x$ in $\mu	ext{g/m}^3$ were obtained:
$75.83, 76.03, 82.35, 82.7, 87.08, 88.25, 97.43, 108.12, 125.28$
What is the median?

Accepted Answer

Option C: 87.08 ug/m^3. For $n = 9$ ordered observations, the Median is the middle value at position $\frac{n+1}{2} = \frac{10}{2} = 5^{	ext{th}}$ position: $87.08\ \mu	ext{g/m}^3$.

Question 53

The standard deviation of data set is

Accepted Answer

Option C: Square root of variance. By mathematical definition, Standard Deviation ($\sigma$ or $s$) is the positive Square Root of the Variance ($\sigma = \sqrt{	ext{Variance}}$).

Question 54

In one of the water quality experiments in the field the following concentration of $	ext{NO}_3$ was obtained in mg/l:
$46, 46, 50, 54, 54$
The variance of the above experimental data is 12.8. What is the standard deviation?

Accepted Answer

Option A: 3.57 mg/l. $	ext{Standard Deviation} = \sqrt{	ext{Variance}} = \sqrt{12.8} \approx 3.5777	ext{ mg/l} \approx 3.57	ext{ mg/l}$.

Question 55

Consider the following statements:
i. Lognormal distribution fits the skewed data sets
ii. In the normal distribution curve, around 95% of the values are withing one standard deviation of the mean
iii. The normal distribution curve is not symmetrical about its central line
iv. Normal distribution fits the symmetrical data sets
Which of the above statements are not correct?

Accepted Answer

Option B: (ii), (iii). Statements ii and iii are incorrect: In a normal distribution, ~68.2% (not 95%) of values lie within $\pm 1\sigma$ of the mean (ii is false), and the normal curve is strictly symmetrical about $\mu$ (iii is false). Statements i and iv are correct. Therefore, the statements that are NOT correct are (ii), (iii).

Question 56

Consider the following pairs:
Set - A (Waste Category):
1. Vegetable residues and garbage
2. Pulp and paper waste
3. Radioactive substance
4. Pathological waste

Set - B (Classification):
i. Hazardous waste
ii. Municipal Solid waste
iii. Biomedical waste
iv. Industrial waste

Which one among the pairs given below is correct:

Accepted Answer

Option B: (1)-(ii), (2)-(iv), (3)-(i), (4)-(iii). 1 -> ii (Vegetable/kitchen garbage: Municipal Solid Waste MSW), 2 -> iv (Pulp and paper sludge: Non-hazardous Industrial waste), 3 -> i (Radioactive substances: Hazardous Nuclear Waste), 4 -> iii (Pathological/human tissues: Biomedical Waste). Correct match: (1)-(ii), (2)-(iv), (3)-(i), (4)-(iii).

Question 57

To obtain the dry mass of solid waste material and to limit the vaporization of volatile materials, the solid waste material is dried in an oven at:

Accepted Answer

Option A: 77°C for 24 hours. To determine dry mass of solid waste without thermal decomposition and volatilization of volatile organic compounds, standard solid waste characterization protocols specify gentle oven drying at $77^\circ	ext{C}$ for 24 hours (EPA/ASTM standards).

Question 58

If 'a' is an initial mass of solid waste sample and 'b' is mass of sample after drying. What is the formulae moisture content (in %)?

Accepted Answer

Option D: ((a - b) / a) * 100. Moisture content on a wet-weight basis is calculated as: $\%	ext{ Moisture} = \frac{	ext{Initial Wet Mass } (a) - 	ext{Dry Mass } (b)}{	ext{Initial Wet Mass } (a)} 	imes 100 = \left(\frac{a - b}{a}ight) 	imes 100$.

Question 59

As per the succession of environmental laws, which order among the following is correct?
I. Water (Prevention and Control of Pollution) Act
II. Public Liability Act
III. Air (Prevention and Control of Pollution) Act
IV. Environment Protection Act
Choose the Correct Option:

Accepted Answer

Option D: I, III, IV, II. Chronological timeline of Indian environmental enactments: I. Water Act = 1974 $->$ III. Air Act = 1981 $->$ IV. Environment (Protection) Act = 1986 $->$ II. Public Liability Insurance Act = 1991. Correct sequence: I, III, IV, II.

Question 60

Which of the following ministry is responsible at the central level for planning, promotion, coordination and overseeing the implementation of environmental pollution legislations?

Accepted Answer

Option C: Ministry of Environment, Forest and Climate Change. The Ministry of Environment, Forest and Climate Change (MoEFCC), Government of India, is the nodal central ministry responsible for formulating environmental policies, coordinating pollution control, and administering the Water, Air, and EP Acts.

Question 61

Consider the following pairs:
Set - A (Act):
1. The Factories Act, 1948
2. The Atomic Energy Act, 1962
3. Motor Vehicle Act, 1988
4. Wildlife Protection Act, 1972

Set - B (Mandate):
i. Adequate ventilation and reasonable temperature maintenance
ii. The protection of wild animals, birds and plants
iii. Prevention of radiation hazards and guarantee of public safety
iv. Legislative provisions regarding licensing of drivers and registration of motor vehicles

Which one among the pairs given below is correct:

Accepted Answer

Option C: (1)-(i), (2)-(iii), (3)-(iv), (4)-(ii). 1 -> i (Factories Act 1948: Section 13 ventilation/temperature standards), 2 -> iii (Atomic Energy Act 1962: radiological safety), 3 -> iv (Motor Vehicles Act 1988: vehicle emission norms & registration), 4 -> ii (Wildlife Protection Act 1972: conservation of flora/fauna). Correct match: (1)-(i), (2)-(iii), (3)-(iv), (4)-(ii).

Question 62

The compost or humus of organic material is end product remaining after

Accepted Answer

Option D: Assimilatory and Dissimilatory bacterial activity. Composting involves both Dissimilatory bacterial metabolism (mineralizing complex carbon compounds into $CO_2, H_2O$, and energy) and Assimilatory bacterial metabolism (synthesizing cellular biomass and complex dark aromatic Humus polymers).

Question 63

Major contributors to acid rain are:

Accepted Answer

Option A: Sulphur oxides and nitrogen oxides. Acid precipitation ($pH < 5.6$) is caused by atmospheric oxidation and hydration of anthropogenic Sulfur Oxides ($	ext{SO}_2 ightarrow 	ext{H}_2	ext{SO}_4$) and Nitrogen Oxides ($	ext{NO}_x ightarrow 	ext{HNO}_3$).

Question 64

Which of the following initiates the breakdown of ozone in the stratosphere?

Accepted Answer

Option B: Chlorine. Photolysis of chlorofluorocarbons (CFCs) by solar UV releases free Chlorine Radicals ($\cdot Cl$), which act as catalytic agents initiating catalytic destruction cycles of stratospheric ozone ($\cdot Cl + O_3 ightarrow ClO\cdot + O_2$).

Scientist - 'A'2025

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JKSSB — Scientist - 'A' (2025)

The upper part of the planet Earth's interior is known as

The part of the earth in which life exists in any form i.e., plants, animals and humans is referred to as:

The atmosphere of the earth can be defined as

The study of relationships and interactions between biotic and abiotic components is known as

The functional unit in ecology is

Within an ecosystem any physical entity that occupies space, and can be seen, smelled or felt, is known as.

The ability to perform work is known as

Identify the wrong statements:A) The Coriolis force acts perpendicular to the direction of motionB) Pressure gradient force acts in the direction of low pressureC) Both (A) and (B)D) Pressure gradient force and Coriolis force are always in opposite direction

Frontal inversion is caused when a

Which of the following UV rays cannot penetrate through stratosphere while entering the earth surface.

Identify one correct statement:

If DALR>ELR\text{DALR} > \text{ELR}DALR>ELR, atmospheric conditions will be:

Match the type of atmospheric stability to the appropriate PG (Pasquill-Gifford) Stability categories:Set-A (Stability):i. Unstableii. Neutraliii. StableSet-B (PG Classes):1. E-F2. A-B-C3. DChoose the Correct Option:

Which of the following forces is negligible in particle dynamics?

In open systems:

Which curve shows the population growth of every organism in the environment with carrying capacity?

Due to climate change, species extinction may occur at:

A large regional unit characterized by vegetation type and fauna in a specific climatic zone:

In the logistic growth curve for population growth, the effect of environmental resistance is observed in:

A unit of land with natural boundary having different patches of ecosystems is called as:

Mixing height is:

The anemometer at 10m height from the earth's surface measures the average wind speed as 10.2 m/s. The mixing height is 500m. The ventilation coefficient will be?

Major driving force in the carbon cycle is

Which one of the following is the major sink of carbon

In the lakes, nitrogen is found usually in the form of

The pressure on a map is depicted by

In situ bioremediation stimulating microorganisms within

Biodegradation occurs in:

Biomagnification occurs when

A food chain is

The hydrologic cycle does not comprise

The true color is

Suspended organic solids:

Alkalinity is a measure of

Hardness is classified based on

The probability distribution that characterizes some aspects of sampling variability is known as

The standard deviation of data set is

In one of the water quality experiments in the field the following concentration of NO3\text{NO}_3NO3​ was obtained in mg/l:46,46,50,54,5446, 46, 50, 54, 5446,46,50,54,54The variance of the above experimental data is 12.8. What is the standard deviation?

To obtain the dry mass of solid waste material and to limit the vaporization of volatile materials, the solid waste material is dried in an oven at:

If 'a' is an initial mass of solid waste sample and 'b' is mass of sample after drying. What is the formulae moisture content (in %)?

As per the succession of environmental laws, which order among the following is correct?I. Water (Prevention and Control of Pollution) ActII. Public Liability ActIII. Air (Prevention and Control of Pollution) ActIV. Environment Protection ActChoose the Correct Option:

Which of the following ministry is responsible at the central level for planning, promotion, coordination and overseeing the implementation of environmental pollution legislations?

The compost or humus of organic material is end product remaining after

Major contributors to acid rain are:

Which of the following initiates the breakdown of ozone in the stratosphere?

Which of the following is not greenhouse gas?

Which of the following gas react with hydroxyl radical and produces CO2CO_2CO2​, H2OH_2OH2​O vapor and O3O_3O3​?

The Polluter pay principle is

The indicator organism for drinking water is

As per the succession of UNFCCC protocols, which order among the following is correct?I. Paris AgreementII. The US Mayor's Climate Protection AgreementIII. Conference of Parties (COP)IV. Kyoto ProtocolChoose the Correct Option:

Which of the following pollutant is emitted from paper mills?

In a high-volume sampler, the gases are measured using the principle of

Which of the following particles enter into the bloodstream of humans?

As per the latest records, the number of non-attainment cities in India under National Clean Air Programme (NCAP) are:

Nitrogen dioxide is naturally formed from

PAN stands for

Dispersion is equal to:

The permissible value of COD in drinking water is:

After nitrogen and oxygen, the next abundant gas in the earth's atmosphere is

The temperature at which volatile solids from water gets evaporated / ignited is:

Common ion effect is the reason for

Visakhapatnam gas tragedy occurred in 2020 is due to the leakage of

PFAS stands for

Saline soils have a pH value of

Constant frequency of sounds that are persistant across all frequencies with equal energy are classified as:

Spray ponds are primarily used for

Actinomycetes is a group of

Flame photometry is used to determine

C3H4C_3H_4C3​H4​ is a

The anamalous expansion of water occurs at / maximum density is at:

In air pollution sampling, the filter paper used for collecting particulates is made up of:

Which of the following decibel range is classified as noise pollution?

The insecticide which is resistant to biodegradation and present in soil for a longer time is called as:

Choose the statements which are correct:i. Impinger is used to capture particulatesii. Thimble is used to capture gasesiii. The flow rate in HVS is NOT constantiv. Particulate monitoring should be carried out for 24 hoursWhich of the above statements are correct?

Choose the statements which are correct:i. Ammonia is a secondary pollutantii. For ozone, 8-hour average shall be taken during daytime for analysisiii. CO2 is a primary pollutant in air pollution studiesiv. PM2.5 value is always less than PM10Which of the above statements are correct?

For steady flow of a gas:

Identify the correct statement:[Conversion at STP where 1 ppm SO2 = 2.62 mg/m3]

Identify the wrong statements:
A) The Coriolis force acts perpendicular to the direction of motion
B) Pressure gradient force acts in the direction of low pressure
C) Both (A) and (B)
D) Pressure gradient force and Coriolis force are always in opposite direction

If $\text{DALR} > \text{ELR}$ , atmospheric conditions will be:

Match the type of atmospheric stability to the appropriate PG (Pasquill-Gifford) Stability categories:
Set-A (Stability):
i. Unstable
ii. Neutral
iii. Stable

Set-B (PG Classes):
1. E-F
2. A-B-C
3. D

Choose the Correct Option:

In one of the water quality experiments in the field the following concentration of $\text{NO}_3$ was obtained in mg/l:
$46, 46, 50, 54, 54$
The variance of the above experimental data is 12.8. What is the standard deviation?

As per the succession of environmental laws, which order among the following is correct?
I. Water (Prevention and Control of Pollution) Act
II. Public Liability Act
III. Air (Prevention and Control of Pollution) Act
IV. Environment Protection Act
Choose the Correct Option:

Which of the following gas react with hydroxyl radical and produces $CO_2$ , $H_2O$ vapor and $O_3$ ?

As per the succession of UNFCCC protocols, which order among the following is correct?
I. Paris Agreement
II. The US Mayor's Climate Protection Agreement
III. Conference of Parties (COP)
IV. Kyoto Protocol
Choose the Correct Option:

$C_3H_4$ is a

Choose the statements which are correct:
i. Impinger is used to capture particulates
ii. Thimble is used to capture gases
iii. The flow rate in HVS is NOT constant
iv. Particulate monitoring should be carried out for 24 hours
Which of the above statements are correct?

Choose the statements which are correct:
i. Ammonia is a secondary pollutant
ii. For ozone, 8-hour average shall be taken during daytime for analysis
iii. CO2 is a primary pollutant in air pollution studies
iv. PM2.5 value is always less than PM10
Which of the above statements are correct?

Identify the correct statement:
[Conversion at STP where 1 ppm SO2 = 2.62 mg/m3]