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General Science and Technology

222 questions

All types222Multiple choice117Multiple select40True / False8Matching44Ordering13
Question 161Question →

Consider the following statements regarding indigenously developed Indian defense systems:
1. The Pinaka system is an indigenous Multi-Barrel Rocket Launcher (MBRL) system designed to deliver high-volume firepower in a short time frame.
2. HELINA is the helicopter-launched air-to-surface variant of the Nag anti-tank guided missile system.
Which of the statements given above is/are correct?

Show answer & explanation

Answer: Both 1 and 2

Answer

Both 1 and 2 are correct.
Both statements are factually accurate. Pinaka is an indigenous multi-barrel rocket launcher system, and HELINA represents the helicopter-launched version of the Nag anti-tank missile.

Step-by-Step Solution

1
Evaluate Statement 1 regarding Pinaka MBRL
Statement 1 is correct.
The Pinaka system was indigenously designed by DRDO's Armament Research and Development Establishment (ARDE) as a multi-barrel rocket launcher for area neutralization.
2
Evaluate Statement 2 regarding HELINA
Statement 2 is correct.
HELINA (Helicopter-launched Nag) is the air-launched derivative of the third-generation fire-and-forget Nag anti-tank guided missile (ATGM), designed for integration with combat helicopters.

Key Concept

Indigenous tactical rocket artillery and anti-tank guided missile variants in Indian defense technology
Question 162Question →

Arrange the following Indian Space Research Organisation (ISRO) launch vehicles in chronological order of their historical introduction and first successful orbital flight, from the earliest to the most recent.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological sequence of ISRO launch vehicles from earliest to most recent is Satellite Launch Vehicle-3 (SLV-3), Augmented Satellite Launch Vehicle (ASLV), Polar Satellite Launch Vehicle (PSLV), and Launch Vehicle Mark 3 (LVM3).
The sequence follows ISRO's historical technological progression: SLV-3 (1980) → ASLV (1992) → PSLV (1994) → LVM3 (2017).

Step-by-Step Solution

1
Identify the timeframe for SLV-3.
SLV-3 achieved its first successful orbital launch in 1980.
This represents the foundational phase of India's indigenous launch capability.
2
Identify the timeframe for ASLV.
ASLV recorded its first successful orbital flight in 1992.
ASLV served as a technology demonstrator between SLV-3 and PSLV.
3
Identify the timeframe for PSLV.
PSLV achieved its first successful mission in 1994.
PSLV became ISRO's primary workhorse for polar and sun-synchronous orbits.
4
Identify the timeframe for LVM3.
LVM3 completed its first successful orbital developmental flight in 2017.
LVM3 is ISRO's heavy-lift launch system designed for geostationary payloads and human spaceflight.

Key Concept

Historical evolution of ISRO's satellite launch vehicle technology
Question 163Question →

Polymerase Chain Reaction (PCR) is a biotechnology technique primarily used to amplify specific segments of DNA, producing millions of copies from a tiny sample.

Show answer & explanation

Answer: True

Answer

The statement is True. Polymerase Chain Reaction (PCR) is a foundational molecular biotechnology technique designed to selectively amplify target DNA sequences into millions or billions of copies.
The statement is accurate because Polymerase Chain Reaction (PCR) is specifically designed to isolate and amplify designated regions of DNA, generating millions of identical copies for diagnostic and analytical applications.

Step-by-Step Solution

1
Identify the biotechnology process mentioned in the statement
The technique is Polymerase Chain Reaction (PCR).
Determining the primary function of PCR is necessary to assess the accuracy of the statement.
2
Analyze the core function and mechanism of PCR
PCR uses repeated thermal cycling, primers, and DNA polymerase to exponentially synthesize copies of a target DNA region.
This molecular copying mechanism allows micro-gram or nano-gram quantities of DNA to be multiplied rapidly.
3
Verify statement validity
The statement correctly describes DNA amplification via PCR.
The statement is confirmed to be True.

Key Concept

Polymerase Chain Reaction (PCR) and DNA Amplification
Question 164Question →

Which of the following clean energy technologies directly converts solar radiation into electricity using semiconductor materials through the photovoltaic effect?

Show answer & explanation

Answer: Solar Photovoltaic Technology

Answer

Solar Photovoltaic Technology directly converts solar radiation into electrical energy using semiconductor materials.
Solar Photovoltaic Technology absorbs solar photons using semiconductor materials (such as silicon), releasing electrons to produce a direct electrical current. This is a direct physical transformation without an intermediate thermal or mechanical stage.

Step-by-Step Solution

1
Identify the primary mechanism described in the question.
The mechanism is the direct conversion of light (photons) into electricity using semiconductor materials.
Understanding the working principle distinguishes direct photon-to-electron energy conversion from thermal thermodynamic cycles.
2
Evaluate the energy conversion process of solar photovoltaic systems.
When light shines on a photovoltaic semiconductor cell, absorbed photons knock electrons free, creating an electric current.
This physical phenomenon is precisely defined as the photovoltaic effect.
3
Compare against alternative solar and clean energy technologies.
Concentrated solar power and solar thermal systems rely on thermal energy capture rather than direct semiconductor electrical conversion.
Ensures accurate technical classification among different renewable energy technologies.

Key Concept

Photovoltaic Effect and Solar PV Working Principle
Question 165Question →

In bio-imaging applications, semiconductor quantum dots exhibit size-tunable fluorescence due to quantum confinement, wherein decreasing the nanoparticle radius increases its effective electronic energy bandgap, thereby causing the emitted fluorescence spectrum to shift toward longer wavelengths (red-shift).

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Answer: False

Answer

The statement is False. Decreasing the size of a quantum dot increases its energy bandgap, which results in the emission of higher-energy photons corresponding to shorter wavelengths (a blue-shift), not longer wavelengths.
Quantum dots display quantum confinement when their physical dimensions approach the exciton Bohr radius. Decreasing the particle size widens the energy gap between the valence and conduction bands. By the fundamental relation E=hcλE = \frac{hc}{\lambda}, a larger energy gap produces higher-energy, shorter-wavelength light (blue-shifted emission). Therefore, the assertion that an increased energy bandgap yields longer wavelengths (red-shift) is scientifically incorrect.

Step-by-Step Solution

1
Analyze the relationship between quantum dot physical size and energy bandgap.
As the radius of a semiconductor quantum dot decreases below its exciton Bohr radius, spatial confinement of charge carriers increases, widening the bandgap (EgE_g).
Quantum confinement alters the electronic band structure, causing energy levels to become discrete and expanding the energy gap between the valence and conduction bands.
2
Apply the Planck-Einstein energy-wavelength equation (E=hcλE = \frac{hc}{\lambda}) to relate energy bandgap to emission wavelength.
An increase in bandgap energy (EE) leads to a shorter emitted wavelength (λ\lambda).
Energy and wavelength are inversely proportional; thus, higher photon transition energies correspond to blue-shifted (shorter wavelength) light.
3
Evaluate the statement's conclusion regarding wavelength shift.
The statement incorrectly asserts that an increased energy bandgap causes a shift toward longer wavelengths (red-shift).
A shift toward longer wavelengths implies lower energy emission, which contradicts the established phenomenon of increased bandgap energy in smaller nanoparticles.

Key Concept

Quantum Confinement Effect and Size-Tunable Optical Emission in Quantum Dots
Question 166Question →

Match the everyday devices and physical phenomena in List-I with their underlying governing physics principles in List-II:

Click a left item, then click its matching right item

Items

Operation of a perfume atomizer sprayer
Absorption of ink by blotting paper
Bending mechanism of a bimetallic thermostat strip
Shattering of a crystal glass by a sustained vocal pitch

Matches

Show answer & explanation

Answer

The correct pairings are: Operation of a perfume atomizer sprayer matches with Bernoulli's Principle; Absorption of ink by blotting paper matches with Capillary Action; Bending mechanism of a bimetallic thermostat strip matches with Differential Thermal Expansion; Shattering of a crystal glass by a sustained vocal pitch matches with Acoustic Resonance.
Each phenomenon is matched strictly with its primary physical mechanism: the perfume atomizer relies on fluid velocity creating pressure drops (Bernoulli's Principle), blotting paper uses narrow fiber channels to draw liquid (Capillary Action), bimetallic thermostats depend on unequal metal expansion rates under heat (Differential Thermal Expansion), and glass shattering occurs when forced vibrations match internal natural frequency (Acoustic Resonance).

Step-by-Step Solution

1
Analyze the fluid dynamics in an atomizer sprayer.
High fluid velocity over the nozzle causes a local pressure drop, drawing liquid up according to Bernoulli's Principle (P+12ρv2+ρgh=constantP + \frac{1}{2}\rho v^2 + \rho gh = \text{constant}).
Identify the fluid dynamic phenomenon responsible for suction in sprayers.
2
Examine the porous transport mechanism of liquid in paper.
Interconnected cellulose fibers act as fine capillaries drawing ink upward via adhesive and surface tension forces (Capillary Action).
Relate liquid movement in porous media to surface phenomena.
3
Analyze thermal behavior of bonded dissimilar metals.
Different coefficients of linear expansion (α\alpha) cause unequal length changes during temperature variations, bending the bimetallic strip.
Identify thermal properties exploited in temperature regulation switches.
4
Evaluate wave frequency matching in structural response.
Energy transfer is maximized when the driving sound frequency equals the glass structure's natural frequency (Acoustic Resonance).
Connect sound vibration phenomena to mechanical failure.

Key Concept

Everyday Applications of Classical Mechanics, Fluid Dynamics, Thermodynamics, and Wave Resonance
Question 167Question →

Consider the following statements regarding RNA Interference (RNAi) technology and nano-delivery systems in biotechnology:

1. RNA interference is a post-transcriptional gene silencing mechanism initiated by double-stranded RNA (dsRNA) molecules.
2. MicroRNAs (miRNAs) typically exhibit perfect sequence complementarity to a single specific target mRNA, leading to immediate enzymatic mRNA cleavage.
3. Lipid Nanoparticles (LNPs) act as delivery vehicles that protect delicate nucleic acids from degradation in extracellular fluids during systemic circulation.

Which of the statements given above is/are correct?

Show answer & explanation

Answer: 1 and 3 only

Answer

1 and 3 only
The correct answer states that 1 and 3 only are correct. RNAi is indeed a post-transcriptional silencing process driven by dsRNA, and Lipid Nanoparticles (LNPs) serve as crucial nanoscale delivery carriers that encapsulate RNA molecules to prevent extracellular degradation. Statement 2 is false because miRNAs usually bind with partial complementarity to exert translational repression, whereas perfect complementarity and direct mRNA cleavage are characteristic of siRNAs.

Step-by-Step Solution

1
Evaluate Statement 1 regarding RNA interference mechanism
Statement 1 is correct.
RNA interference (RNAi) is a conserved biological pathway where double-stranded RNA (dsRNA) triggers sequence-specific gene silencing at the post-transcriptional level.
2
Evaluate Statement 2 regarding miRNA complementarity and cleavage mechanism
Statement 2 is incorrect.
Small interfering RNAs (siRNAs) generally require full, perfect complementary binding to target specific mRNA for direct cleavage. MicroRNAs (miRNAs), on the other hand, typically possess partial or imperfect sequence complementarity, allowing them to target multiple distinct mRNAs and suppress translation rather than causing direct cleavage.
3
Evaluate Statement 3 regarding Lipid Nanoparticles (LNPs) as therapeutic delivery vehicles
Statement 3 is correct.
Lipid Nanoparticles (LNPs) shield sensitive nucleic acid payloads (such as siRNA or mRNA) from rapid enzymatic degradation by ribonucleases in systemic circulation and facilitate cellular uptake.

Key Concept

RNA interference mechanisms and nanomedicine drug delivery systems
Estimated Time:2m 0s
Question 168Question →

With reference to clean energy technologies and renewable energy initiatives in India, consider the following statements:

1. Green hydrogen is produced through the electrolysis of water powered by electricity derived entirely from renewable energy sources.
2. Solar Photovoltaic (PV) systems utilize parabolic mirrors to concentrate sunlight, heating a thermal fluid that drives a conventional thermodynamic steam turbine.
3. Component B of the PM-KUSUM scheme supports individual farmers in installing standalone solar-powered agriculture pumps.

Which of the statements given above are correct?

Show answer & explanation

Answer: 1 and 3 only

Answer

1 and 3 only
The correct response identifies that statements 1 and 3 are scientifically and factually accurate. Green hydrogen relies strictly on renewable energy electrolysis. Component B of PM-KUSUM focuses on individual standalone solar pumps. In contrast, statement 2 confuses solar photovoltaic technology—which converts light directly to electrical current using semiconductors—with solar thermal/concentrated solar power systems that heat working fluids to drive turbines.

Step-by-Step Solution

1
Evaluate Statement 1 regarding Green Hydrogen production.
Green Hydrogen is defined as hydrogen generated via water electrolysis using electricity produced from renewable sources (such as solar or wind), resulting in zero carbon emissions during generation. Thus, Statement 1 is correct.
Verify technical definition under National Green Hydrogen Mission guidelines.
2
Evaluate Statement 2 regarding Solar Photovoltaic technology.
Photovoltaic cells directly convert solar photon energy into electricity using semiconductor materials through the photoelectric effect. The use of mirrors to heat working fluids to drive steam turbines describes Concentrated Solar Thermal Power (CSP), not PV cells. Thus, Statement 2 is incorrect.
Distinguish between direct semiconductor conversion (PV) and thermal thermodynamic cycles (CSP).
3
Evaluate Statement 3 regarding PM-KUSUM Scheme components.
PM-KUSUM consists of three components: Component A (small solar power plants), Component B (installation of standalone solar agricultural pumps), and Component C (solarization of grid-connected agricultural pumps). Thus, Statement 3 is correct.
Verify policy features of the PM-KUSUM national solar scheme.

Key Concept

Working principles of Solar PV versus Concentrated Solar Power, definition of Green Hydrogen, and provisions of the PM-KUSUM scheme
Estimated Time:1m 15s
Question 169Question →

Epidemiological studies and public health assessments rely on precise categorization of infectious human diseases, their biological pathogens, and transmission vectors. Which of the following statements regarding communicable human diseases are correct?

Select all that apply

Show answer & explanation

Answer: Poliomyelitis is a viral infection caused by an enterovirus that is primarily transmitted through the fecal-oral route and can lead to irreversible motor paralysis.; Schistosomiasis is a parasitic disease caused by trematode flatworms that utilize freshwater snails as intermediate hosts during their lifecycle.

Answer

The correct statements are those identifying Poliomyelitis as a viral enteroviral infection spread via the fecal-oral route and Schistosomiasis as a trematode parasite infection involving freshwater snail hosts.
Poliomyelitis is caused by an enterovirus transmitted via the fecal-oral route, and Schistosomiasis is a parasitic trematode infection reliant on freshwater snails as intermediate hosts. Both statements accurately reflect physiological and epidemiological facts.

Step-by-Step Solution

1
Evaluate the pathogen class and primary transmission route of Poliomyelitis.
Poliomyelitis is accurately identified as a viral disease (enterovirus) spread by the fecal-oral route.
Confirming the biological classification confirms the statement regarding Poliomyelitis is correct.
2
Analyze the life cycle and intermediate hosts of Schistosomiasis.
Schistosomiasis is caused by trematode flatworms (blood flukes) that develop inside freshwater snails before infecting human hosts.
Confirming the parasite lifecycle confirms the statement regarding Schistosomiasis is correct.
3
Examine the causative pathogen and mode of transmission for Hepatitis A.
Hepatitis A is a viral infection (HAV) spread via fecal-oral contamination, not a vector-borne bacterial disease.
Identifying pathogen and vector misattributions demonstrates the statement regarding Hepatitis A is incorrect.
4
Examine the biological classification of Ascaris lumbricoides.
Ascaris lumbricoides is a parasitic nematode (helminthic roundworm), not a fungus.
Identifying kingdom-level misclassification demonstrates the statement regarding Ascariasis is incorrect.

Key Concept

Human Infectious Disease Etiology, Pathogen Classification, and Transmission Pathways
Estimated Time:1m 30s
Question 170Question →

Which of the following human diseases is caused by a bacterial pathogen rather than a viral, protozoan, or fungal agent?

Show answer & explanation

Answer: Pertussis

Answer

Pertussis is caused by a bacterial pathogen.
Pertussis, commonly known as whooping cough, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis.

Step-by-Step Solution

1
Identify the causative pathogen of Pertussis
Bordetella pertussis, a Gram-negative bacterium
Determines whether the disease agent is bacterial
2
Analyze the nature of the alternative disease agents
Dengue is viral (Flavivirus), Sleeping sickness is protozoan (Trypanosoma), and Ringworm is fungal (Dermatophytes)
Differentiates bacterial etiology from viral, protozoan, and fungal etiologies

Key Concept

Bacterial Disease Etiology
Estimated Time:1m 0s
Question 171Question →

In network security architecture, an Intrusion Detection System (IDS) is designed to actively block, drop, or alter malicious network packets in real time, whereas an Intrusion Prevention System (IPS) operates purely passively by monitoring network traffic and generating alerts without taking inline defensive actions.

Show answer & explanation

Answer: False

Answer

The statement is False. An Intrusion Detection System (IDS) operates passively to monitor network traffic and generate alerts, while an Intrusion Prevention System (IPS) operates inline to actively detect and block malicious traffic.
The statement is False because it reverses the core functional roles of network security monitoring systems. An Intrusion Detection System (IDS) is a passive defense technology that inspects copied network traffic, compares it against known threat signatures or anomalies, and generates log alerts without modifying packet flow. Conversely, an Intrusion Prevention System (IPS) is an active defense tool placed directly inline within the network path to detect threats and immediately block, drop, or reset malicious connections in real time.

Step-by-Step Solution

1
Identify the operational definitions of IDS and IPS in cybersecurity.
IDS focuses on passive observation and alerting, whereas IPS focuses on active inline intervention and packet blocking.
Understanding the fundamental operational mechanism of network security devices is necessary to evaluate the assertion.
2
Compare the defined mechanisms with the given statement.
The statement attributes active packet dropping to IDS and passive monitoring to IPS, reversing their actual technical capabilities.
Identifying functional inversions reveals whether a technical statement regarding network defense is accurate.

Key Concept

Operational Distinction between Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS)
Question 172Question →

Which launch vehicle developed by the Indian Space Research Organisation (ISRO) is widely referred to as the 'workhorse of ISRO' primarily due to its consistent success in placing remote sensing and earth observation satellites into Sun-Synchronous Orbits?

Show answer & explanation

Answer: Polar Satellite Launch Vehicle (PSLV)

Answer

Polar Satellite Launch Vehicle (PSLV)
The Polar Satellite Launch Vehicle (PSLV) earned the epithet 'workhorse of ISRO' because of its exceptional reliability, decade-spanning track record, and multi-payload capability in deploying earth observation satellites to polar sun-synchronous orbits.

Step-by-Step Solution

1
Identify the designated nickname and operational primary role of ISRO's satellite launch vehicles.
The Polar Satellite Launch Vehicle (PSLV) is officially recognized as the 'workhorse of ISRO'.
Since its first successful launch in 1994, PSLV has reliably delivered dozens of Indian Earth Observation satellites into polar Sun-Synchronous Orbits and has also launched iconic missions such as Chandrayaan-1 and the Mars Orbiter Mission.

Key Concept

ISRO Launch Vehicle Classification and Orbital Roles
Question 173Question →

With reference to India's launch vehicle technology developed by the Indian Space Research Organisation (ISRO), consider the following statements:

1. PSLV is a four-stage launch vehicle configured with alternating solid and liquid propulsion stages.
2. GSLV Mk II utilizes an indigenous Cryogenic Upper Stage (CUS) to place payloads of up to 2,500 kg into Geostationary Transfer Orbit (GTO).
3. LVM3 (GSLV Mk III) is designed as a four-stage vehicle using twin hypergolic liquid strap-on boosters.

Which of the statements given above are correct?

Show answer & explanation

Answer: 1 and 2 only

Answer

Statements 1 and 2 are correct. Statement 3 is incorrect because LVM3 is a three-stage launch vehicle utilizing twin solid strap-on boosters.
The option stating '1 and 2 only' is correct. PSLV operates on a four-stage alternating solid-liquid propulsion mechanism (PS1 solid, PS2 liquid Vikas engine, PS3 solid, PS4 liquid). GSLV Mk II integrates the indigenous CE-7.5 cryogenic upper stage and carries a GTO payload of around 2,250–2,500 kg. Meanwhile, LVM3 (GSLV Mk III) is a three-stage launch vehicle comprising twin S200 solid strap-on boosters, an L110 liquid core stage, and a C25 cryogenic upper stage, making statement 3 false.

Step-by-Step Solution

1
Analyze Statement 1 regarding PSLV configuration.
PSLV uses a 4-stage system alternating between solid (1st and 3rd) and liquid (2nd and 4th) engines.
Verify structural stage architecture of PSLV.
2
Analyze Statement 2 regarding GSLV Mk II payload and cryogenic stage.
GSLV Mk II features the indigenous Cryogenic Upper Stage (CE-7.5) capable of launching ~2,500 kg into GTO.
Verify cryogenic integration and GTO capacity limits.
3
Analyze Statement 3 regarding LVM3 (GSLV Mk III) design.
LVM3 is a 3-stage vehicle comprising two S200 solid strap-on boosters, an L110 twin-engine liquid core stage, and a C25 cryogenic upper stage.
Identify the incorrect classification of LVM3 stage count and booster propellant type.

Key Concept

ISRO Launch Vehicle Specifications and Stage Architectures
Question 174Question →

Consider the following statements regarding optical phenomena observed in everyday life. Which of the following statements are correct?

Select all that apply

Show answer & explanation

Answer: The twinkling of stars at night is primarily caused by atmospheric refraction due to continuous changes in the refractive index of air layers.; A mirage in hot deserts is formed because light rays bend upward and undergo total internal reflection as they pass through warmer air near the ground.

Answer

The correct statements are the ones describing starlight twinkling due to atmospheric refraction and desert mirage formation via total internal reflection.
Atmospheric refraction of starlight through turbulent air layers of varying density causes continuous fluctuation in apparent position and intensity, leading to twinkling. Similarly, a mirage in hot deserts is a classic example of total internal reflection, where light rays bend upward as they pass into warmer, less dense air near the surface until total internal reflection takes place. Both of these statements correctly identify the underlying optical principles.

Step-by-Step Solution

1
Evaluate the mechanism behind star twinkling.
Starlight enters Earth's atmosphere and passes through layers of varying density and temperature. This causes continuous atmospheric refraction, leading to rapid fluctuations in the star's apparent brightness and position (twinkling). Hence, the statement regarding star twinkling is correct.
Fluctuating refractive indices of atmospheric air layers produce starlight scintillation.
2
Evaluate the cause of the sky's blue color.
Sunlight contains all visible wavelengths. Gas molecules in the atmosphere scatter shorter blue wavelengths much more effectively than longer red wavelengths (Rayleigh scattering, where scattered intensity I∝1λ4I \propto \frac{1}{\lambda^4}). Attributing this to total internal reflection is incorrect. Hence, the statement regarding sky color is incorrect.
Rayleigh scattering governs atmospheric sky color, not internal reflection.
3
Evaluate the mechanism of mirage formation.
Near hot desert ground, air is warmer and optically rarer than cooler air higher up. Light from distant objects bends away from the normal (refraction) as it travels downward into hotter layers until the angle of incidence exceeds the critical angle, resulting in total internal reflection. This forms an inverted mirage image. Hence, the mirage statement is correct.
Total internal reflection occurring at the interface of heated air layers produces a mirage.
4
Evaluate the optical processes in a primary rainbow.
Sunlight entering a raindrop refracts (and disperses), undergoes ONE internal reflection at the back wall of the drop, and refracts again upon exiting. Two internal reflections create a weaker secondary rainbow. Hence, the primary rainbow statement is incorrect.
Primary rainbows require one internal reflection; secondary rainbows require two.

Key Concept

Atmospheric optical phenomena (Refraction, Scattering, and Total Internal Reflection)
Question 175Question →

Which of the following statements regarding clean and renewable energy technologies are correct?

Select all that apply

Show answer & explanation

Answer: Green hydrogen is produced by splitting water molecules into hydrogen and oxygen through electrolysis using renewable electricity.; Biogas generated through anaerobic digestion of organic matter consists primarily of methane and carbon dioxide.; Wind turbines convert the kinetic energy of moving air into mechanical energy and subsequently into electrical energy using a generator.

Answer

The correct statements are those describing green hydrogen electrolysis, biogas composition from anaerobic digestion, and wind turbine kinetic-to-electrical energy conversion.
Green hydrogen production, biogas composition, and wind power energy transformation are all accurately described based on established renewable energy physics and clean technology principles.

Step-by-Step Solution

1
Evaluate the statement on green hydrogen production.
Green hydrogen production relies entirely on splitting water (H2O→H2+12O2H_2O \rightarrow H_2 + \frac{1}{2}O_2) via electrolysis powered by renewable energy sources, making it a zero-emission fuel.
This statement accurately reflects the definition and clean technology pathway of green hydrogen.
2
Evaluate the statement on biogas composition.
Biogas produced by microbial breakdown of organic waste in an anaerobic environment is primarily composed of methane (CH4CH_4) and carbon dioxide (CO2CO_2).
This statement correctly describes the biochemical process and resulting gaseous mixture.
3
Evaluate the statement on solar photovoltaic mechanism.
Solar PV modules generate direct electrical current directly from sunlight photons interacting with semiconductor materials (pp-nn junctions), avoiding thermal or steam turbine stages.
Confusing PV direct conversion with solar thermal thermodynamic turbine systems is a common technical misconception.
4
Evaluate the statement on wind turbine energy conversion.
Wind turbines extract kinetic energy from moving air masses, transforming it to rotational mechanical energy and then to electrical power via magnetic induction.
This statement correctly states the fundamental energy transformation chain of wind power technology.

Key Concept

Operating Principles of Key Renewable Energy and Clean Technologies
Question 176Question →

Which clean energy technology utilizes the natural temperature difference between warm surface seawater and cold deep ocean water to vaporize a working fluid and drive a turbine for electricity generation?

Show answer & explanation

Answer: Ocean Thermal Energy Conversion (OTEC)

Answer

Ocean Thermal Energy Conversion (OTEC) is the ocean energy technology that converts solar radiation absorbed by the oceans into electric power by utilizing the thermal difference between warm surface water and cold deep water.
Ocean Thermal Energy Conversion (OTEC) operates as a thermodynamic heat engine taking advantage of the temperature difference between warm ocean surface water (heated by the sun) and cold deep water pumped from lower ocean depths.

Step-by-Step Solution

1
Identify the primary source of energy described in the prompt
The energy source relies on the temperature difference (thermal gradient) between shallow warm sea surface layers and deep cold ocean waters.
Different ocean energy technologies convert different physical phenomena (waves, tides, thermal gradients, or osmotic pressure).
2
Correlate the physical mechanism with the proper technological term
Ocean Thermal Energy Conversion (OTEC) requires a temperature difference of at least 20∘C20^\circ\text{C} (36∘F36^\circ\text{F}) between surface and deep waters to operate a Rankine thermodynamic cycle efficiently.
Warm surface water turns a low-boiling-point working fluid (such as ammonia) into vapor to spin a generator, while cold deep water condenses it back to liquid.

Key Concept

Ocean Thermal Energy Conversion (OTEC) operating principle
Question 177Question →

With reference to the applications of nanotechnology in biomedicine and healthcare, consider the following statements:

1. Gold nanoparticles exhibit localized Surface Plasmon Resonance (SPR), enabling their usage in high-sensitivity optical biosensors and targeted photothermal cancer therapy.
2. Liposomes are solid metallic nanostructures engineered to permanently integrate into host genome sequences during targeted drug delivery.
3. Dendrimers are highly branched, spherical synthetic macromolecules possessing well-defined molecular architectures that allow precise encapsulation of therapeutic agents for controlled drug release.

Which of the statements given above is/are correct?

Show answer & explanation

Answer: 1 and 3 only

Answer

1 and 3 only
The correct response identifies statements 1 and 3 as true while recognizing statement 2 as false. Gold nanoparticles utilize Surface Plasmon Resonance for diagnostics and hyperthermic tumor therapy, whereas dendrimers provide controlled drug loading due to their branched polymeric structure. Liposomes are lipid vesicles rather than metallic gene-altering particles.

Step-by-Step Solution

1
Evaluate Statement 1 regarding Gold Nanoparticles
Statement 1 is correct.
Gold nanoparticles undergo localized surface plasmon resonance (LSPR) when light interacts with conduction electrons on their surface, making them excellent candidates for biosensing, bio-imaging, and photothermal ablation of cancer cells.
2
Evaluate Statement 2 regarding Liposomes
Statement 2 is incorrect.
Liposomes are microscopic spherical vesicles composed of phospholipid bilayers surrounding an aqueous core. They are non-metallic lipid-based drug delivery vehicles and do not alter or integrate into host DNA.
3
Evaluate Statement 3 regarding Dendrimers
Statement 3 is correct.
Dendrimers are nanometer-scale, highly branched, 3D synthetic polymers with high functionality at their surface, ideal for drug encapsulation, targeted delivery, and gene therapy.

Key Concept

Nanomedicine and Nanobiotechnology Applications (Gold Nanoparticles, Liposomes, Dendrimers)
Question 178Question →

With reference to cybersecurity threats and malicious software mechanisms, consider the following statements:

1. A computer worm can self-replicate and spread across computer networks autonomously without needing to attach itself to an existing host file or program.
2. A Trojan horse actively replicates itself and infects other files across the operating system once executed by the user.

Which of the statements given above is/are correct?

Show answer & explanation

Answer: 1 only

Answer

Statement 1 only is correct. A computer worm is a standalone malware program that replicates itself in order to spread to other computers across network links without needing a host program or human action. Conversely, a Trojan horse relies on tricking a user into executing it and does not replicate or spread automatically like viruses or worms.
The statement identifying worms as autonomous, host-independent malware is accurate. Computer worms exploit network protocols and system vulnerabilities to replicate across nodes without requiring user interaction or attaching to executable host code. Conversely, Trojan horses hide malicious payloads inside seemingly harmless files and do not possess self-replication routines.

Step-by-Step Solution

1
Analyze Statement 1 regarding computer worms.
Statement 1 is verified as true. Worms use network interfaces and protocols to scan for vulnerable systems and self-propagate automatically.
Understanding the self-contained and autonomous propagation mechanism of worms in network security.
2
Analyze Statement 2 regarding Trojan horses.
Statement 2 is identified as false. Trojan horses rely on social engineering and stealth, lacking the self-replication feature of viruses and worms.
Distinguishing between malware types based on replication capabilities and delivery vectors.
3
Select the option that matches the verified statement accuracy.
Only Statement 1 is correct.
Synthesizing individual statement assessments into the correct option choice.

Key Concept

Classification and Propagation Characteristics of Computer Worms vs. Trojan Horses
Estimated Time:1m 0s
Question 179Question →

Match the following Indian Space Research Organisation (ISRO) scientific missions listed in List-I with their primary scientific objectives and operational characteristics listed in List-II:

Click a left item, then click its matching right item

Items

XPoSAT
Aditya-L1
NISAR
AstroSat

Matches

Show answer & explanation

Answer

XPoSAT matches with X-ray polarization measurement in low Earth orbit; Aditya-L1 matches with solar corona observation from the Sun-Earth L1 halo orbit; NISAR matches with dual-frequency radar imaging of land and ice surfaces; AstroSat matches with multi-wavelength astronomical observations across optical, UV, and X-ray bands.
Each ISRO scientific mission is correctly paired with its specific objective and operational domain: XPoSAT performs polarimetric X-ray study of cosmic sources; Aditya-L1 monitors the Sun from the L1 halo orbit; NISAR performs dual-frequency radar Earth imaging; and AstroSat operates as a multi-wavelength space observatory.

Step-by-Step Solution

1
Identify the primary science payload objective of XPoSAT
XPoSAT focuses on polarimetric study of cosmic X-ray sources, matching with measuring X-ray emission polarization.
The POLIX payload on XPoSAT specifically measures polarization parameters in the 8-30 keV energy band.
2
Identify the orbital placement and research domain of Aditya-L1
Aditya-L1 is placed at the L1 Lagrangian point for uninterrupted solar observation.
Lagrangian Point 1 provides an unobstructed view of the Sun without earth eclipses or occultations.
3
Identify the technological feature of NISAR
NISAR employs dual-frequency (L-band and S-band) SAR technology for Earth observation.
NASA contributes the L-band SAR and ISRO contributes the S-band SAR for surface deformation tracking.
4
Identify the primary observational capability of AstroSat
AstroSat provides multi-wavelength coverage across UV, optical, and X-ray regimes.
AstroSat carries multiple payloads operating simultaneously across different wavebands.

Key Concept

ISRO Space Exploration and Astronomy Missions
Question 180Question →

Match the human endocrine hormones in List-I with their primary physiological functions in List-II.

Click a left item, then click its matching right item

Items

Calcitonin
Vasopressin (Antidiuretic Hormone)
Oxytocin
Melatonin

Matches

Show answer & explanation

Answer

Calcitonin pairs with lowering blood calcium levels; Vasopressin pairs with increasing water reabsorption in renal tubules; Oxytocin pairs with stimulating uterine contractions and milk ejection; Melatonin pairs with regulating circadian rhythms.
Each hormone is correctly matched to its specific physiological role: Calcitonin reduces blood calcium concentrations, Vasopressin promotes renal water reabsorption, Oxytocin induces uterine contraction and lactation ejection, and Melatonin regulates circadian sleep cycles.

Step-by-Step Solution

1
Identify the primary role of Calcitonin
Calcitonin is produced by the thyroid gland to lower elevated blood calcium levels.
It acts antagonistically to Parathyroid Hormone (PTH) to regulate plasma calcium homeostasis.
2
Determine the function of Vasopressin (ADH)
Vasopressin increases water permeability in the collecting ducts of the nephron.
This reduces urinary water loss and increases blood volume.
3
Analyze the action of Oxytocin
Oxytocin triggers uterine smooth muscle contractions and myoepithelial cell contraction in lactating glands.
It facilitates parturition and the milk let-down reflex.
4
Recall the secretion source and action of Melatonin
Melatonin is produced by the pineal gland to control diurnal rhythms.
Synthesis increases in darkness to signal sleep readiness.

Key Concept

Endocrine Hormones and Physiological Regulation
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