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General Science and Technology

222 questions

All types222Multiple choice117Multiple select40True / False8Matching44Ordering13
Question 121Question →

Consider everyday applications and principles of wave physics and acoustics. Which of the following statements are correct?

Select all that apply

Show answer & explanation

Answer: Ultrasonic waves are widely utilized in medical sonography because their short wavelength allows high spatial resolution for imaging soft tissues.; SONAR (Sound Navigation and Ranging) technology relies on the reflection of ultrasonic acoustic pulses to determine the distance and depth of submerged objects.

Answer

The correct statements are that ultrasonic waves are utilized in medical sonography due to their short wavelength yielding high spatial resolution, and SONAR technology relies on the reflection of ultrasonic acoustic pulses to measure underwater distances.
Ultrasonic medical imaging relies on short wavelengths for high spatial resolution, and SONAR relies on acoustic reflection to calculate depth. Both statements accurately describe sound wave phenomena.

Step-by-Step Solution

1
Analyze the sound resolution characteristics of ultrasonic waves
Since wave speed v=fλv = f \lambda, higher frequency ff corresponds to smaller wavelength λ\lambda. Smaller wavelengths experience less diffraction around small objects, providing high-resolution images in medical ultrasound.
Resolving power increases as the wavelength of the probing wave decreases.
2
Evaluate the mechanism behind the Doppler Effect
Relative motion between source and observer changes the arrival rate of wave fronts, causing an apparent frequency shift f′=f(vv−vs)f' = f \left(\frac{v}{v - v_s}\right). The intrinsic source frequency ff remains constant.
Distinguishing between emitted source frequency and observed relative frequency is critical for Doppler analysis.
3
Examine SONAR operating principles and reverberation physics
SONAR uses echo timing of reflected ultrasound pulses (d=v⋅t2d = \frac{v \cdot t}{2}). Reverberation stems from multiple specular and diffuse reflections off boundaries, whereas porous absorbent materials damp reverberation.
Acoustic reflection enables distance measurement in SONAR, while reflection persistence causes reverberation.

Key Concept

Ultrasonic wave applications, Doppler effect mechanism, and acoustic reflection
Question 122Question →

Plant growth regulators play a crucial role in agricultural practices and plant development. Which of the following plant hormones is primarily responsible for promoting fruit ripening?

Show answer & explanation

Answer: Ethylene

Answer

Ethylene is the plant hormone primarily responsible for promoting fruit ripening.
Ethylene is a hydrocarbon gas acting as a natural plant hormone that accelerates cellular respiration, starch-to-sugar conversion, and tissue softening associated with fruit ripening.

Step-by-Step Solution

1
Identify the primary physiological function required by the question.
The requirement is to identify the hormone responsible for fruit ripening.
Different plant hormones regulate distinct physiological and developmental processes.
2
Evaluate the functions of major plant hormones.
Ethylene functions as a gaseous regulator that hastens respiration and fruit ripening (climacteric ripening). Auxins handle tropisms and apical dominance, gibberellins promote seed germination and stem growth, and abscisic acid mediates stress responses and dormancy.
Matching each hormone to its primary role distinguishes ripening regulators from growth or stress regulators.

Key Concept

Plant Hormones and Fruit Ripening Regulation
Estimated Time:45s
Question 123Question →

Match the water-soluble vitamins listed in List-I with their characteristic deficiency pathologies described in List-II:

Click a left item, then click its matching right item

Items

Vitamin B1 (Thiamine)
Vitamin B3 (Niacin)
Vitamin B6 (Pyridoxine)
Vitamin B12 (Cobalamin)

Matches

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Answer

Vitamin B1 matches with Beriberi and Wernicke-Korsakoff syndrome; Vitamin B3 matches with Pellagra; Vitamin B6 matches with Sideroblastic anemia and peripheral neuropathy; Vitamin B12 matches with Pernicious anemia and subacute combined degeneration of the spinal cord.
Each water-soluble vitamin fulfills a distinct biochemical coenzymatic role. Thiamine (B1) is essential for oxidative decarboxylation in carbohydrate metabolism, preventing cardiac and neurological Beriberi. Niacin (B3) generates NAD/NADP for redox reactions, preventing Pellagra. Pyridoxine (B6) acts as a cofactor in transamination and heme formation, preventing sideroblastic anemia and neuropathy. Cobalamin (B12) is necessary for DNA maturation and myelin maintenance, preventing pernicious anemia and spinal cord degeneration.

Step-by-Step Solution

1
Analyze Vitamin B1 (Thiamine) function and deficiency state
Thiamine pyrophosphate (TPP) is critical for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase. Deficiency impairs ATP production, causing Beriberi and Wernicke-Korsakoff encephalopathy.
Identify the primary metabolic pathway affected by Thiamine impairment.
2
Analyze Vitamin B3 (Niacin) function and deficiency state
Niacin forms NAD+/NADP+. Its deficiency manifests as Pellagra, characterized by the 3 Ds: dermatitis, diarrhea, and dementia.
Identify the systemic organ systems affected by NAD depletion.
3
Analyze Vitamin B6 (Pyridoxine) function and deficiency state
Pyridoxal phosphate (PLP) is essential for neurotransmitter synthesis and delta-aminolevulinic acid (ALA) synthase in heme synthesis. Deficiency produces sideroblastic anemia and peripheral neuropathy.
Differentiate B6-dependent microcytic anemia from B12 macrocytic anemia.
4
Analyze Vitamin B12 (Cobalamin) function and deficiency state
Cobalamin is required for methionine synthase and methylmalonyl-CoA mutase. Lack of intrinsic factor leads to pernicious anemia (megaloblastic) and subacute combined degeneration of the spinal cord.
Establish the specific neuro-hematological link unique to Cobalamin deficiency.

Key Concept

Metabolic roles and pathological manifestations of B-complex vitamin deficiencies in human physiology
Question 124Question →

Which of the following human physiological systems is directly affected by the neurological toxin secreted during an infection by Clostridium tetani, leading to persistent skeletal muscle spasms?

Show answer & explanation

Answer: Blockade of inhibitory neurotransmitter release such as GABA and glycine in the central nervous system

Answer

Blockade of inhibitory neurotransmitter release such as GABA and glycine in the central nervous system
Tetanus is caused by the bacterium Clostridium tetani. Its exotoxin, tetanospasmin, selectively prevents the presynaptic release of inhibitory neurotransmitters (such as GABA and glycine) across spinal interneurons. Loss of inhibition leads to hyper-reflexia and violent muscle spasms.

Step-by-Step Solution

1
Identify the pathogen and its specific toxin mechanism
Clostridium tetani is an anaerobic bacterium that produces the potent neurotoxin tetanospasmin.
Understanding the pathogen category (bacterial exotoxin) helps distinguish tetanus from viral or protozoan neuromuscular disorders.
2
Analyze the physiological effect of tetanospasmin on neurotransmission
Tetanospasmin retrogradely travels to interneurons in the central nervous system and blocks the release of inhibitory neurotransmitters (glycine and GABA).
Without inhibitory signals, motor neurons fire uncontrollably, resulting in reflex spasms and lockjaw (spastic paralysis).

Key Concept

Tetanus Neurotoxic Pathology and Neuromuscular Physiology
Question 125Question →

Which of the following cellular organelles is primarily responsible for generating energy in the form of ATP during cellular respiration?

Show answer & explanation

Answer: Mitochondria

Answer

Mitochondria
Mitochondria are double-membrane organelles where aerobic respiration takes place, yielding ATP through oxidative phosphorylation.

Step-by-Step Solution

1
Identify the biological process mentioned in the stem.
The process described is cellular respiration and the synthesis of ATP (adenosine triphosphate).
Cellular respiration is the metabolic pathway that extracts chemical energy from nutrients.
2
Match the biological process to the corresponding cell organelle.
Mitochondria contain the enzymes for the Krebs cycle and the electron transport chain required to produce ATP.
Mitochondria act as the site of aerobic respiration in eukaryotic cells.

Key Concept

Function of Mitochondria in Cellular Respiration
Estimated Time:45s
Question 126Question →

Optical fibers are widely used in modern telecommunication networks and medical endoscopy to transmit light signals across long distances with minimal loss of intensity. Which optical phenomenon is primarily responsible for guiding light through the core of an optical fiber?

Show answer & explanation

Answer: Total internal reflection at the core-cladding boundary

Answer

Total internal reflection at the core-cladding boundary
Optical fibers operate on the principle of total internal reflection. The inner core has a higher refractive index than the surrounding cladding. When light signals enter the fiber at an appropriate angle, they repeatedly strike the core-cladding interface at an angle greater than the critical angle, reflecting entirely within the core with negligible signal loss.

Step-by-Step Solution

1
Identify the structural composition of an optical fiber
An optical fiber consists of an inner core with a higher refractive index (n1n_1) surrounded by an outer cladding with a lower refractive index (n2n_2).
Light transmission requires light to travel from a denser medium toward a rarer medium.
2
Determine the conditions for total internal reflection
When light inside the core hits the core-cladding boundary at an angle of incidence greater than the critical angle (θc=arcsin⁡(n2/n1)\theta_c = \arcsin(n_2/n_1)), no light refracts into the cladding.
100% of the light energy is reflected back into the core, allowing high-efficiency propagation over long distances.

Key Concept

Total Internal Reflection in Optical Fibers
Question 127Question →

Match the following key defense assets and nuclear energy installations in India (List-I) with their primary technological or operational features (List-II).

Click a left item, then click its matching right item

Items

Kakrapar Atomic Power Station Unit-3
Kamini Reactor
Prototype Fast Breeder Reactor (PFBR)
INS Arihant

Matches

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Answer

Kakrapar Unit-3 corresponds to the first indigenously designed 700 MWe Pressurised Heavy Water Reactor; Kamini Reactor corresponds to the research reactor using Uranium-233 fuel; Prototype Fast Breeder Reactor corresponds to the sodium-cooled Stage-2 reactor; and INS Arihant corresponds to the nuclear-powered ballistic missile submarine.
Kakrapar Unit-3 is the pioneer in India's 700 MWe PHWR series. Kamini operates on Uranium-233 at Kalpakkam. The Prototype Fast Breeder Reactor (PFBR) is the cornerstone of Stage-2 sodium-cooled breeder technology. INS Arihant provides India with a sea-based nuclear ballistic missile capability.

Step-by-Step Solution

1
Identify the classification of Kakrapar Unit-3.
It is India's flagship 700 MWe indigenous Pressurised Heavy Water Reactor.
Establishes the link between Kakrapar and 700 MWe PHWR technology.
2
Determine the fuel characteristic of the Kamini reactor.
Kamini uses Uranium-233 derived from Thorium irradiation.
Matches Kamini with its unique U-233 fuel cycle.
3
Identify the reactor type and stage of the Prototype Fast Breeder Reactor.
PFBR uses liquid sodium coolant to breed more fissile material in Stage-2.
Links PFBR with fast breeder reactor technology.
4
Analyze the strategic role of INS Arihant.
INS Arihant is a nuclear-powered submarine capable of launching ballistic missiles (SSBN).
Associates INS Arihant with naval strategic nuclear deterrence.

Key Concept

Classification of India's major defense installations and nuclear power/research reactor technologies.
Estimated Time:1m 30s
Question 128Question →

With reference to India's indigenously developed 'RudraM-1' defense missile system, consider the following statements:

1. It is India's first indigenous Next Generation Anti-Radiation Missile (NGARM) developed by DRDO to neutralize enemy radar and communication assets.
2. It employs a dual-thrust solid rocket motor for propulsion and features a Passive Homing Head for radiation source tracking.
3. It is designed to be launched exclusively from ground-based mobile launchers as part of the Ballistic Missile Defence (BMD) shield.

Which of the statements given above are correct?

Show answer & explanation

Answer: 1 and 2 only

Answer

1 and 2 only
The combination selecting 1 and 2 only is correct. RudraM-1 is DRDO's indigenously developed air-launched Next Generation Anti-Radiation Missile (NGARM). It uses a dual-thrust solid propellant rocket motor and a passive homing head to destroy enemy communication and radar installations. It is integrated on Su-30MKI aircraft rather than ground-based BMD networks.

Step-by-Step Solution

1
Analyze Statement 1 regarding the basic classification and purpose of RudraM-1.
RudraM-1 is India's first indigenously developed air-to-surface Next Generation Anti-Radiation Missile (NGARM) designed by DRDO to target enemy air defense radars, tracking stations, and communication nodes. Statement 1 is correct.
Establishing primary operational role of the missile.
2
Analyze Statement 2 regarding propulsion and guidance mechanism.
RudraM-1 utilizes a dual-thrust solid rocket motor for propulsion and incorporates a Passive Homing Head (PHH) capable of detecting and homing in on radio frequency emission sources over a wide band. Statement 2 is correct.
Verifying technical and propulsion specifications.
3
Analyze Statement 3 regarding deployment platform.
RudraM-1 is an air-launched missile integrated with Indian Air Force fighter aircraft (such as Su-30MKI), not a ground-based missile defense interceptor. Statement 3 is incorrect.
Differentiating air-launched tactical weapons from ground-based strategic defense systems.

Key Concept

Classification, guidance technology, and platform integration of India's indigenously developed anti-radiation missile (RudraM-1).
Estimated Time:1m 30s
Question 129Question →

In public-key cryptography (asymmetric encryption), when a sender wants to transmit a confidential message securely to a specific recipient, which of the following keys must be used by the sender to encrypt the message?

Show answer & explanation

Answer: Recipient's public key

Answer

The recipient's public key must be used by the sender to encrypt the message for confidentiality.
In asymmetric cryptography, each participant has a public key and a private key. To send a confidential message, the sender encrypts the plaintext using the recipient's public key. Because the recipient is the sole possessor of the corresponding private key, only they can decrypt and read the original message.

Step-by-Step Solution

1
Identify the key structure of asymmetric cryptography.
Asymmetric cryptography utilizes a mathematically linked pair of keys for every user: a public key (shared openly) and a private key (kept secret).
Understanding the distinction between public and private keys is fundamental to asymmetric systems.
2
Determine which key achieves confidentiality for a specific recipient.
Encrypting data with a user's public key ensures that the data can only be decrypted by the matching private key owned uniquely by that recipient.
This mathematical pairing enables secure key distribution and message secrecy across untrusted networks.

Key Concept

Public Key Cryptography (Asymmetric Encryption)
Estimated Time:45s
Question 130Question →

Regarding the chemical characteristics and functions of industrial and household chemical agents, which of the following statements are correct?

Select all that apply

Show answer & explanation

Answer: Aspartame decomposes at elevated cooking temperatures, restricting its utility as an artificial sweetener primarily to cold foods and unheated beverages.; Vulcanization of natural rubber involves heating crude polyisoprene with elemental sulfur to form inter-chain disulfide cross-links, enhancing mechanical strength and thermal stability.; Anionic detergents feature long hydrophobic hydrocarbon chains connected to hydrophilic sulfonate or sulfate groups where the surface-active portion carries a net negative charge.

Answer

The statements asserting that aspartame decomposes at elevated cooking temperatures, vulcanization improves natural rubber through sulfur cross-linking, and anionic detergents feature negatively charged surface-active hydrophobic sulfonate groups are correct. The statement regarding Butylated Hydroxytoluene (BHT) is incorrect because BHT acts as a free-radical scavenger to prevent fat oxidation rather than promoting radical formation.
The correct statements accurately state the thermal instability of aspartame, the cross-linking function of sulfur in rubber vulcanization, and the ionic charge structure of anionic synthetic detergents. Aspartame decomposes when heated due to peptide hydrolysis; sulfur bridges anchor polyisoprene chains during vulcanization; and anionic detergents derive their surfactant action from negatively charged polar heads.

Step-by-Step Solution

1
Evaluate the chemical stability of aspartame under heat.
Aspartame degrades at elevated cooking temperatures due to peptide bond breakdown, making it suitable only for cold foods and beverages.
Peptides undergo thermal decomposition and hydrolysis, leading to loss of sweetness.
2
Analyze the chemical mechanism and structural changes in rubber vulcanization.
Heating cis-1,4-polyisoprene with sulfur introduces sulfur bridge cross-links between polymer chains, upgrading elasticity, tensile strength, and thermal resilience.
Cross-linking restricts chain sliding while allowing reversible elastic recovery.
3
Assess the structural classification of synthetic anionic detergents.
Anionic detergents dissociate in aqueous solutions to yield surfactant anions with long-chain hydrophobic groups attached to sulfate or sulfonate anions.
The active detergent ion responsible for micelle formation and cleansing carries a negative charge.
4
Examine the preservative mechanism of Butylated Hydroxytoluene (BHT).
BHT functions as a radical scavenger (antioxidant) that inhibits lipid peroxidation rather than promoting free-radical oxidative decay.
Hindered phenols donate hydrogen to peroxy radicals, forming stable non-radical products.

Key Concept

Chemical principles governing artificial sweeteners, synthetic detergents, polymer vulcanization, and food antioxidants.
Question 131Question →

Regarding the structural characteristics of prokaryotic and eukaryotic cells, which of the following statements are correct?

Select all that apply

Show answer & explanation

Answer: Prokaryotic cells lack membrane-bound organelles such as the nucleus, mitochondria, and endoplasmic reticulum.; Prokaryotic genetic material is typically organized as a single circular double-stranded DNA molecule located in the nucleoid region.

Answer

The correct statements are that prokaryotic cells lack membrane-bound organelles such as the nucleus and mitochondria, and their genetic material is typically organized as a single circular double-stranded DNA molecule located in the nucleoid region.
Prokaryotic cells are characterized by the absence of membrane-bound organelles and a true nucleus. Their genetic material is located in a nucleoid region as a circular double-stranded DNA molecule.

Step-by-Step Solution

1
Analyze organelle structure in prokaryotes
Prokaryotes lack membrane-bound internal compartments including a true nucleus, mitochondria, and endoplasmic reticulum.
This is a defining biological distinction between prokaryotes and eukaryotes.
2
Evaluate ribosome size differences
Prokaryotes possess 70S ribosomes, while eukaryotes possess 80S ribosomes in their cytoplasm.
Ribosomal sedimentation coefficient differs between the two domains of life.
3
Examine nuclear material organization
Prokaryotic DNA is non-enclosed, naked circular double-stranded DNA present in the nucleoid.
Linear DNA in a membrane-bound nucleus is unique to eukaryotes.
4
Verify cell wall composition
Bacterial cell walls consist of peptidoglycan, whereas plant cell walls consist of cellulose.
Cell wall chemical compositions vary distinctly between kingdoms.

Key Concept

Structural differences between prokaryotic and eukaryotic cells
Question 132Question →

Arrange the following key institutional and strategic milestones in India's defense and nuclear technology establishment in chronological order from earliest to latest:

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological sequence from earliest to latest is: Establishment of the Atomic Energy Commission (AEC) (1948) → Formation of the Department of Atomic Energy (DAE) (1954) → Formation of the Defence Research and Development Organisation (DRDO) (1958) → Formal sanction of the Integrated Guided Missile Development Programme (IGMDP) (1983) → Official operationalization and public release of India's Nuclear Doctrine by the Cabinet Committee on Security (2003).
The correct chronological sequence begins with the Atomic Energy Commission (AEC) established in August 1948, followed by the executive Department of Atomic Energy (DAE) in August 1954. Next, the Defence Research and Development Organisation (DRDO) was established in 1958. The Integrated Guided Missile Development Programme (IGMDP) was formally launched in July 1983. Finally, India's Nuclear Doctrine was officially released by the Cabinet Committee on Security in January 2003.

Step-by-Step Solution

1
Identify the founding year of the Atomic Energy Commission (AEC).
AEC was established in August 1948.
It was the initial policy and apex body set up shortly after independence.
2
Identify the creation date of the Department of Atomic Energy (DAE).
DAE was established in August 1954.
DAE was established six years after AEC to provide executive administrative architecture directly under the Prime Minister.
3
Identify the founding year of the Defence Research and Development Organisation (DRDO).
DRDO was formed in 1958.
It amalgamated existing defense technical establishments and the Defence Science Organisation.
4
Identify the year when IGMDP was launched.
IGMDP was sanctioned in July 1983.
It led to the development of the Agni, Prithvi, Akash, Trishul, and Nag missile systems.
5
Identify the year when India's formal Nuclear Doctrine was publicly released by the Cabinet Committee on Security.
The doctrine was officially operationalized and released in January 2003.
Following the 1998 Pokhran-II tests, the doctrine finalized key principles such as No First Use and Credible Minimum Deterrence.

Key Concept

Chronological evolution of Indian institutional frameworks and strategic policy in Defense and Nuclear Technology.
Question 133Question →

During sunrise and sunset, the Sun appears distinctly reddish when viewed from the Earth's surface. Which optical phenomenon is primarily responsible for this color phenomenon?

Show answer & explanation

Answer: Rayleigh scattering of light by atmospheric molecules, where shorter wavelengths are scattered away more than longer wavelengths

Answer

Rayleigh scattering of light by atmospheric molecules, where shorter wavelengths are scattered away more than longer wavelengths
During sunrise and sunset, sunlight travels through a longer path in the Earth's atmosphere. According to Rayleigh's law, the scattering of light is inversely proportional to the fourth power of its wavelength. Consequently, shorter wavelengths such as blue and violet are scattered in all directions and lost from the direct line of sight, while longer wavelengths such as red pass through with minimal scattering and reach the observer's eyes.

Step-by-Step Solution

1
Analyze the path length of sunlight through the Earth's atmosphere during sunrise and sunset.
Near the horizon, sunlight travels a significantly longer path through atmospheric layers than at noon.
The slant angle requires light to pass through more air mass and scattering centers.
2
Apply Rayleigh's law of scattering.
Scattering intensity is inversely proportional to the fourth power of wavelength (I∝1λ4I \propto \frac{1}{\lambda^4}).
Shorter wavelengths (blue and violet) are scattered much more strongly than longer wavelengths (red and orange).
3
Determine which wavelengths reach the observer.
Blue light is scattered out in all directions, while unscattered red light passes directly to the observer.
Red light has a longer wavelength and undergoes minimal scattering over the long atmospheric path.

Key Concept

Rayleigh Scattering of Light
Estimated Time:1m 0s
Question 134Question →

In the study of human health, communicable diseases are classified by their causative pathogens and mode of transmission. Which of the following statements regarding infectious human diseases are correct?

Select all that apply

Show answer & explanation

Answer: Dengue fever and Zika virus infection are both viral diseases transmitted to humans primarily through the bite of infected Aedes mosquitoes.; African trypanosomiasis (sleeping sickness) is caused by a protozoan parasite and is transmitted through the bite of infected tsetse flies.

Answer

The correct statements are: (1) Dengue fever and Zika virus infection are viral diseases transmitted via Aedes mosquitoes, and (2) African trypanosomiasis is a protozoan disease transmitted by tsetse flies.
The statements confirming that Dengue and Zika are viral infections transmitted by Aedes mosquitoes, and that African trypanosomiasis is a protozoan disease transmitted by tsetse flies, are scientifically accurate.

Step-by-Step Solution

1
Evaluate statement regarding Dengue and Zika viruses
Dengue and Zika are both arboviruses (flaviviruses) transmitted by female Aedes mosquitoes (Aedes aegypti and Aedes albopictus). The statement is correct.
Accurate pathogen and vector classification.
2
Evaluate statement regarding African trypanosomiasis
Sleeping sickness is caused by protozoan parasites of the genus Trypanosoma and transmitted by tsetse flies. The statement is correct.
Correct identification of protozoan etiology and insect vector.
3
Evaluate statement regarding Trachoma
Trachoma is caused by the bacterium Chlamydia trachomatis, not a virus, and spreads via direct contact and flies rather than contaminated water. The statement is incorrect.
Conflating bacterial pathogen with viral etiology.
4
Evaluate statement regarding Malaria
Malaria is caused by Plasmodium protozoa (not bacteria) and transmitted by female Anopheles mosquitoes (male mosquitoes feed on plant nectar). The statement is incorrect.
Misidentifying pathogen group and mosquito vector sex.

Key Concept

Classification of infectious human diseases by pathogen type (viral, bacterial, protozoan) and vector transmission mechanism.
Question 135Question →

Consider the following statements regarding human infectious diseases, their causative pathogens, and biological vectors:

1. Japanese Encephalitis is a viral infection caused by a flavivirus and is primarily transmitted to humans via infected *Culex* mosquitoes.
2. Lyme disease is a protozoan infection caused by *Plasmodium* species and is transmitted through the bite of hard-bodied *Ixodes* ticks.
3. Lymphatic Filariasis is a parasitic disease caused by filarial nematodes such as *Wuchereria bancrofti* and is transmitted by mosquito vectors.

Which of the statements given above is/are correct?

Show answer & explanation

Answer: 1 and 3 only

Answer

The correct option is 1 and 3 only.
The option stating '1 and 3 only' is correct because Japanese Encephalitis is indeed a flaviviral infection transmitted by Culex mosquitoes, and Lymphatic Filariasis is caused by filarial nematodes (Wuchereria bancrofti) transmitted via mosquitoes. Statement 2 is false because Lyme disease is a bacterial infection caused by Borrelia burgdorferi, not a protozoan infection caused by Plasmodium.

Step-by-Step Solution

1
Evaluate Statement 1 regarding Japanese Encephalitis etiology and vector
Statement 1 is correct. Japanese Encephalitis (JE) is caused by the Japanese encephalitis virus (a mosquito-borne flavivirus) and transmitted primarily by Culex mosquitoes, particularly Culex tritaeniorhynchus.
JE is an established viral zoonotic encephalitis endemic to parts of Asia.
2
Evaluate Statement 2 regarding Lyme disease pathogen classification
Statement 2 is incorrect. Lyme disease is caused by the spirochete bacterium Borrelia burgdorferi (and related bacterial species), not a protozoan parasite like Plasmodium (which causes malaria).
Confusing bacterial spirochetes with protozoans represents a fundamental pathogen mismatch.
3
Evaluate Statement 3 regarding Lymphatic Filariasis causative organism
Statement 3 is correct. Lymphatic Filariasis (commonly known as elephantiasis) is caused by microscopic, thread-like parasitic filarial nematodes (roundworms) including Wuchereria bancrofti, Brugia malayi, and Brugia timori, transmitted by Culex, Anopheles, and Aedes mosquitoes.
Filarial worms are helminths/nematodes that inhabit the human lymphatic system.

Key Concept

Classification of human infectious diseases by pathogen type (viral, bacterial, nematode, protozoan) and their biological transmission vectors.
Estimated Time:2m 0s
Question 136Question →

With reference to industrial chemical agents and cleansing compounds used in daily life, consider the following statements:

1. Calcium hypochlorite (CaOCl2CaOCl_2), commonly known as bleaching powder, acts as a bleaching agent primarily due to the liberation of nascent oxygen upon reaction with dilute acids or atmospheric carbon dioxide.
2. Hard water reduces the cleansing efficiency of soaps by reacting with sodium or potassium salts of fatty acids to form insoluble calcium and magnesium precipitates.
3. Synthetic detergents containing highly branched-chain alkyl benzene sulfonates are readily biodegradable by microorganisms compared to linear alkyl chain detergents.

Which of the statements given above is/are correct?

Show answer & explanation

Answer: 1 and 2 only

Answer

The correct option is the one stating that statements 1 and 2 only are correct.
Statements 1 and 2 accurately describe fundamental chemical processes: bleaching powder releases nascent oxygen which acts as a powerful oxidizing bleach, and hard water containing dissolved calcium and magnesium ions precipitates fatty acid salts of soaps. Statement 3 is false because highly branched alkyl chains resist microbial breakdown, whereas straight/linear alkyl chain detergents are readily biodegradable.

Step-by-Step Solution

1
Analyze statement 1 regarding bleaching powder mechanism
Bleaching powder (CaOCl2CaOCl_2) reacts with dilute acid or atmospheric CO2CO_2 to release hypochlorous acid (HOClHOCl), which decomposes to liberate nascent oxygen ([O][O]). The nascent oxygen oxidizes colored organic matter into colorless compounds. Thus, statement 1 is correct.
Bleaching action of chlorine-based bleaches depends on oxidation via nascent oxygen.
2
Analyze statement 2 regarding soap behavior in hard water
Hard water contains soluble Ca2+Ca^{2+} and Mg2+Mg^{2+} ions. When soap (sodium/potassium salts of fatty acids, e.g., RCOONaRCOONa) is added, it forms insoluble calcium and magnesium carboxylates (scum scum ), removing soap molecules from solution and hindering micelle formation. Thus, statement 2 is correct.
Precipitation of fatty acid salts depletes active surfactant molecules.
3
Analyze statement 3 regarding synthetic detergent structure and biodegradability
Detergents with highly branched alkyl chains cannot be degraded easily by sewage bacteria, leading to persistent foaming and water pollution. Linear alkylbenzene sulfonates (LAS) are straight-chain compounds easily broken down by microorganisms. Therefore, branched-chain detergents are less biodegradable than linear-chain detergents, making statement 3 incorrect.
Steric hindrance from alkyl branching prevents microbial enzymatic breakdown.

Key Concept

Chemical mechanisms of bleaching agents, soap-hard water interactions, and environmental biodegradability of surfactant hydrocarbon chain structures.
Question 137Question →

Which of the following statements regarding common cybersecurity threats and security mechanisms are correct?

Select all that apply

Show answer & explanation

Answer: Phishing is a social engineering attack where deceptive messages are used to trick individuals into revealing sensitive credentials or information.; Ransomware is malicious software designed to block access to data or systems, typically by encrypting files, until a ransom is paid.

Answer

The statements defining Phishing as a deceptive credential-harvesting attack and Ransomware as file-encrypting extortion malware are correct.
The correct statements correctly describe social engineering (phishing) and extortion malware (ransomware). Both represent foundational concepts in information security awareness.

Step-by-Step Solution

1
Evaluate the definition of Phishing.
Confirmed correct. Phishing uses fraudulent communications (emails, websites) to trick targets into providing sensitive information.
Matches the fundamental definition of social engineering in information security.
2
Evaluate the definition of Ransomware.
Confirmed correct. Ransomware locks or encrypts system resources to extort payment from victims.
Matches standard cybersecurity classification of malware behaviors.
3
Evaluate the description of a Firewall.
Confirmed incorrect. Firewalls inspect traffic according to defined rules (allowing legitimate traffic and blocking unauthorized traffic), not blocking everything blindly.
Misinterprets network security filtering mechanisms.
4
Evaluate the statement regarding Symmetric Cryptography.
Confirmed incorrect. Dual public/private keys are used in asymmetric (public-key) cryptography, not symmetric cryptography.
Confuses symmetric and asymmetric cryptographic key structures.

Key Concept

Basic Cybersecurity Threat Vector Definitions and Security Controls
Question 138Question →

With reference to modern agricultural techniques, consider the following statements regarding 'Fertigation':
1. Fertigation is the application of water-soluble fertilizers to crops through an irrigation system.
2. It significantly reduces nutrient leaching into groundwater compared to conventional broadcast fertilizer application.

Which of the statements given above is/are correct?

Show answer & explanation

Answer: Both 1 and 2

Answer

Both 1 and 2 are correct.
Fertigation is the method of applying fertilizers through an irrigation system (most commonly micro-irrigation or drip irrigation). By spoon-feeding water-soluble nutrients directly to the root zone at required times, it minimizes nutrient losses caused by leaching, volatilization, and surface runoff.

Step-by-Step Solution

1
Define Fertigation
Fertigation combines fertilization and irrigation by injecting liquid or soluble fertilizers directly into the drip or micro-irrigation network.
To verify the accuracy of the first statement.
2
Analyze Environmental and Efficiency Impacts
Because nutrients are supplied directly to the active root zone in controlled quantities, fertilizer efficiency increases and runoff/leaching into groundwater is minimized.
To verify the accuracy of the second statement.

Key Concept

Fertigation Principles and Micro-Irrigation Benefits
Question 139Question →

Regarding the Air-Independent Propulsion (AIP) system indigenously developed for India's conventional submarine fleet, which of the following statements are correct?

Select all that apply

Show answer & explanation

Answer: The AIP system developed by DRDO's Naval Materials Research Laboratory (NMRL) is based on Phosphoric Acid Fuel Cell (PAFC) technology using hydrogen generated on-board.; The fuel-cell based AIP module generates electric power electrochemically by combining hydrogen and oxygen, producing pure water as its primary byproduct.

Answer

The correct statements are the ones highlighting that NMRL's indigenous AIP system utilizes Phosphoric Acid Fuel Cell (PAFC) technology with on-board hydrogen generation, and that fuel cell AIP modules produce electrical power electrochemically with pure water as the main byproduct without requiring daily surfacing.
The correct statements accurately identify that DRDO-NMRL developed a Phosphoric Acid Fuel Cell (PAFC) based AIP system that generates hydrogen on-board. Furthermore, fuel cell AIP technology produces electrical energy by combining stored oxygen and generated hydrogen, yielding pure water as a byproduct while drastically reducing indiscretion rates (time spent at snort depth).

Step-by-Step Solution

1
Analyze the technological mechanism of India's indigenous AIP system
DRDO's Naval Materials Research Laboratory (NMRL) developed a fuel-cell based Air-Independent Propulsion system relying on Phosphoric Acid Fuel Cell (PAFC) technology with on-demand hydrogen generation from sodium borohydride.
Fuel cells are significantly quieter and more efficient than closed-cycle diesel or Stirling engine alternatives for conventional submarines.
2
Evaluate the operational role and endurance impact of AIP on conventional submarines
AIP allows diesel-electric submarines to remain submerged for up to 14 days without snorting (using a snorkel to draw air for diesel generators), eliminating the need for daily battery-recharging surfaces.
Snorting exposes submarines to radar detection; AIP minimizes vulnerability by eliminating frequent snorting cycles.
3
Distinguish between conventional AIP-fitted submarines and nuclear-powered submarines
AIP is an upgrade for conventional diesel-electric submarines (like the Kalvari-class/P-75), whereas nuclear submarines (SSNs/SSBNs like INS Arihant) draw power from nuclear fission reactors and do not need AIP modules.
Nuclear reactors provide near-indefinite power without atmospheric air; AIP is a technological bridge for non-nuclear vessels.

Key Concept

Submarine Air-Independent Propulsion (AIP) Technology and Fuel Cell Systems
Estimated Time:2m 0s
Question 140Question →

With reference to plant defense mechanisms and biological crop protection technologies against biotic stresses, consider the following statements:

1. Systemic Acquired Resistance (SAR) is triggered predominantly by biotrophic pathogens and depends on salicylic acid signaling to induce systemic expression of pathogenesis-related (PR) genes.
2. Induced Systemic Resistance (ISR) is typically elicited by non-pathogenic plant growth-promoting rhizobacteria (PGPR) and operates via jasmonic acid and ethylene signaling pathways.
3. Root colonization by beneficial PGPR during ISR activation causes localized hypersensitive tissue necrosis at the site of interaction.

Which of the statements given above are correct?

Show answer & explanation

Answer: 1 and 2 only

Answer

Statements 1 and 2 only are correct.
The option stating '1 and 2 only' is correct because Systemic Acquired Resistance (SAR) relies on salicylic acid signaling to induce pathogenesis-related gene expression following biotrophic pathogen attack, whereas Induced Systemic Resistance (ISR) is triggered by beneficial rhizobacteria through jasmonic acid and ethylene pathways. Beneficial rhizobacteria colonize root surfaces without eliciting hypersensitive cell necrosis.

Step-by-Step Solution

1
Analyze Statement 1 regarding Systemic Acquired Resistance (SAR)
SAR is an induced defense mechanism activated primarily by biotrophic or hemi-biotrophic pathogens. It relies on the accumulation of endogenous salicylic acid (SA) and leads to systemic transcriptomic activation of pathogenesis-related (PR) proteins (such as PR-1, PR-2, and PR-5). Thus, Statement 1 is correct.
Salicylic acid serves as the crucial phytohormone signal for broad-spectrum systemic resistance against biotrophic pathogens.
2
Analyze Statement 2 regarding Induced Systemic Resistance (ISR)
ISR is elicited by root-colonizing beneficial microbes, particularly plant growth-promoting rhizobacteria (PGPR) like Pseudomonas fluorescens species. Unlike SAR, ISR does not require salicylic acid hyper-accumulation or PR protein expression; instead, it relies on intact responsiveness to jasmonic acid (JA) and ethylene (ET). Thus, Statement 2 is correct.
ISR functions via a primed state mediated by jasmonate and ethylene pathways without inducing constitutive antimicrobial protein expression prior to actual pathogen challenge.
3
Analyze Statement 3 regarding root interaction and hypersensitive response
Hypersensitive response (HR) involves localized programmed cell death (necrosis) to restrict avirulent biotrophic pathogens. Beneficial PGPR colonize the rhizosphere and root cortex symbiotically without triggering HR or tissue necrosis. Thus, Statement 3 is incorrect.
PGPR root colonization is non-pathogenic and establishes a beneficial interaction without causing localized host cell destruction.

Key Concept

Distinct biochemical pathways of plant immune responses: Systemic Acquired Resistance (SAR) vs Induced Systemic Resistance (ISR)
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