Q. With reference to ‘fly ash’ produced by the power plants using coal as fuel, which of the following statements is/are correct?

  1. Fly ash can be used in the production of bricks for building construction.
  2. Fly ash can be used as a replacement for some of the Portland cement contents of concrete.
  3. Fly ash is made up of silicon dioxide and calcium oxide only, and does not contain any toxic elements.

Select the correct answer using the code given below.

(a) 1 and 2
(b) 2 only
(c) 1 and 3
(d) 3 only

Answer: (a) 1 and 2

Fly Ash
  • Fly ash is an unwanted unburnt residue of coal combustion in a coal thermal power plant.
  • It is emitted along with flue gases during the burning of coal in a furnace and collected using the electrostatic precipitators.
  • The fly ash collected with the help of precipitators is converted into a wet slurry to minimise fugitive dust emissions.
  • It is then transported to the scientifically designed ash ponds through slurry pipelines.
  • Composition:
    • Composition of fly ash depends upon the composition of coal being burnt. It may contain Beryllium, Arsenic, unburnt Carbon, Silicon Oxides, Dioxins, aluminium oxide, ferric oxide, calcium oxide, etc.
      • These elements are severe environmental pollutants.
  • Properties:
    • Resemble Portland cement but is chemically different.
      • Portland cement is a binding material in the form of a finely ground powder that is manufactured by burning and grinding a mixture of limestone and clay.
      • Its chemical composition includes calcium silicates, calcium aluminate and calcium aluminoferrite.
    • Exhibit cementitious properties.
      • A cementitious material is one that hardens when mixed with water.
  • Uses: It is used in concrete and cement products, road base, metal recovery, and mineral filler among others.
  • Harmful Effects: Fly ash particles are toxic air pollutants. They can trigger heart disease, cancer, respiratory diseases and stroke.
    • When combined with water they cause leaching of heavy metals in ground water.
    • It also pollutes the soil, and affects the root development system of trees.
    • Gross under-utilisation of this by-product over the years has led to the accumulation of 1,670 million tonnes of fly ash according to the Summary of Ash Generation and Utilisation during 2020-2021 by the Joint Committee earlier constituted by the NGT.
  • Related Initiatives:
    • Earlier in 2021, National Thermal Power Corporation (NTPC) Limited had invited Expression of Interest (EOI) for sale of fly ash.
    • NTPC has also collaborated with Cement manufacturers around the country to supply Fly Ash.
    • Pradhan Mantri Awas Yojana (Urban) has focused on new construction technologies such as using fly ash bricks that are innovative, and environmentally friendly.
      • Even state governments have come out with their Fly ash utilisation policies, e.g., Maharashtra was the first state to adopt the policy.
    • A web portal for monitoring of fly ash generation and utilisation and a mobile based application titled “ASHTRACK” has been launched by the Government.
    • Goods and Services Tax (GST) rates on fly ash and its products have been reduced to 5%.

Q. In the context of modern scientific research, consider the following statements about ‘lceCube’, a particle detector located at South Pole, which was recently in the news:

  1. It is the world’s largest neutrino detector, encompassing a cubic kilometre of ice.
  2. It is a powerful telescope to search for dark matter.
  3. It is buries deep in the ice.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (d) 1, 2 and 3

IceCube Neutrino Observatory
  • The IceCube Neutrino Observatory (or simply IceCube) is a neutrino observatory constructed at the Amundsen–Scott South Pole Station in Antarctica. The project is a recognized CERN experiment (RE10). Its thousands of sensors are located under the Antarctic ice, distributed over a cubic kilometre.
  • Similar to its predecessor, the Antarctic Muon And Neutrino Detector Array (AMANDA), IceCube consists of spherical optical sensors called Digital Optical Modules (DOMs), each with a photomultiplier tube (PMT) and a single-board data acquisition computer which sends digital data to the counting house on the surface above the array. IceCube was completed on 18 December 2010.
  • DOMs are deployed on strings of 60 modules each at depths between 1,450 and 2,450 meters into holes melted in the ice using a hot water drill. IceCube is designed to look for point sources of neutrinos in the teraelectronvolt (TeV) range to explore the highest-energy astrophysical processes.
  • IceCube is part of a series of projects developed and supervised by the University of Wisconsin–Madison.
  • The Antarctic neutrino observatory, which also includes the surface array IceTop and the dense infill array DeepCore, was designed as a multipurpose experiment.
  • IceCube collaborators address several big questions in physics, like the nature of dark matter and the properties of the neutrino itself.
  • IceCube also observes cosmic rays that interact with the Earth’s atmosphere, which have revealed fascinating structures that are not presently understood.
  • Exciting new research conducted by the collaboration is opening a new window for exploring our universe.

Q. The term ‘Goldilocks Zone’ is often seen news in the context of

(a) the limits of habitable zone above the surface of the Earth

(b) regions inside the Earth where shale gas is available

(c) search for the Earth-like planets in outer space

(d) search for meteorites containing precious metals

Answer: (c) search for the Earth-like planets in outer space

Goldilocks Zone
  • A habitable zone, also called the “Goldilocks zone”, is the area around a star where it is not too hot and not too cold for liquid water to exist on the surface of surrounding planets.
  • Our Earth is in the Sun’s Goldilocks zone. If Earth were where the dwarf planet Pluto is, all its water would freeze; on the other hand, if Earth were where Mercury is, all its water would boil off.
  • Life on Earth started in water, and water is a necessary ingredient for life as we know it.
  • So, when scientists search for the possibility of alien life, any rocky exoplanet in the habitable zone of its star is an exciting find.

Q. With reference to ‘fuel cells’ in which hydrogen-rich fuel and oxygen are used to generate electricity, consider the following statements:

  1. If pure hydrogen is used as a fuel, the fuel cell emits heat and water as by-products.
  2. Fuel cells can be used for powering buildings and not for small devices like laptop computers.
  3. Fuel cells produce electricity in the form of Alternating Current (AC).

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (a) 1 only

  • A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions.
  • Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from substances that are already present in the battery. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.
  • Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. They are also used to power fuel cell vehicles, including forklifts, automobiles, buses, trains, boats, motorcycles, and submarines.
  • There are many types of fuel cells, but they all consist of an anode, a cathode, and an electrolyte that allows ions, often positively charged hydrogen ions (protons), to move between the two sides of the fuel cell. At the anode, a catalyst causes the fuel to undergo oxidation reactions that generate ions (often positively charged hydrogen ions) and electrons. The ions move from the anode to the cathode through the electrolyte. At the same time, electrons flow from the anode to the cathode through an external circuit, producing direct current electricity. At the cathode, another catalyst causes ions, electrons, and oxygen to react, forming water and possibly other products.

Q. In which of the following activities are Indian Remote Sensing (IRS) satellites used?

  1. Assessment of crop productivity
  2. Locating groundwater resources
  3. Mineral exploration
  4. Telecommunications
  5. Traffic studies

Select the correct answer using the codes given below.

(a) 1, 2 and 3 only
(b) 4 and 5 only
(c) 1 and 2 only
(d) 1, 2, 3, 4 and 5

Answer: (a) 1, 2 and 3 only

IRS Satellite System
  • Indian Remote sensing satellites are spacecraft outfitted with sensors that can capture images and data from space of the Earth.
  • These sensors are capable of detecting different types of radiation emitted or reflected from the earth’s surface.
  • Remote sensing satellites are used for a variety of purposes, including weather monitoring, natural disaster monitoring, agriculture, forestry, and other land-based activities.
  • The launch of India’s first civilian IRS-1A spacecraft in March 1988 marked the start of a successful journey for the Indian Space Programme.
  • The National Natural Resources Management System (NNRMS) governs Indian Earth Observation activities.
  • The Indian Earth Observation (EO) system has been providing operational services to the user community with a slew of payloads in the thematic series of Indian Remote Sensing Satellites (IRS) and the INSAT systems.
  • The Indian Remote Sensing Satellite System operates one of the world’s largest constellations of remote sensing satellites.
  • IRS satellites provide data at various spatial, spectral, and temporal resolutions.
  • The National Remote Sensing Centre (NRSC) serves as the hub for the distribution of remote sensing satellite data products in India and neighbouring countries.
  • NRSC has an earth station in Shadnagar, about 55 kilometres from Hyderabad, that receives data from nearly all modern remote sensing satellites.
  • Applications of IRS
    • Applications in Agriculture and Soil
      • Cropping pattern mapping;
      • Pre- harvest crop area, production and yield estimation;
      • Condition assessment;
      • Monitoring command areas;
      • Compliance monitoring (farming practices) e.g. crop stubble burning;
      • Identification of suitable sites for different agricultural practices;
      • Mapping of soil characteristics;
      • Mapping of soil management practices;
      • Mapping of saline soils and monitoring of land reclamation;
      • Inventorying and categorization of wastelands; and
      • Identification of fishery prospects.
    • Applications in Bio-resources and Environment
      • Mapping of forest cover, types, density and species inventory;
      • Measurement of biophysical conditions of forest strands;
      • Social forestry and agroforestry mapping;
      • Biomass estimation;
      • Afforestation and deforestation assessment;
      • Forest fire surveillance;
      • Forest health and vigor monitoring;
      • Detailed survey and inventory of the existing bio-resources;
      • Environmental impact assessment including pollution (land, water and air);
      • Mapping and monitoring of tiger reserves, elephant corridors, biosphere reserves, mangroves and coral reefs;
      • Assessment of fuel wood and timber resources; and
      • Environmental hazard related studies like zonation and damage assessment (floods, drought, cyclone, landslide, volcano, earthquake etc.)
    • Applications in Geology and Mineral Resources
      • Mapping of surfacial deposits and bedrock;
      • Lithological and structural mapping;
      • Mineral prospecting and exploration; and
      • Geo – hazard mapping, monitoring and zonation.
    • Applications in Oceanography
      • Identification of potential fishery zones;
      • Phytoplankton abundance and habitat assessment;
      • Observation of marine pollution and sedimentation and its impact; and
      • Assessment of sediment dynamics, tidal fluctuations, sea level changes and coastal circulations.
    • Applications in Water Resources
      • Mapping of surface water bodies;
      • Identification of potential ground water resources;
      • Wetland mapping and monitoring;
      • Snow pack and glacial monitoring;
      • Ice thickness measurements;
      • Rivers, watersheds and ice lake monitoring and modelling;
      • Flood mapping and monitoring;
      • Monitoring reservoir extends over seasons and irrigation scheduling and flood management; and
      • Snowmelt runoff forecasting.
    • Applications in Urban Sector
      • Mapping and Land Use Land Cover classification;
      • Urban sprawl analysis;
      • Identification of illegal encroachment, and constructions;
      • Property tax assessment and estimations;
      • Transport and urban planning;
      • Mapping of utilities and services;
      • Population estimation;
      • Slum detection and monitoring; and
      • Site suitability analysis.
    • Applications in Cartography
      • Mapping is an essential component of the resource management process, and mapped information is a common byproduct of the analysis of remotely sensed data from IRS series satellites.
      • The Cartosat series is designed specifically for geoengineering mapping and DTM (Digital Terrain Modelling) or DEM (Digital Elevation Modelling).
      • Natural and man-made features such as transportation networks, settlements, and administrative boundaries are represented spatially in GIS (Geographical Information System) using geo-referenced data and integrated with attribute or non-spatial information.
      • For planning, evaluation, and monitoring, as well as civilian and military reconnaissance and land use planning, baseline, thematic, and 2D and 3D topographical maps are required.
  • Advantages of Remote Sensing Satellites
    • The advantages of satellite-based remote sensing over other techniques include its broad coverage, time savings, and tremendous cost effectiveness.
    • Large area coverage allows for a regional survey of a wide range of themes and the identification of large features.
    • Coverage that is repeated, allowing monitoring of dynamic themes such as water, agriculture, and so on.
    • Data collection at various heights.
    • Data collection in inaccessible areas.

Q. With reference to the use of Nano-technology in health sector, which of the following statement(s) is/are correct?

  1. Targeted drug delivery is made possible by nanotechnology.
  2. Nanotechnology can largely contribute to gene therapy.

Select the correct answer using the codes given below.

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (c) Both 1 and 2

  • Nanotechnology or nanotech in short is the technology that involves the manipulation of matter on atomic, molecular, and supramolecular scales, which is about 1 to 100 nanometers. One nanometer (nm) is one-billionth or (10-9) of a meter.
  • It is the manipulation and use of materials and devices so tiny that nothing can be built any smaller.
  • It involves a multidisciplinary approach involving fields such as applied physics, materials science, chemistry, biology, surface science, robotics, engineering, electrical engineering and biomedical engineering.
  • Areas of physics such as nanoelectronics, nanomechanics, nanophotonics, and nanoionics have evolved during the last few decades to provide a basic scientific foundation of nanotechnology.

Read here: Nanotechnology

Q. H1N1 virus is sometimes mentioned in the news with reference to which one of the following diseases?

(a) AIDS

(b) Bird flu

(c) Dengue

(d) Swine flu

Answer: (d) Swine flu

Influenza A virus subtype H1N1
  • In virology, influenza A virus subtype H1N1 (A/H1N1) is a subtype of influenza A virus.
  • Swine flu (H1N1) is an infection that a type of flu (influenza) virus. It’s called swine flu because it’s similar to a flu virus that affects pigs (swine).
    • The virus leads to a lung (respiratory) disease in pigs. Swine flu (H1N1) is a respiratory infection in humans.
  • Major outbreaks of H1N1 strains in humans include the 1918 Spanish flu pandemic, the 1977 Russian flu pandemic and the 2009 swine flu pandemic.
  • It is an orthomyxovirus that contains the glycoproteins hemagglutinin (H) and neuraminidase (N), antigens whose subtypes are used to classify the strains of the virus as H1N1, H1N2 etc.
    • Hemagglutinin causes red blood cells to clump together and binds the virus to the infected cell.
    • Neuraminidase is a type of glycoside hydrolase enzyme which helps to move the virus particles through the infected cell and assist in budding from the host cells.
  • Some strains of H1N1 are endemic in humans and cause a small fraction of all influenza-like illness and a small fraction of all seasonal influenza, for instance in 2004–2005.
    • Other strains of H1N1 are endemic in pigs (swine influenza) and in birds (avian influenza).
Types of Influenza Virus

Bird flu

  • Avian influenza, often referred to as bird flu, is a highly contagious viral infection that primarily affects birds, particularly wild birds and domestic poultry.
  • In 1996, highly pathogenic avian influenza H5N1 virus was first identified in domestic waterfowl in Southern China. The virus is named A/goose/Guangdong/1/1996.
  • Transmission to Humans and Related Symptoms:
    • Human cases of H5N1 avian influenza occur occasionally, but it is difficult to transmit the infection from person to person.
    • As per World Health Organisation(WHO), when people do become infected, the mortality rate is about 60%.
  • Avian Influenza and India:
    • Initial Outbreak:
      • The initial outbreak of Highly Pathogenic Avian Influenza (HPAI) H5N1 in India occurred in 2006 in Navapur, Maharashtra, and was followed by annual outbreaks.
      • H5N8 was first observed in India in November 2016, mainly affecting wild birds across five states, with Kerala reporting the most cases.
      • The disease has been reported in 24 states and union territories, resulting in the culling of over 9 million birds to control its spread.
    • Related Initiative:
      • India’s approach to controlling Highly Pathogenic Avian Influenza (HPAI) follows a “detect and cull” policy as outlined in the National Action Plan for Prevention, Control, and Containment of Avian Influenza (revised – 2021)
  • Treatment:
    • Antivirals have demonstrated effectiveness in the treatment of avian influenza virus infections in humans, lowering severity and the risk of death.
  • Acquired immunodeficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV).
  • HIV stands for Human Immunodeficiency Virus, which is a virus that attacks the immune system in the human body.
  • It primarily targets and damages CD4 immune cells, which are essential for the body’s ability to fight infections and diseases.
    • Over time, HIV weakens the immune system, leaving the body vulnerable to opportunistic infections and cancers.
  • Transmission:
    • HIV is primarily spread through the exchange of certain bodily fluids such as blood, semen, vaginal fluids, and breast milk.
  • Severity:
    • If left untreated, the virus destroys a person’s immune system and they are said to be in the Acquired Immunodeficiency Syndrome stage (AIDS) where they get several opportunistic infections that may result in death.
  • Cure:
    • Although there are no cures for the infection at present, the disease can be managed using antiretroviral therapy.
      • These medicines suppress the replication of the virus within the body, allowing the number of CD4 immune cells to bounce back.
  • Dengue is a self-limiting febrile illness with symptoms ranging from asymptomatic to severe.
  • Dengue is a mosquito-borne tropical disease caused by the dengue virus (Genus Flavivirus), transmitted by several species of female mosquito within the genus Aedes, principally Aedes aegypti.
    • This mosquito also transmits chikungunya and Zika infection.
  • Serotypes of Dengue:
    • There are 4 distinct, but closely related, serotypes (separate groups within a species of microorganisms that all share a similar characteristic) of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4).
  • Symptoms:
    • Sudden high fever, severe headaches, pain behind the eyes, severe bone, joint, and muscle pain, etc.
  • Dengue Vaccine:
    • The dengue vaccine CYD-TDV or Dengvaxia was approved by the US Food & Drug Administration in 2019, the first dengue vaccine to get the regulatory nod in the US.
      • Dengvaxia is basically a live, attenuated dengue virus which has to be administered in people of ages 9 to 16 who have laboratory-confirmed previous dengue infection and who live in endemic areas.
    • Researchers at India’s National Centre for Biological Sciences, in collaboration with nine other institutions in India, Africa, and the US, have developed India’s first and only DNA vaccine candidate for dengue fever.
      • In preliminary trials on mice, the candidate generated a robust immune response and improved survival rates after exposure to the disease.
  • Controlling Dengue Using Bacteria:
    • Researchers from the World Mosquito Program have used mosquitoes infected with Wolbachia bacteria to successfully control dengue, leading to a 77% reduction in incidence in Indonesia.

Q. With reference to ‘Near Field Communication (NFC) Technology’, which of the following is/are correct?

  1. It is a contactless communication technology that uses electromagnetic radio fields.
  2. NFC is designed for use by devices which can be at a distance of even a metre from each other.
  3. NFC can use encryption when sending sensitive information.

Select the correct answer using the codes given below.

(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (c) 1 and 3 only

Near Field Communication Technology
  • NFC is a short-range wireless connectivity technology that allows NFC-enabled devices to communicate with each other and transfer information quickly and easily with a single touch – whether to pay bills, exchange business cards, download coupons, or share a document.
  • NFC transmits data through electromagnetic radio fields, to enable communication between two devices. Both devices must contain NFC chips, as transactions take place within a very short distance.
    • NFC-enabled devices must be either physically touching or within a few centimetres from each other for data transfer to occur.
  • In 2004, consumer electronics companies, Nokia, Philips and Sony together formed the NFC Forum, which outlined the architecture for NFC technology to create powerful new consumer-driven products.
  • Nokia released the first NFC-enabled phone in 2007.
  • Other Applications:
    • It is used in contactless banking cards to perform money transactions or to generate contact-less tickets for public transport.
      • Contactless cards and readers use NFC in several applications from securing networks and buildings to monitoring inventory and sales, preventing auto theft, and running unmanned toll booths.
    • It is present in speakers, household appliances, and other electronic devices that are controlled through smartphones.
    • It also has an application in healthcare, to monitor patient stats through NFC-enabled wristbands. NFC is used in wireless charging too.