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Science & technology

5 Solved Questions with Answers
  • 2017

    6. Stem cell therapy is gaining popularity in India to treat a wide variety of medical conditions including leukaemia, Thalassemia, damaged cornea and several burns. Describe briefly what stem cell therapy is and what advantages it has over other treatments? (2017)

    Stem cells refer to class of undifferentiated cells that have ability to differentiate into various specialized cells. These cells have potential to develop into many cell types in body during early life and growth. In many tissues these cells work as a kind of internal repair system to replenish other cells.

    This ability to repair and regenerate damaged cell is used in stem cell therapy for treatment of various diseases. In this therapy, stems cells are administered systematically and directly in high concentration in damaged tissues for self-healing. Stems cells for this purpose are obtained from the patient’s bone marrow, fat and umbilical cord tissue or blood. This therapy is being promoted as the next panacea for all ills.

    • Diseases that were earlier considered degenerative, incurable and irreversible are being treated with the help of stem cell therapy. The list includes diseases like diabetes, heart disease, spinal cord injuries, Parkinson's, Alzheimer's disease etc.
    • Blood stem cells are increasingly being used to treat diseases of the blood. Some methods of treatment like chemo therapy used in treatment of cancer destroys bone marrow also. Stem cell transplant can be used to replace such bone marrow.     

    India is among the frontrunner in stem cell therapy. Clinical trials are being performed to treat genetic, metabolic and blood related conditions. Stem cell has the potential to replace expensive, painstakingly protracted and routinely ineffective conventional therapy for treating a multitude of acute and chronic ailments.

  • 2017

    7. India has achieved remarkable successes in unmanned space missions including the Chandrayaan and Mars Orbiter Mission, but has not ventured into manned space mission. What are the main obstacles to launching a manned space mission, both in terms of technology and logistics? Examine critically. (2017)

    India has been able to carry out unmanned spaced mission but lacks the full fledged capabilities in manned space missions. Although some developments have taken place in terms of technology and logistics, India is still facing some hurdles in launching manned space missions.


    • India lacks the technology to carry heavy payloads into space.
    • Full capabilities in re-entry technologies are yet to be developed.
    • India could not get international cooperation in the field such as cryogenic technology at early stage.
    • ISRO is planning to launch manned space programme by 2021-24. Towards this end, it has unveiled a prototype of its first crew capsule (4 metre high module) designed to carry two people into low earth orbit.
    • India in 2017 launched the GSLV (Geosynchronous Satellite Launch Vehicle) Mark 3 from Satish Dhawan Space Centre. It carried a three ton payload, including “Crew Module Atmospheric Re-entry Experiment (CARE)”. However the third stage of cryogenic technology in GSLV is still not fully developed. GSLV Mark 3 will also be upgraded and tested to carry payloads upto 8 tonnes.
    • India is also working on Space Capsule Recovery Experiment-2 (SRE-2) that will demonstrate critical technologies required for recoverable launch vehicles.


    • India is depended mainly on single type of launch vehicle such as that of PSLV which hampers the capacity expansion of the programme.
    • India does not have its own global navigation system.
    • Funding and finance is essential to develop various equipments, technology  and new tools required in the coordination of a manned space programme. But ISRO is still waiting for the government approval and funding for a human space flight programme.

    Some scientists hold the view that private players have much more flexibility, freedom and risk taking abilities than the state owned agencies. Thus there should be more participation of private players in space programmes. India must realize that China launched its manned space mission to space in 2016 and will establish its permanent space station by 2022. Therefore India should also increase its footprints in manned space mission capabilities at the earliest.

  • 2016

    12. Discuss India’s achievements in the field of Space Science and Technology. How the application of this technology has helped India in its socio-economic development? (2016)

    India embarked on developing space science and technology in an era when it was being criticized for spending money on such expensive technologies when it’s priority should be fighting rampant poverty that prevails.

    However, our visionary leaders like Nehru and scientists prevailed over such criticisms and led India onto a path of great technological achievements. It has shown its proverbs in the field through achievements like Mars Orbiter Mission at a cost ten times lower than US’s similar project, Chandrayan mission which made ISRO sixth space organization to send orbiter to moon, developing it’s own navigation system through NAVIC (IRNSS). Thus ending its dependence on GPS. It has also made major strides in launch vehicles by developing Reusable Launch Vehicle (RLV), GSLV with indigenous cryogenic stage which made India self reliant in launching 2 ton class communication satellites, record launch of 20 satellites in 2016 etc.

    Apart from being a mighty achievement, these achievements have also helped in socio-economic developments of the country. Through metrological data sent by satellites, it has been possible to gauge weather changes, arrival of monsoon and extent of rainfall, monitoring cyclones in advance which has helped farmers and citizens through advanced preparedness in general and in events of disasters. The communication satellites have enabled data connectivity to rural India eventually helped in digital India. NAVIC has made India self reliant thus saving resources, ensuring reliable data for army, farmers, tourists, navigators, fishermen.

  • 2016

    13. Why is nanotechnology one of the key technologies of the 21st century? Describe the salient features of Indian Government’s Mission on Nanoscience and Technology and the scope of its application in the development process of the country (2016)

    In the recent years nanotechnology has revolu-tionized scientific research across the globe in a big way. Today, from agriculture to aerospace research, nanotechnology's impact is being felt. Research in nanotechnology spans across an array of fields such as health, environment, agriculture, food and beverages, product development, space technology, power generation, genetics, biotechnology, forensic science, electronics and communications.

    At a commercial level the impact of nanotechnology is on three major industries, namely consumer products, electronics and healthcare. Some applications that make nanotechnology one of the key technologies in 21st century are discussed below:

    • Nanosilver provides an effective, broad-spectrum antimicrobial coating to the surface of various consumer products. Therefore silver nanotechnology is being used in a wide range of consumer products such as wound dressings, textiles, food storage containers, paints and personal care appliances.
    • Nanotechnology has significantly scaled down the size of transistors and chips used in the production of computers and other electronic goods.
    • Nanotechnology has made great strides in the field of medicine. Several nano- sized gadgets and materials are being developed to diagnose and treat diseases like cancer more effectively. Nano-pharmacology helps to produce smart drugs that have negligible side effects.
    • Nanoscale thin films on eyeglasses, computer and camera displays, windows, and other surfaces can make them water-repellent, antireflective, self-cleaning, resistant to ultraviolet or infrared light, antifog, antimicrobial, scratch-resistant, or electrically conductive.
    • Scientists are coating fabrics with a thin layer of zinc oxide nanoparticles that give better protection from UV radiation.
    • Using nanoparticles in the manufacture of solar cells is beneficial as they can reduce manufacturing costs by using a low temperature process.

  • 2017

    16. Give an account of the growth and development of nuclear science and technology in India. What is the advantage of fast breeder reactor programme in India? (2017)

    India’s journey in the field of nuclear science and technology began with the formation of Department of Atomic Energy (DAE) in 1954. The aim was to harness nuclear resources for peaceful purposes. India had to surpass the obstacle of technology denial by capable nations.

    In this background  three-stage nuclear power programme was formulated by Dr. Homi Bhabha in 1950s to secure country’s long term energy independence, through use of uranium and thorium reserves found in the monazite sands of coastal regions of South India.

    The ultimate focus of the programme is on enabling thorium reserves of India to be utilised in meeting country's energy requirements. Thorium is particularly attractive for India, as it has not only around 1–2% of the global Uranium reserves, but one of the largest shares of global Thorium reserves at about 25% of the world's known Thorium reserves.

    The three stages adopted were

    • Natural uranium fuelled Pressurized Heavy Water Reactors (PWHR)
    • Fast Breeder Reactors (FBRs) utilizing plutonium based fuel
    • Advanced nuclear power systems for utilization of Thorium

    At present only stage 1 is operational and all 22 functional nuclear reactor in India belongs to this stage with total capacity of 6780 MW. At present, the fast breeder reactor programme in India is carried out by Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu.

    The advantage with a breeder reactor is that it generates more fissile material than it consumes. Also in the second stage, fast breeder reactors (FBRs) would use Plutonium-239, recovered by reprocessing spent fuel from the first stage, and natural uranium.

    This technology does not contribute to air pollution, except during mining and processing of Uranium ore. Breeder reactors use a small core, which is important to sustain chain reactions. Besides, they do not even need moderators for slowing down neutrons, as they use fast neutrons.

    In FBRs, plutonium-239 undergoes fission to produce energy, while the uranium-238 present in the fuel transmutes to additional plutonium-239. Furthermore, once a sufficient amount of plutonium-239 is built up, thorium will be used in the reactor, to produce Uranium-233. This uranium is crucial for the third stage. 

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