Flash Card

LAKSHYA-75 [Day-12] Static Flash Cards for IAS Prelims 2020

Virtual Currencies; XPoSat; Kyasanur Forest Disease; Hybridisation; Foot and Mouth Disease; Fungi; International Protection (IP) Marking; IRNSS; Quantum size effect; Le Grand K
By IASToppers
March 18, 2020



Which object was used to define the magnitude of mass of the kilogram from 1989 until 20 May 2019?

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Solution: Le Grand K or International Prototype of the Kilogram (IPK)

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Le Grand K

  • In a subterranean vault in a suburb of Paris, a small rarely seen metal cylinder known as Le Grand K is present.
  • For 130 years, this golf-ball-sized hunk of 90% platinum and 10% iridium has served as the international prototype kilogram.
  • That means it was the single physical object by which all other kilograms across the planet were measured.
  • It is machined into a right-circular cylinder of about 39 millimeters height and same diameter to minimize its surface area.
  • The IPK and its six sister copies are stored at the International Bureau of Weights and Measures (BIPM) in an environmentally monitored safe in the lower vault located in the basement of the BIPM’s Pavilion de Breteuil in Saint Cloud on the outskirts of Paris. 
  • The IPK is rarely used or handled.
  • Copies of the IPK kept by national metrology laboratories around the world were compared with the IPK in 1889, 1948, and 1989 to provide traceability of measurements of mass anywherein the world back to the IPK.
  • Since its creation in 1889 (it was forged in London before being taken to France), the cylinder has only been removed from its secure housing once every 40 years. This rare appearance only occurs so that its mass can be checked against sister copies, which are housed in locations across the globe.
  • It is estimated that over the course of its lifetime, Le Grand K has lost 50 micrograms of mass.
  • In 2019, the kilogram is redefined in terms of the Planck constant. This is a fixed quantity tied in with E=MC2 and quantum theory, specifying the amount of energy carried by a single particle of light, or photon. And that’s just the most extremely simplified version


  • Every year, May 20 is celebrated as World Metrology Day to commemorate the signing of the Meter Convention in 1875.
  • The International Bureau of Weights and Measures (BIPM) at Paris was founded as an outcome of this treaty.
  • It is the apex body responsible for scientific metrology.
  • Among other responsibilities, it is the custodian of Le Grand K or the International Prototype Kilogram (IPK)a globally valid standard of measuring mass or weight.
  • Standards are objects or ideas that are designated as being authoritative for some accepted reason.



Bitcoin is a digital currency. True or false?

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Correct Statement:

  • It is a virtual currency.

Enrich Your Learning:

What are Virtual Currencies?

  • Virtual currency is a type of unregulated digital currency that is only available in electronic form.
  • It can be defined as an electronic representation of monetary value that may be issued, managed, and controlled by private issuers, developers, or the founding organization.
  • Unlike regular money, virtual currency relies on a system of trust and may not be issued by a central bank or other banking regulatory authority.
  • It is stored and transacted only through designated software, mobile or computer applications, or through dedicated digital wallets.
  • The transactions of virtual currency occur over the internet through secure, dedicated networks.
  • Virtual currency is considered to be a subset of the digital currency group, which also includes cryptocurrencies, which exist within the blockchain network.
  • It is held within the blockchain network that is not controlled by a centralized banking authority.
  • Virtual currency is unregulated and therefore experiences dramatic price movements since the only real force behind trading is consumer sentiment.
  • A virtual currency can have restricted usage, and it may be in circulation only among the members of a specific online community.

The term ‘Virtual currency’

  • The term came into existence around 2012, when the European Central Bank (ECB) defined virtual currency to classify types of“digital money in an unregulated environment, issued and controlled by its developers and used as a payment method among members of a specific virtual community”.

Is virtual currency and digital currency same?

  • Virtual currency is different than digital currency since digital currency is simply currency issued by a bank in digital form.
  • Digital currency is the overall superset that includes virtual currency, which in turn includes cryptocurrencies. Compared to virtual currency, a digital currency covers a larger group that represents monetary assets in digital form.
  • Digital currency can be regulated or unregulated whereas a virtual currency often remains unregulated.

Examples of virtual currencies circulating across the world

  • Cryptocurrencies like Bitcoin and Ethereum are considered to be a part of the virtual currency group. 
  • The other popular cryptocurrencies are: Litecoin, Peercoin, Cardano
  • A cryptocurrency uses cryptography technology that keeps the transactions secure and authentic, and alsohelps to manage and control the creation of new currency units. 



What does the effect derived from reducing the size of materials to the nanometre range called?

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Solution: Quantum Size Effect

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Quantum size effect

  • The quantum size effect describes the accepted theory of quantum mechanics with respect to particle confinement. 
  • Quantum size effect describes the ‘physics of electron properties’ in solids with great reductions in particle size.
  • One of the most direct effects of reducing the size of materials to the nanometer range is the appearance of quantization effects due to the confinement of the movement of electrons.
  • This leads to discrete energy levels depending on the size of the structure as it is known from the simple potential well treated in introductory quantum mechanics.
  • Materials reduced to the nanoscale can suddenly show very different properties compared to what they show on a macroscale. For instance, opaque substances become transparent (copper); inert materials become catalysts (platinum); stable materials turn combustible (aluminium); solids turn into liquids at room temperature (gold); insulators become conductors (silicon).
  • Nanomaterials are typically between 0.1 and 100 nanometers (nm) in size – with 1 nm being equivalent to one billionth of a meter (10-9 m).
  • This is the scale at which the basic functions of the biological world operate – and materials of this size display unusual physical and chemical properties.
  • These profoundly different properties are due to an increase in surface area compared to volume as particles get smaller – and also the grip of weird quantum effects at the atomic scale.
  • Materials can be produced that are nanoscale in one dimension (for example, very thin surface coatings), in two dimensions (for example, nanowires and nanotubes) or in all three dimensions (for example, nanoparticles and quantum dots).
  • The bulk properties of any material are merely the average of all the quantum forces affecting all the atoms that make up the material.
  • As you make things smaller and smaller, you eventually reach a point where the averaging no longer works and you have to deal with the specific behavior of individual atoms or molecules – behavior that can be very different to when these atoms are aggregated into a bulk material.

What is the result when materials are reduced to nanoscale?

  • Materials reduced to the nanoscale can suddenly show very different properties compared to what they show on a macroscale.
  • For example, opaque substances become transparent (copper); inert materials become catalysts (platinum); stable materials turn combustible (aluminium); solids turn into liquids at room temperature (gold); insulators become conductors (silicon).



The seven satellites of Indian Regional Navigation Satellite System (IRNSS) have been put into which satellite orbits?

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Solution: Geostationary Orbit (3 satellites) and Geosynchronous orbit (4 satellites)

Enrich Your Learning:


  • The Indian Regional Navigation Satellite System (IRNSS),with an operational name of NavIC, is an autonomous regional satellite navigation system, that provides accurate real-time positioning services.
  • The system at-present consist of 7 satellites (3 in Geostationary Orbits and 4 in Geosynchronous orbit).
  • It can provide accurate position information service to users in India and the region, extending up to 1,500 km from its boundary which is its Primary Service Area. It will provide a position accuracy of better than 20 m in the primary service area.
  • An extended service area lies between the primary service area and a rectangle area enclosed by the 30th parallel south to the 50thparallel north and the 30th meridian east to the 130th meridian east.
  • IRNSS is independent of India’s existing regional satnav system, GAGAN (GPS Aided GEO Augmented Navigation), built by ISRO in conjunction with the Airports Authority of India. GAGAN is primarily used by the commercial airline industry and by scientists studying the ionosphere.
  • Since the average lifespan of the IRNSS satellites is 9.5 years for geostationary and 11 for geosynchronous, ISRO plans to build four more satellites as backup to be augmented to the existing constellation.

It will provide two types of services, namely,

  1. Standard Positioning Service (SPS) which is provided to all the users
  2. Restricted Service (RS), which is an encrypted service provided only to the authorized users.

Important applications of NavIC (the IRNSS constellation) include:

  • Terrestrial, aerial and marine navigation;
  • Disaster management;
  • Vehicle tracking and fleet management
  • Precise timing (as for ATMs and power grids);
  • Mapping and geodetic data capture
  • Fisheries (fishermen can receive alerts related to bad weather and high waves)
  • Resource Management (helps Government agencies to manage resources efficiently using Geo-tagging and Geo-fencing techniques. Alert messages are generated when there is a movement of object beyond permissible limits)
  • Mapping and geodetic data capture (for terrestrial navigation aid for hikers and travellers)

Is India the only country to have its positioning system?

  • Several other countries have its own positions system. For example, the Global Positioning System (GPS) is a satellite-based radio navigation system that is owned by the United States.
  • Apart from GPS, there is GLONASS of Russia, Galileo of the European Union and BeiDou Navigation Satellite System (BDS) of China.



Who publishes International Protection (IP) Marking or IP Code?

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Solution: International Electro Technical Commission (IEC)

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IP Code OR International Protection (IP) Marking

  • IP Code stands for the International Protection marking, or Ingress Protection Code.
  • It is a standard published by the International Electro technical Commission (IEC).
  • It classifies and rates the degree of protection provided by mechanical casings and electrical enclosures against intrusion, dust, accidental contact, andwater.
  • The standard aims to provide users more detailed information than vague marketing terms such as waterproof. For example, a cellular phone rated at IP68 is “dust resistant” and can be “immersed in 1.5 meters of freshwater for up to 30 minutes”.
    • The first digit shows the extent to which enclosures are protected against particles, and protection to others from enclosed hazards.
    • The second digit indicates the extent of protection against water.

Various IP Ratings are as follows:

IP44 Rating / IP44 Certification:

  • The First digit (4) shows Protection against contact with live or moving parts inside the enclosure by tools, wires, or such objects of thickness greater than 1mm.
  • Protection against ingress of small solid foreign bodies (diameter greater than 1mm) excluding the ventilation openings (intake and discharge of external fans) and the drain hole of enclosed machine, which may have degree 2 protection.
  • The second digit indicates that water splashed against the enclosure from any direction shall have no harmful effect.

IP54 Rating / IP54 Certification:

  • First digit (5) shows complete protection against contact with live or moving parts inside the enclosure.
  • Protection against harmful deposits of dust.
  • The ingress of dust is not totally prevented, but cannot enter in an amount sufficient to interfere with satisfactory operation of the machine.
  • Second digit (4) shows that Water projected by a nozzle against the enclosure from any direction shall have no harmful effect.

IP55 Rating / IP55 Certification:

  • First digit (5) is already described above. The second digit (5) shows that water projected by a nozzle against the enclosure from any direction shall have no harmful effect.

IP56 Rating / IP56 Certification:

  • The first digit (5) is already described above. The second digit (6) shows that water from heavy seas or water projected from jets shall not enter the machine in any harmful quantity.

IP65 Rating / IP65 Certification:

  • The first digit (6) shows complete protection against contact with live or moving parts inside the enclosure and against the ingress of dust. Meaning of second digit (5) already described above.

IP66 Rating / IP66 Certification:

  • The first digit (6) & the second digit (6) both are described above.



Mushroom is an example of fungi. True OR False.

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Solution: True

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  • A fungus is a eukaryotic organism that is a member of the kingdom Fungi.
  • Fungi can be single celled or very complexmulticellular organisms. They are also called the Eumycota (“true fungi” or eumycetes).
  • They are found in just about any habitat but most live on the land, mainly in soil or on plant material rather than in sea or fresh water.
  • Most fungi are largely invisible to the naked eye, living for the most part in soil, dead matter, and as symbionts of plants, animals, or other fungi.
  • Yeasts, molds, and mushrooms are examples of fungi.
  • The fungi are heterotrophic organisms possessing a chitinous cell wall.
  • They perform an essential role in all ecosystems in decomposing organic matter and are indispensable in nutrient cycling and exchange.
  • Sexual and asexual reproduction of the fungi is commonly via spores, often produced on specialized structures or in fruiting bodies.
  • Some species have lost the ability to form reproductive structures, and propagate solely by vegetative growth.
  • The fungi are more closely related to animals than plants, yet the discipline of biology devoted to the study of fungi, known as mycology, often falls under a branch of botany.

Types of fungi

Fungi are subdivided on the basis of their life cycles, the presence or structure of their fruiting body and the arrangement of and type of spores (reproductive or distributional cells) they produce.

The three major groups of fungi are:

  1. Molds – Moulds are made up of very fine threads (hyphae). Hyphae grow at the tip and divide repeatedly along their length creating long and branching chains. The hyphae keep growing and intertwining until they form a network of threads called a mycelium.
  2. Macroscopic filamentous fungi that form large fruiting bodies. Sometimes the group is referred to as ‘mushrooms’, but the mushroom is just the part of the fungus we see above ground which is also known as the fruiting body.
  3. Yeasts – Yeasts are small, lemon-shaped single cells that are about the same size as red blood cells. They multiply by budding a daughter cell off from the original parent cell.



The Foot and Mouth Disease is a bacterial disease. True or False?

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Correct Statement:

  • It is a viral disease caused by

Enrich Your Learning:

Foot and Mouth Disease

  • Foot-and-mouth disease is an infectious and sometimes fatalviral disease that affects cloven-hoofed animals, including domestic and wild bovid.
  • It is caused by
  • The virus causes a high fever for between two and six days, followed by blisters inside the mouth and on the feet that may rupture and cause lameness.
  • It can be spread by infected animals comparatively easily through contact with contaminated farming equipment, vehicles, clothing, feed and by domestic and wild predators.
  • Susceptible animals include cattle, water buffalo, sheep, goats, pigs, antelope, deer, and bison.
  • Humans are very rarely infected. The disease is mainly seen in children below five years of age.
  • The FMD virus can be transmitted in a number of ways, including close-contact animal-to-animal spread, long-distance aerosol spread and fomites, or inanimate objects, typically fodder and motor vehicles.
  • The clothes and skin of animal handlers such as farmers, standing water, and uncooked food scraps and feed supplements containing infected animal products can harbor the virus, as well.

How the virus causes the disease?

  • Infection occurs when the virus particle is taken into a cell of the host.
  • The cell is then forced to manufacture thousands of copies of the virus, and eventually bursts, releasing the new particles in the blood.
  • The virus is genetically highly variable, which limits the effectiveness of vaccination.



The process which explains the structure of simple molecules using atomic orbitals is called?

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Solution: Orbital Hybridisation or Hybridisation

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  • Chemist Linus Pauling introduced the concept of hybridization in 1931 to explain the characteristic geometrical shapes of polyatomic molecules like Methane (CH4) using atomic orbitals.
  • According to him the atomic orbitals combine to form new set of equivalent orbitals known as hybrid orbitals. Unlike pure orbitals, the hybrid orbitals are used in bond formation.
  • The phenomenon is known as hybridisation which can be defined as the process of intermixing of the orbitals of slightly different energies so as to redistribute their energies, resulting in the formation of new set of orbitals of equivalent energies and shape.
  • For example, when one 2s and three 2p-orbitals of carbon hybridise, there is the formation of four new sp3 hybrid orbitals.
  • There are mainly three types of hybridization namely: sp, sp2 and sp3.
  • Hybrid orbitals are very useful in the explanation of molecular geometryand atomic bonding properties and are symmetrically disposed in space. 

Salient features of Hybridisation:

The main features of hybridisation are as under:

  • The number of hybrid orbitals is equal to the number of the atomic orbitals that get hybridised.
  • The hybridised orbitals are always equivalent in energy and shape.

Conditions for hybridisation:

  • The orbitals present in the valence shell of the atom are hybridised.
  • The orbitals undergoing hybridisation should have almost equal energy.
  • Promotion of electron is not essential condition prior to hybridisation.
  • It is not necessary that only half filled orbitals participate in hybridisation. In some cases, even filled orbitals of valence shell take part in hybridisation



 Kyasanur Forest Disease can transmit from Human to Human via airborne transmission. True OR False.

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Correct Statement

  • No person-to-person transmission has been described.

Enrich Your Learning:

Kyasanur Forest Disease

  • Kyasanur Forest disease (KFD) is caused by Kyasanur Forest disease virus (KFDV), a member of the virus family 
  • KFDV was identified in 1957 when it was isolated from a sick monkey from the Kyasanur Forest in Karnataka (formerly Mysore) State, India. Since then, between 400-500 humans cases per year have been reported.
  • Hard ticks (Hemaphysalis spinigera) are the reservoir of KFD virus and once infected, remain so for life.
  • Rodents, shrews, and monkeys are common hosts for KFDV after being bitten by an infected tick.
  • KFDV can cause epizootics with high fatality in primates.


  • Transmission to humans may occur after a tick bite or contact with an infected animal, most importantly a sick or recently dead monkey.
  • No person-to-person transmission has been described.
  • Furthermore, there is no evidence of disease transmission via the unpasteurized milk of any of these animals.
  • There is no specific treatment for KFD, but early hospitalization and supportive therapy is important.
  • A vaccine does exist for KFD and is used in endemic areas of India.

Signs and Symptoms

  • After an incubation period of 3-8 days, the symptoms of KFD begin suddenly with chills, fever, and headache.
  • Severe muscle pain with vomiting, gastrointestinal symptoms and bleeding problems may occur 3-4 days after initial symptom onset.
  • Patients may experience abnormally low blood pressure, and low platelet, red blood cell, and white blood cell counts.
  • The estimated case-fatality rate is from 3 to 5% for KFD.

Risk of Exposure

  • KFD has historically been limited to the western and central districts of Karnataka State,
  • However, in November 2012, samples from humans and monkeys tested positive for KFDV in the southernmost district of the State which neighbors Tamil Nadu State and Kerala State, indicating the possibility of wider distribution of KFDV. 



What is the objective of XPoSat that will be launched by Indian Space Research Organisation (ISRO) in 2021?

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Solution: Studying polarisation of cosmic X-rays

Enrich Your Learning:


  • The X-ray Polarimeter Satellite(XPoSat) is a planned space observatory to study polarisation of cosmic X-rays.
  • It is planned to be launched in 2021, and to provide a service time of at least five years.
  • The telescope is being developed by the Indian Space Research Organisation (ISRO) and the Raman Research Institute.
  • It will be carrying a payload named ‘polarimeter instrument in X-rays’ (POLIX) made by Raman Research Institute.
  • POLIX will study degree and angle of polarisation of bright X-ray sources in energy range 5-30 keV.
  • The spacecraft will be placed in a circular 500-700km orbit.
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