Practice Test: Science and Technology- 2 - UPSC MCQ

• Nuclear fission is a reaction in which the nucleus of an atom splits into two or smaller nuclei. The fission process often produces gamma photons and releases a very large amount of energy even by the energetic standards of radioactive decay.
• Nuclear fission produces more radioactive waste than nuclear fusion because very few radioactive particles are produced in the case of nuclear fusion. Nuclear fission power plants have the disadvantage of generating unstable nuclei; some of these are radioactive for millions of years. Fusion on the other hand does not create any long-lived radioactive nuclear waste. A fusion reactor produces helium, which is an inert gas. It also produces and consumes tritium within the plant in a closed circuit. Tritium is radioactive (a beta emitter) but its half-life is short. It is only used in low amounts. Hence statement 1 is correct.
• Nuclear Fission reaction does not occur normally in nature.
• The isotopes uranium-235 and plutonium-239 were selected by atomic scientists because they readily undergo fission. Fission occurs when a neutron strikes the nucleus of either isotope, splitting the nucleus into fragments and releasing a tremendous amount of energy. The fission process becomes self-sustaining as neutrons produced by the splitting of atom strike nearby nuclei and produce more fission. This is known as a chain reaction and is what causes an atomic explosion. Hence statement 2 is correct.
• To make a hydrogen bomb, one would still need uranium or plutonium as well as two other isotopes of hydrogen, called deuterium and tritium. The hydrogen bomb relies on fusion, the process of taking two separate atoms and putting them together to form a third atom. Hydrogen bombs are also harder to produce but lighter in weight, meaning they could travel farther on top of a missile. Although hydrogen bombs do use fusion reactions, they require an additional fission bomb to detonate.
• The energy released by fission is a million times greater than that released in chemical reactions; but lower than the energy released by nuclear fusion. Hence statement 3 is correct.
• Nuclear Fusion occurs when two atoms slam together to form a heavier atom, like when two hydrogen atoms fuse to form one helium atom. Fusion occurs in stars, such as the sun.
  • The energy released by fusion is three to four times greater than the energy released by fission.

• Standalone 5G and Non-Standalone 5G
  • 5G networks are deployed mainly in two modes: standalone and non-standalone.
  • Both architectures have advantages and disadvantages, and the path chosen by operators primarily reflects their view of the market for the new technology.
  • In the standalone mode the 5G network operates with dedicated equipment, and runs parallel to the existing 4G network, while in a non-standalone way, the 5G network is supported by the 4G core infrastructure.
  • Given that the non-standalone networks are built on existing infrastructure, the initial cost and the time taken to roll out services through this track are significantly less than standalone networks.
• Non-Standalone 5G
  • The initial rollouts of 5G networks provide customers with higher data transfer speeds by pairing a 5G Radio Access Network (RAN) with the LTE Evolved Packet Core (EPC). Because the 5G RAN remains reliant on the 4G core network to manage control and signaling information and the 4G RAN continues to operate, this is called a Non-Standalone Architecture.
  • By leveraging the existing infrastructure of a 4G network, carriers are able to provide faster and more reliable Enhanced Mobile Broadband (eMBB) without completely reworking their core network technology and pushing customers to new devices. Non-Standalone 5G provides a transitionary platform for carriers and customers alike.
• Standalone 5G
  • Standalone 5G does not depend on an LTE EPC to operate. Instead, it pairs 5G radios with a cloudnative 5G core network. The 5G core itself is designed as a Service Based Architecture (SBA) that virtualizes network functions altogether, providing the full range of 5G features enterprise needs for factory automation, autonomous vehicle operation, and more.
• Comparing Standalone 5G and Non-Standalone 5G
  • NSA 5G helps network operators maximize their existing LTE infrastructure while providing enterprises and users with faster and more reliable communications than ever before, thanks to 5G’s eMBB. But eMBB only scratches the surface of 5G’s promise. Non-standalone networks are built on existing infrastructure. Hence, statement 2 is correct.
  • The SA 5G core architecture enables a host of new features and functionality beyond more bandwidth. These include Ultra-Reliable Low Latency Communications (URLCC), a key feature for applications requiring near-real-time responsiveness–things like autonomous driving vehicles, precision robotics, and machine vision. Massive IoT, with specialized machine-to-machine communication protocols, is also a key feature associated with Standalone 5G. In the standalone mode, the 5G network operates with dedicated equipment and runs parallel to the existing 4G network. Hence, statement 1 is correct.

• When fats and oils are oxidised, they become rancid and their smell and taste change. Usually substances which prevent oxidation (antioxidants) are added to foods containing fats and oil. Keeping food in air tight containers helps to slow down oxidation. The chips manufacturers usually flush bags of chips with gas such as nitrogen to prevent the chips from getting oxidised.

Hence option (b) is the correct answer.

• Mitochondria are known as the powerhouse of the cell.
  • The energy required for various chemical activities needed for life is released by mitochondria in the form of ATP (Adenosine Triphosphate) molecules. [If Mitochondria is the Power Plant. ATP is the Electricity].
  • ATP is known as the energy currency of the cell. The body uses energy stored in ATP for making new chemical compounds and for mechanical work.
• Lysosomes are a kind of waste disposal system of the cell.
  • Lysosomes help to keep the cell clean by digesting any foreign material as well as worn-out cell organelles.
  • Foreign materials entering the cell, such as bacteria or food, as well as old organelles end up in the lysosomes, which break them up into small pieces.
  • Lysosomes are able to do this because they contain powerful digestive enzymes capable of breaking down all organic material. During the disturbance in cellular metabolism, for example, when the cell gets damaged, lysosomes may burst and the enzymes digest their own cell.
  • Therefore, lysosomes are also known as the ‘suicide bags’ of a cell.
• The golgi apparatus consists of a system of membrane-bound vesicles arranged approximately parallel to each other in stacks called cisterns.
  • These membranes often have connections with the membranes of ER and therefore constitute another portion of a complex cellular membrane system.
  • The material synthesized near the ER is packaged and dispatched to various targets inside and outside the cell through the golgi apparatus. Its functions include the storage, modification and packaging of products in vesicles
• A ribosome is a complex molecular machine found inside the living cells that produce proteins from amino acids during a process called protein synthesis or translation.
  • The process of protein synthesis is a primary function, which is performed by all living cells.
  • Ribosomes are specialized cell organelles and are found in both prokaryotic and eukaryotic cells.
  • Every living cell requires ribosomes for the production of proteins.

Hence, option (b) is the correct answer.

Electric Bulb:

• The electric bulb is also known as an incandescent lamp, incandescent light globe, or incandescent light bulb.
• An electric bulb is a small and simple light source that uses a wire filament to glow on the application of electricity.
• The filament, which is a coiled thin wire, is made of tungsten. Tungsten is chosen as filament since it has a high melting point, which avoids the melting of the filament at high temperatures. Hence statement 1 is correct.
• The filament is enclosed in a globe-shaped glass mount and is connected with copper and lead wires connected to the lamp’s base.
• The wires and the filament are enclosed in like nitrogen, argon, or krypton - so that the filament doesn't catch fire. Since argon is an inactive gas, it protects the filament from burning as well as increases the lifetime of the filament. Thin glass is used to manufacture the bulb, preventing the air from reaching the filament to protect it from burning. Hence statement 2 is correct.
• When electric power is passed through the bulb, it reaches the filament through copper and lead wires. The base holds the bulb upright and connects to the electric circuit.
• Copper and lead wires let the electricity pass from the base to the tungsten filament. It causes the filament to emit light and glow.

• Concave mirror: A spherical mirror, whose reflecting surface is curved inwards, that is, faces towards the center of the sphere, is called a concave mirror. Concave mirrors are commonly used in torches, searchlights, and vehicle headlights to get powerful parallel beams of light. They are often used as shaving mirrors to see a larger image of the face. Dentists use concave mirrors to see large images of the teeth of patients. Large concave mirrors are used to concentrate sunlight to produce heat in solar furnaces. Hence pair 3 is correctly matched.
• Convex mirror: A spherical mirror whose reflecting surface is curved outwards, is called a convex mirror. Convex mirrors are commonly used as rear-view (wing) mirrors in vehicles. These mirrors are fitted on the sides of the vehicle, enabling the driver to see traffic behind him/her to facilitate safe driving. Convex mirrors are preferred because they always give an erect, though diminished, image. Also, they have a wider field of view as they are curved outwards. Thus, convex mirrors enable the driver to view a much larger area than would be possible with a plane mirror. Hence pair 4 is correctly matched.
• Convex Lens: A lens that has two spherical surfaces, bulging outwards. Such a lens is called a double convex lens. It is simply called a convex lens. It is thicker in the middle as compared to the edges. Convex lens converges light rays. Convex lenses are used to ---
  • Correct farsightedness.
  • Magnifying glasses 
  • Multijunction solar cell
  • Microscope o Hence pair 2 is correctly matched.
• Concave Lens: A lens that is bounded by two spherical surfaces, curved inwards is called a double concave lens or simply called a concave lens. It is thicker at the edges than at the middle. Such lenses diverge light rays. So it is also called diverging lenses. Concave lenses are used to ---
  • Correct Nearsightedness.
  • Peepholes
  • Flashlight
  • Camera

Hence pair 1 is correctly matched.

• Recently, the Supreme Court (SC) held that charge sheet by probing agency is not a “public document”. It stated that putting it in public domain will violate the rights of victim, accused and investigating agencies. SC said that If all the chargesheets and relevant documents produced along with the chargesheets are put on the public domain or the websites of the state governments, it will be contrary to the scheme of the Code of Criminal Procedure (CrPC).
• Charge sheet refers to a formal police record showing the names of each person brought into custody, the nature of the accusations, and the identity of the accusers. Hence, statement 1 is not correct. It is also known as four-part charging instrument containing: 
  • Information about the accused and the witnesses;
  • the charges and specifications;
  • the preferring of charges and their referral to a summary;
  • For the trial record.
• First Information Report (FIR) is a written document prepared by the police when they receive information about the commission of a cognizable offence. Based on information so provided the investigation started. F.I.R can also be registered by the Judicial Magistrate by giving the direction to the concerned jurisdictional area of the Police Station.Evidentiary value of F.I.R is that F.I.R is not substantive evidence in nature. But It can be used as corroborative or contradictory evidence. Hence, statement 2 is not correct.
• A charge sheet is distinct from the First Information Report (FIR), which is the core document that describes a crime that has been committed. It usually refers to one or more FIRs and charges an individual or organization for (some or all of) the crimes specified in those FIR(s). Once the charge sheet has been submitted to a court of law, prosecution proceedings against the accused begin in the judicial system.
• Under Youth Bar Association Case (2016) the SC issued directions to the police to upload the FIRs in website within 24 hours except in sensitive cases like rape.
• SC said that Putting the FIR on the website cannot be equated with putting the chargesheets along with the relevant documents on the public domain and the websites of the state governments.

• Organisms that can cause disease are found in a wide range of such categories of classification. Some of them are viruses, some are bacteria, some are fungi, some are single-celled animals or protozoans. Some diseases are also caused by multicellular organisms, such as worms of different kinds.
• Disease caused by Bacteria:
  • Whooping Cough - It is caused by a bacterium called Bordetella pertussis.
  • Diphtheria - It is caused by Corynebacterium diphtheriae.
  • Cholera - It is caused by Vibrio cholera. o Leprosy - It is caused by Mycobacterium leprae.
  • Pneumonia- It is caused by Streptococcus pneumonia.
  • Tetanus - It is caused by Clostridium tetani.
  • Typhoid - It is caused by Salmonella typhi.
  • Tuberculosis - It is caused by Mycobacterium tuberculosis.
  • Plague - It is caused by Yersinia pestis.
• Disease Caused by Protozoans:
  • Diarrhoea: There are a number of intestinal protozoa that cause diarrhea, but Entamoeba histolytica, Giardia intestinalis and Cryptosporidium species are the most important causes of diarrhea
  • Malaria: It is spread by Anopheles mosquitoes. The Plasmodium parasite that causes malaria is neither a virus nor a bacteria.
  • Amoebic dysentery: It is caused by Entamoebahistolytica.
  • Sleeping sickness: It is caused by Trypanosomabrucei.
  • Kala-azar It is caused by Leishmaniadonovani.
• Disease Caused by Worms:
  • Tapeworm: They are intestinal parasites. It cannot live on its own. It survives within the intestine of an animal including a human.
  • Pinworm: It is caused by a small, thin, white roundworm called Enterobiusvermicularis.
• Disease caused by Viruses:
  • Chickenpox - It is caused by the Varicella-zoster virus.
  • Small Pox - It is caused by the Variola virus.Common Cold -It is caused by Rhinovirus.
  • AIDS (Acquired Immuno Deficiency Syndrome) - It is caused by Human Immunodeficiency Virus (HIV).
  • Measles -It is caused by the Measles virus.
  • Mumps -It is caused by the Mumps virus.
  • Rabies - It is caused by the Rabies virus (Rhabdoviridae family).
  • Dengue fever -It is caused by the Dengue virus.
  • Viral encephalitis - It is an inflammation of the brain. It is caused by the rabies virus, Herpes simplex, poliovirus, measles virus, and JC virus.

Hence, option (b) is the correct answer.

• Sodium benzoate is an odorless, crystalline powder made by combining benzoic acid and sodium hydroxide. Benzoic acid is a good preservative on its own, and combining it with sodium hydroxide helps it dissolve in products. It is also used as a preservative in soft drinks to increase the acidity of flavor. Hence, statement 1 is correct.
• Aside from its use in processed foods and beverages, sodium benzoate is also added to some medicines, cosmetics, personal care products, and industrial products.
• While sodium benzoate is considered safe, scientific research has shown that negative side effects occur when it's mixed with ascorbic acid (vitamin C). Their studies indicate that it then turns into benzene, a known carcinogen that may cause cancer. Hence, statement 2 is correct.

• When a sealed transparent plastic bottle filled with hot air is placed in the freezer, the plastic bottle will collapse on itself. The collapsing bottle demonstrates the properties of gasses collectively known as the Ideal Gas Law, an equation describing the relationship between temperature, pressure, and volume.
• According to Gas Law, the pressure and volume are inversely proportional to each other and both are proportional to temperature. So as the temperature decreased when the bottle filled with hot air is placed inside the freezer, the pressure decreased until the bottle gave in and collapsed (the volume decreased until the pressure equalized).

Hence, option (c) is the correct answer.

• Blood is a constantly circulating fluid providing the body with nutrition, oxygen, and waste removal.
• Blood is a special connective tissue consisting of a fluid matrix, plasma, and formed elements.
• Plasma is the liquid component of blood. Plasma makes up 55% of blood’s total volume.
• 90-92 per cent of plasma is water. The remaining 8 percent of plasma contains several key materials, including:
  • proteins
  • Immunoglobulins
  • electrolytes
• Plasma Proteins
  • Fibrinogen, globulins and albumins are the major proteins.
    • Fibrinogens are needed for clotting or coagulation of blood. Fibrinogen helps to reduce active bleeding, making it an important part of the blood-clotting process. If a person loses a lot blood, they’ll also lose plasma and fibrinogen. This makes it harder for blood to clot, which can lead to significant blood loss. Hence, statement 1 is correct.
    • Globulins primarily are involved in defense mechanisms of the body and defends our body from infections including bacteria, fungi, viruses and cancer cells. Hence, statement 2 is correct.
    • Albumin help in osmotic balance. It is vital for maintaining a balance of fluid, called oncotic pressure, in the blood. This pressure is what keeps fluid from leaking into areas of the body and skin where less fluid usually collects. For example, people with low albumin levels may have swelling in their hands, feet, and abdomen. Hence, statement 3 is correct.
• ImmunoglobulinsPlasma contains gamma globulins, a type of immunoglobulin. Immunoglobulins help the body fight off infections.
• ElectrolytesElectrolytes conduct electricity when dissolved in water, hence their name. Common electrolytes include sodium, potassium, magnesium, and calcium. Each of these electrolytes plays a key role in the body.

E-cigarettes:

• E-cigarettes are electronic devices designed to simulate the act of smoking tobacco cigarettes.
• They are also called “e-cigs,” “vapes,” “e-hookahs,” “vape pens,” and “Electronic Nicotine Delivery Systems (ENDS).”
• Contain a heating element that vaporizes a liquid (e-liquid) which typically includes nicotine, flavorings, and other chemicals.
• Come in various forms, including pens, mods, tanks, and pod systems.
• Vaping is the act of inhaling and exhaling the aerosol produced by an e-cigarette.

The Central government has approved a new treatment regimen for leprosy, aiming to stop its transmission at the sub-national level by 2027.

Three-drug regimen:

• The WHO has recommended this treatment regimen in 2015.
• It consists of three drugs — dapsone, rifampicin and clofazimine. The combination is referred to as MDT (multidrug therapy). MDT kills the pathogen and cures the patient.
• This regimen is known as ‘Uniform MDT’, where a single three-pack kit can be given to all leprosy patients. This measure facilitates ease of administration.
• The duration of treatment is six months for PB and 12 months for MB cases

Mpemba effect is named after Tanzanian student Erasto Mpemba, who brought attention to this counterintuitive phenomenon in 1969.

• Aristotle, Francis Bacon, and René Descartes had noticed the effect centuries earlier.
• The effect is that hot water can freeze faster than cold water in similar conditions.

Recently, China launched the Einstein Probe (EP), a new astronomical satellite, for the observation of cosmic phenomena like black holes, colliding neutron stars, and exploding stars.

About

• The probe is named after Einstein for his theory of general relativity on black holes and gravitational waves.
• The probe will be used to search for X-ray signals accompanying gravitational wave events around the celestial bodies and to pinpoint them.
• The Einstein Probe was launched using the “Long March-2C carrier rocket”.
• The satellite is shaped like a lotus in full bloom. The lotus-inspired design incorporates 12 ‘petals’ housing wide-field X-ray telescopes (WXT) and two ‘stamens’ containing follow-up X-ray telescopes (FXT).

International Collaboration

• Einstein Probe is a collaboration led by the Chinese Academy of Sciences (CAS) with the European Space Agency (ESA) and the Max Planck Institute for Extraterrestrial Physics (MPE), Germany.

Statement 1 is not correct and statement 2 is correct.

Advantages of LEDs

• Long Lifespan: LED bulbs can last up to 25,000 hours or more, which means less frequent replacements and reduced maintenance costs. o LEDs have an extremely long lifespan relative to every other lighting technology (including fluorescent lights).
• Energy Efficiency: They convert a higher percentage of electrical energy into light, reducing energy waste and lowering electricity bills.
• LEDs can produce up to 300 lumen (amount of visible light emitted per second) versus incandescent bulbs’ 16 lumen and fluorescent lamps’ 70 lumen.

Human papillomavirus (HPV):

• HPV is the name of a very common group of viruses that affects skin. They do not cause any problems in most people, but some types can cause genital warts or cancer.

• Symptoms: HPV does not usually cause any symptoms. Most people who have it do not realise and do not have any problems. But sometimes the virus can cause painless growths or lumps around vagina,penis or anus (genital warts)

Square Kilometre Array Observatory

• The SKA Observatory is an intergovernmental organization bringing together 14 countries; Australia, Canada, China, France, Germany, India, Italy, New Zealand, Spain, South Africa, Sweden, Switzerland, The Netherlands and the United Kingdom.
• Headquarters: United Kingdom
• Mandate: Its aim is to build and operate cutting-edge radio telescopes to transform the understanding of the Universe.
  • It will explore the formation and evolution of galaxies, fundamental physics in extreme environments and the origins of life.
• The observatory consists of the two telescopes at radio-quiet sites in South Africa and Australia, and associated facilities to support the operations of the telescopes. Indian Engagement in SKAO
• India, through the Pune-based National Centre for Radio Astrophysics (NCRA) has been involved in the development of SKA since its inception in the 1990s.
• India’s main contribution is in the development, and operation, of the Telescope Manager element, the “neural network” or the software that will make the telescope work.

Statement 1 is correct: Radiocarbon dating, or carbon-14 dating, is a scientific method that can accurately determine the age of organic materials.

• It was developed in the late 1940s by Willard Libby, the technique is based on the decay of the carbon-14 isotope.

Statement 2 is not correct: It starts with cosmic rays—subatomic particles of matter that continuously rain upon Earth from all directions.

• When cosmic rays reach Earth’s upper atmosphere, physical and chemical interactions form the radioactive isotope carbon-14.
• Living organisms absorb this carbon-14 into their tissue. Once they die, the absorption stops, and the carbon-14 begins very slowly to change into other atoms at a predictable rate.

By measuring how much carbon-14 remains, scientists can estimate how long a particular organic object has been dead.

Key Points

• Prithvi was the first Indian missile.
• It was a surface-to-surface ballistic missile.
• It was inducted into the Forces Command in 2003.
• It was developed under the Integrated Guided Missile Development Program (IGMDP).
• It was developed by Defence Research Development Organization.
• Dr A.P.J. Abdul Kalam was the brain behind this project.
• He was the former President of India, famously known as the Missile Man of India.

Key Points

• According to Union Minister of State for Space Jitendra Singh, India's first human space flight mission under the 'Gaganyaan program' is scheduled to launch in the fourth quarter of 2024.
• Gaganyaan, India's first human space mission, is set to launch in 2024.
• Two uncrewed Gaganyan missions, uncrewed mission 'G1'(in the last quarter of 2023) and the second uncrewed mission 'G2' in the second quarter of 2024
• The second mission will carry "Vyommitra", a spacefaring human-robot developed by ISRO, in the second quarter of 2024.

Important Points

• India will become the fourth nation in the world to launch a Human Spaceflight Mission after USA, Russia and China.
• The major missions viz., Test vehicle flight for the validation of Crew Escape System performance and the 1st Uncrewed mission of Gaganyaan (G1) are scheduled during the beginning of 2nd half of 2022. 
• The astronaut training facility is getting established in Bengaluru and in advanced stage of completion.
• Basic Aeromedical training and flying practice completed as part of the Indian leg of training.
• The design of all systems of Gaganyaan has been completed. 
• The configuration and design of ground infrastructure have been completed and modifications needed are being implemented.

Important Points

• A team of engineers at the Indian Institute of Science (IISc) had developed an intensive care unit (ICU) grade ventilator under the name of ‘Project Praana’.
• Recently, the team has successfully completed the prototyping of the ventilator, which is now in the process of being commercialised.
• The affordable ventilator uses only components made in India or components which are easily available in the domestic markets.
• The team developed the ventilator in a record 35 days.

It is a respiratory disease caused by virus that is endemic in pigs. The symptoms are the same as the seasonal flu -- cough, sore throat, and body aches. Swine flu is transmitted from person to person by inhalation or ingestion of droplets containing virus from people sneezing or coughing; it is not transmitted by eating cooked pork products. The recent outbreak of swine flu in India is due to influenza virus H1N1.

Union Home Minister Shri Amit Shah has decided to launch a web portal ‘MySecurity.in’ that will be a platform for innovation in the field of security related web applications. Any individual, company, student, NGO etc can develop and deploy on this portal such security applications which may be useful to the people. It will enable the general public to get access to a large number of security related applications.

The main objective of launching the web portal ‘MySecurity.in’ is to promote innovation in developing security related applications as well as offer to the people safe and trusted applications for their security needs. People will have options to choose the applications best suited for their requirements. Application developers, meeting the basic screening criteria, will be allowed hardware and middleware resources in a cloud based environment to deploy their applications. An expert group constituted by MHA will also evaluate the application on parameters like usefulness, innovation, public acceptance, technology used, maintenance, updation, feedback mechanism etc.

NASA-ISRO Synthetic Aperture Radar (NISAR) mission will be launched in 2020. Its purpose is to measure the changes on earth’s land surface, ice surface, glaciers, earthquakes and volcanoes. The data will be used to understand climate change and predict natural disasters. NISAR will be the first satellite mission to use two different radar frequencies (L-band and S-band). Hence it can capture resolution even less than a centimeter of earth’s surface.

Encephalitis is an inflammation of the brain. Japanese encephalitis is a disease caused by the mosquito-borne Japanese encephalitis virus. The Japanese encephalitis virus is a virus from the family Flaviviridae. Domestic pigs and wild birds (especially herons) are reservoirs of the virus; transmission to humans may cause severe symptoms. The symptoms include high fever, headache, vomiting, confusion and, in severe cases, seizures, paralysis and coma. The disease can result in brain damage. Children and elderly people are especially at risk of developing a severe form of encephalitis. Mortality of this disease varies but is generally much higher in children.

Ballast water is used in ships for stability purpose.

The Department of Science & Technology, Ministry of Science & Technology has been entrusted with the responsibility of coordinating two out of eight national missions launched under the National Action Plan on Climate Change (NAPCC). These are National Mission for Sustaining Himalayan Ecosystem (NMSHE) and National Mission on Strategic Knowledge for Climate Change (NMSKCC).