Test: Science & Technology- 4 - UPSC MCQ

Superconductivity is a state in which a material shows absolutely zero electrical resistance. While resistance is a property that restricts the flow of electricity, superconductivity allows unhindered flow.

In a superconducting state, the material offers no resistance at all. All the electrons align themselves in a particular direction, and move without any obstruction in a “coherent” manner.

Because of zero resistance, superconducting materials can save huge amounts of energy, and be used to make highly efficient electrical appliances.

Two fundamental properties of a superconductor:

• Zero resistance to electrical current.
• Diamagnetism

Diamagnetism is a property opposite to normal magnetism that we are used to. A diamagnetic substance repels an external magnetic field, in sharp contrast to normal magnetism, or ferromagnetism, under which a substance is attracted by an external magnetic field.

Measles is a highly contagious viral disease.

Measles is transmitted via droplets from the nose, mouth or throat of infected persons.
Initial symptoms, which usually appear 10–12 days after infection, include high fever, a runny nose, bloodshot eyes, and tiny white spots on the inside of the mouth. Several days later, a rash develops, starting on the face and upper neck and gradually spreading downwards.

Vulnerability: Severe measles is more likely among poorly nourished young children, especially those with insufficient vitamin A, or whose immune systems have been weakened by HIV/AIDS or other diseases.

The most serious complications include blindness, encephalitis (an infection that causes brain swelling), severe diarrhoea and related dehydration, and severe respiratory infections such as pneumonia.

Prevention: Routine measles vaccination for children, combined with mass immunization campaigns in countries with low routine coverage, are key public health strategies to reduce global measles deaths.

Sounding rockets are one or two stage solid propellant rockets used for probing the upper atmospheric regions and for space research

They also serve as easily affordable platforms to test or prove prototypes of new components or subsystems intended for use in launch vehicles and satellites.

The launch of the first sounding rocket from Thumba near Thiruvananthapuram, in 1963, marked the beginning of the Indian Space Programme. Sounding rockets made it possible to probe the atmosphere in situ using rocket-borne instrumentation.

Some of the harm chemical fertilizers may cause include waterway pollution, chemical burn to crops, increased air pollution, acidification of the soil and mineral depletion of the soil.

Chemical fertilizers are high in nutrient content such as nitrogen. Over-application of chemical fertilizer to plants may cause the leaves to turn yellow or brown, damaging the plant and reducing crop yield. This condition is known as chemical leaf scorch. Leaf scorch can cause the leaves of the plant to wither and may cause the plant to die.

When soil is too acidic, it is treated with bases like quick lime (calcium oxide) or slaked lime (calcium hydroxide). If the soil is basic, organic matter is added to it. Organic matter releases acids which neutralises the basic nature of the soil.

The government has declared ocean energy as Renewable Energy.

Accordingly, the Ministry of New and Renewable Energy has clarified that energy produced using various forms of ocean energy such as tidal, wave, ocean thermal energy conversion etc. shall be considered as Renewable Energy and shall be eligible for meeting the non-solar Renewable Purchase Obligations (RPO).

Osmotic energy: This technique produces energy from the movement of water across a membrane between a saltwater reservoir and freshwater reservoir.

A microbial fuel cell (MFC) is a bio-electrochemical device that harnesses the power of respiring microbes to convert organic substrates directly into electrical energy.

At its core, the MFC is a fuel cell, which transforms chemical energy into electricity using oxidation reduction reactions. The key difference of course is in the name, microbial fuel cells rely on living biocatalysts to facilitate the movement of electrons throughout their systems instead of the traditional chemically catalyzed oxidation of a fuel at the anode and reduction at the cathode.

A MFC consists of an anode and a cathode separated by a cation specific membrane. Microbes at the anode oxidize the organic fuel generating protons which pass through the membrane to the cathode, and electrons which pass through the anode to an external circuit to generate a current. The trick of course is collecting the electrons released by bacteria as they respire.

Gas hydrates are naturally occurring, solid compounds containing natural gas (mainly methane) and water. Methane gas hydrate is stable at the seafloor at water depths beneath about 500 m.

Scientific interest in gas hydrates is driven mainly by its potential future role as an energy resource, and by the role of methane as a strong greenhouse gas and contributor to global climate change.

The sources and processes by which hydrogen is derived, are categorised by colour tabs.

Hydrogen produced from fossil fuels is called grey hydrogen; this constitutes the bulk of the hydrogen produced today.

Hydrogen generated from fossil fuels with carbon capture and storage options is called blue hydrogen;

Hydrogen generated entirely from renewable power sources is called green hydrogen. In the last process, electricity generated from renewable energy is used to split water into hydrogen and oxygen.

On January 31, Stardust 1.0 was launched from Loring Commerce Centre in Maine, US, becoming the first commercial space launch powered by biofuel, which is non-toxic for the environment as opposed to traditionally used rocket fuels.

Biofuels are obtained from biomass, which can be converted directly into liquid fuels that can be used as transportation fuels. The two most common kinds of biofuels in use today are ethanol and biodiesel and they both represent the first generation of biofuel technology.

Ethanol, for instance, is renewable and made from different kinds of plant materials. Biodiesel on the other hand is produced by combining alcohol with new and used vegetable oils, animal fats or recycled cooking grease.

Noise-cancelling headphones (a smart wearable device) can be broken down into two main groups: passive and active.

Passive headphones simply reduce background noise by using insulating materials to prevent external noise from entering the ear.

Active headphones, on the other hand, are a little more complex.

Many active headphones have an external microphone that screens incoming sounds. When the microphone detects unwanted noise—such as a humming airplane engine—it sends a sound wave into the headphone speakers that is 180 degrees out of phase with the bothersome sound. Consequently, the two waves cancel each other out, resulting in silence. Unlike traditional earbuds or headphones, noise-cancelers require a rechargeable battery to send out the mirror waves.

Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis.

Microbiological confirmation on sputum, chest x-ray screening etc. are some of the methods used to screen TB.

Using NASA’s James Webb Space Telescope as a sort of time machine, researchers plan to investigate how new stars are born, with the help of a natural phenomenon called “gravitational lensing”.

• Gravitational lensing is an effect of Einstein’s theory of general relativity – simply put, mass bends light.
• The gravitational field of a massive object will extend far into space, and cause light rays passing close to that object (and thus through its gravitational field) to be bent and refocused somewhere else.
• The more massive the object, the stronger its gravitational field and hence the greater the bending of light rays – just like using denser materials to make optical lenses results in a greater amount of refraction.

Gravitational lensing is useful to cosmologists because it is directly sensitive to the amount and distribution of dark matter.

Lensing can help astronomers work out exactly how much dark matter there is in the Universe as a whole and also how it is distributed.

Lensing has also been used to help verify the existence of dark matter itself.

India’s first indigenously developed high-temperature based Fuel Cell System. It is a 5.0 kW fuel cell system that generates power in a green manner.

It takes methanol as the input and produces heat and water as its bi-products

The developed fuel cells are based on High-Temperature Proton Exchange Membrane (HTPEM) technology.

• Developed under the Public-Private Partnership (PPP) model by the Council of Scientific and Industrial Research (CSIR) in partnership with Indian industries.
• Built under India’s flagship programme named ‘New Millennium Indian Technology Leadership Initiative (NMITLI)’.

Applications:

• Suitable for distributed stationary power applications like; for small offices, commercial units, data centers etc.; where highly reliable power is essential with simultaneous requirement for air-conditioning.
• It will also meet the requirement of efficient, clean and reliable backup power generator for telecom towers, remote locations and strategic applications as well.
• Replace Diesel Generating (DG) sets and help reduce India’s dependence on crude oil.

With the depletion of ozone layer, more UV radiation filters into troposphere. UV radiations lead to ageing of skin, cataract, sunburn and skin cancer in humans.

Many phytoplankton cannot tolerate the bright, unfiltered solar radiation at the ocean’s surface and are impaired especially by the high-energy, short-wavelength radiation in the UV range of the spectrum.

UV-B impairs photosynthesis in many species. Overexposure to UV-B reduces size, productivity, and quality in many of the crop plant species. UV-B increases plants’ susceptibility to disease by sometimes causing mutations or damaging plant proteins.

Agricultural lime, also called aglime, is a soil additive made from pulverized limestone or chalk.

The primary active component is calcium carbonate.

The effects of agricultural lime on soil are:

• it increases the pH of acidic soil (the lower the pH the more acidic the soil); in other words, soil acidity is reduced and alkalinity increased
• it provides a source of calcium and magnesium for plants
• it permits improved water penetration for acidic soils
• it improves the uptake of major plant nutrients (nitrogen, phosphorus, and potassium) of plants growing on acid soils

Cholera would not be possible without osmosis. The choleric bacteria populate in our intestines and begin to reverse the intestinal cells’ ionic orientation. In other words, it changes the way ions and, subsequently, water is transported in our intestines.

when our ions’ orientations are switched, the intestinal cells are no longer able to absorb water into the body. It actually flows out. Now osmosis happens in the other direction and water moves from our intestinal cells into our intestines. This is what causes cholera’s deadly watery diarrhoea.

This is why cholera can kill you so quickly, because it does not rely on how much water you consume.

The James Webb Space Telescope is a joint NASA-ESA-CSA space telescope that is planned to succeed the Hubble Space Telescope as NASA’s flagship astrophysics mission.

The JWST has four key goals:

• to search for light from the first stars and galaxies that formed in the Universe after the Big Bang
• to study the formation and evolution of galaxies
• to understand the formation of stars and planetary systems
• to study planetary systems and the origins of life.

A blockchain is, in the simplest of terms, a time-stamped series of immutable record of data that is managed by cluster of computers not owned by any single entity. Each of these blocks of data (i.e. block) are secured and bound to each other using cryptographic principles (i.e. chain).

The blockchain network has no central authority — it is the very definition of a democratized system. Since it is a shared and immutable ledger, the information in it is open for anyone and everyone to see.

A blockchain carries no transaction cost. (An infrastructure cost yes, but no transaction cost.)

A ray passing through the principal focus of a concave mirror or a ray which is directed towards the principal focus of a convex mirror, after reflection, will emerge parallel to the principal axis.

So, concave mirrors are commonly used in torches, search-lights and vehicles headlights to get powerful parallel beams of light. They are often used as shaving mirrors to see a larger image of the face. The 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.

Carbohydrates are sugars that come in 2 main forms – simple and complex. This is also referred to as simple sugars and starches.

The difference between a simple and complex carb is in how quickly it is digested and absorbed – as well as it’s chemical structure.

Sugars are found in a variety of natural food sources including fruit, vegetables and milk, and give food a sweet taste. But they also raise blood glucose levels quickly.

Sugars can be categorised as single sugars (monosaccharides), which include glucose, fructose and galactose, or double sugars (disaccharides), which include sucrose (table sugar), lactose and maltose.

Complex carbohydrates, also known as polysaccharides, are starches formed by longer saccharide chains, which means they take longer to break down.

H9N2 is a subtype of the influenza A virus, which causes human influenza as well as bird flu.

An electric current always produces a magnetic field. Even weak ion currents that travel along the nerve cells in our body produce magnetic fields.

• When we touch something, our nerves carry an electric impulse to the muscles we need to use. This impulse produces a temporary magnetic field.
• These fields are very weak and are about one-billionth of the earth’s magnetic field. Two main organs in the human body where the magnetic field produced is significant, are the heart and the brain. The magnetic field inside the body forms the basis of obtaining the images of different body parts.
• This is done using a technique called Magnetic Resonance Imaging (MRI). Analysis of these images helps in medical diagnosis.

Photosynthesis is the process by which plants, some bacteria and some protistans use the energy from sunlight to produce glucose from carbon dioxide and water. This glucose can be converted into pyruvate which releases adenosine triphosphate (ATP) by cellular respiration. Oxygen is also formed.