Science & Technology Quiz: Science |6 Mar, 2021

As the wind energy industry expands and larger-scale projects are developed, wind turbines are becoming larger in rotor diameter as well as in hub height.

· Accordingly, it is becoming difficult to accurately assess the wind resource with standard cup anemometers mounted on standard height (60m) meteorological (met) towers.

· For this reason, attention is being directed to other methods of wind speed measurement, such as SODAR (Sonic Detection and Ranging).

· Since the SODAR can measure wind speed as a function of height and is relatively easy to transport and assemble, the technology is very appealing.

Source: NCERT

The strongest gravitational waves are produced by cataclysmic events such as colliding black holes, supernovae (massive stars exploding at the end of their lifetimes), and colliding neutron stars.

Other waves are predicted to be caused by the rotation of neutron stars that are not perfect spheres, and possibly even the remnants of gravitational radiation created by the Big Bang.

Source: NCERT

The process in which solids directly change to gases is known as sublimation.

· This occurs when solids absorb enough energy to completely overcome the forces of attraction between them.

· Dry ice and Camphor are examples of solids that undergo sublimation.

Source: NCERT

Nitrogen (N) forms oxides in which nitrogen exhibits each of its positive oxidation numbers from +1 to +5. Nitrous oxide (dinitrogen oxide), N2O, is formed when ammonium nitrate, NH4NO3, is heated.

· This oxide, which is a colourless gas with a mild, pleasant odour and a sweet taste, is used as an anesthetic for minor operations, especially in dentistry.

· It is called laughing gas because of its intoxicating effect. It is also widely used as a propellant in aerosol cans of whipped cream.

· Gaseous nitric oxide is the most thermally stable oxide of nitrogen and is also the simplest known thermally stable paramagnetic molecule—i.e., a molecule with an unpaired electron.

· It is one of the environmental pollutants generated by internal-combustion engines, resulting from the reaction of nitrogen and oxygen in the air during the combustion process.

Source: NCERT

Styrene is primarily a synthetic chemical. It is also known as vinyl benzene, ethenyl benzene, cinnamene, or phenyl ethylene.

· It’s a colorless liquid that evaporates easily and has a sweet smell. It often contains other chemicals that give it a sharp, unpleasant smell.

· It dissolves in some liquids but doesn’t dissolve easily in water. Billions of pounds are produced each year to make products such as rubber, plastic, insulation, fiberglass, pipes, automobile parts, food containers, and carpet backing.

· Most of these products contain styrene linked together in a long chain (polystyrene) as well as unlinked styrene.

· Low levels of styrene also occur naturally in a variety of foods such as fruits, vegetables, nuts, beverages, and meats.

Source: The Hindu

The only chemical elements created at the beginning of our universe were hydrogen, helium and lithium, the three lightest atoms in the periodic table. These elements were formed throughout the universe as a hot gas.

· Lithium makes up a mere 0.0007 percent of the Earth’s crust, according to the Jefferson Lab of USA, and it’s only found locked up in minerals and salts.

· Those salts have the power to change the brain: Lithium salts were the first drugs approved by the Food and Drug Administration to treat mania and depression, according to the National Institute of Mental Health.

Source: NCERT

Arthropods are everywhere and are the largest animal phylum — about 85% of all known animals in the world are part of this class.

· There are far more species of arthropods than there are species in all the other phylum’s (phyla) combined.

· They are spiders, insects, centipedes, mites, ticks, lobsters, crabs, shrimp, crayfish, krill, barnacles, scorpions and many, many others.

· Arthropods are cold blooded — which means, their body temperature depends on the temperature of the environment surrounding them.

Source: The Hindu

Unicellular Organisms.

· Bacteria are tiny, single-celled organisms that get nutrients from their environments.

· Fungi live as either single-celled organisms or multi-cellular organisms. Single-celled fungi are referred to as yeasts. The vast majority of fungi are multi-cellular. A fungus gets nutrition from plants, food, and animals in damp, warm environments.

· Protozoa are one-celled organisms, like bacteria. But they are bigger than bacteria and contain a nucleus and other cell structures, making them more like plant and animal cells.

Source: NCERT

Polarimetry is a sensitive, nondestructive technique for measuring the optical activity exhibited by inorganic and organic compounds.

· A compound is considered to be optically active if linearly polarized light is rotated when passing through it.

· A team of astronomers has discovered that the closest known brown dwarf, Luhman 16A, shows signs of cloud bands similar to those seen on Jupiter and Saturn.

· The researchers used an instrument on the Very Large Telescope in Chile to study polarised light from the Luhman 16 system. Polarisation is a property of light that represents the direction that the light wave oscillates.

· The polarimetry technique is not limited to brown dwarfs. It can also be applied to exoplanets orbiting distant stars. The atmospheres of hot, gas giant exoplanets are similar to those of brown dwarfs.

Source: The Hindu

A black hole is a place in space where gravity pulls so much that even light cannot get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.

· The largest black holes are called “supermassive.” These black holes have masses that are more than 1 million suns together. Scientists have found proof that every large galaxy contains a supermassive black hole at its center.

· The supermassive black hole at the center of the Milky Way galaxy is called Sagittarius A. It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths.

· Even if a black hole the same mass as the sun were to take the place of the sun, Earth still would not fall in.

· The black hole would have the same gravity as the sun. Earth and the other planets would orbit the black hole as they orbit the sun now.

· The sun will never turn into a black hole. The sun is not a big enough star to make a black hole.

Source: NCERT and The Hindu