UPSC Prelims 2012 Analysis

Explanation

Capillarity, or capillary action, is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity.

Capillary action allows the kerosene to rise up the wick, where it can then be ignited.

Drinking with a straw relies on the principle of air pressure rather than capillarity. When you suck the air out of the straw, you create a pressure difference that forces the drink into the straw.

Blotting paper absorbs ink or any liquid due to capillary action, where the liquid is drawn into the small pores of the blotting paper.

Capillary action is critical for transporting water from the roots to the leaves of tall trees against the force of gravity.

Explanation

Genetically engineered plants have been created for various purposes beyond just resistance to pests.

They have been developed to enable them to withstand drought by introducing genes that help the plants conserve water or tolerate dry conditions. This allows them to survive better in drought-prone areas.

Another prospect is to increase the nutritive value of the produce. This can involve enhancing the plants with additional nutrients or higher protein content to improve the overall nutritional quality of the crop.

Increasing the shelf life of produce is also a common goal for genetic engineering to reduce food waste and improve storage capabilities.

While the idea of enabling plants to grow and do photosynthesis in spaceships and space stations is a futuristic concept, it is not a current application of genetically engineered plants.

Therefore, the correct answer is 1, 2 and 4.

Explanation

The creation of antimatter, specifically the anti-helium nucleus, has significant implications in the field of astrophysics and cosmology.

It does not directly contribute to making mineral prospecting and oil exploration easier and cheaper.

However, it does help in probing the possibility of the existence of stars and galaxies made of antimatter. This is because antimatter is the 'opposite' of normal matter, and its existence could imply the existence of antimatter celestial bodies.

Additionally, understanding antimatter and its properties can contribute to our understanding of the evolution of the universe, as it plays a role in the theories and models that describe the universe's history and future.

Therefore, the implications of the creation of antimatter are that it will help probe the possibility of the existence of stars and galaxies made of antimatter and it will help understand the evolution of the universe.

Explanation

Lead is a toxic metal that can cause serious health problems if ingested or inhaled. It is found in various sources, even after its addition to petrol has been banned.

Smelting units are one of the significant sources of lead exposure. During the smelting process, lead is released into the environment, which can be inhaled or ingested.

Paints, especially those used in older houses, can contain lead. When the paint peels or cracks, lead dust can be released into the environment.

However, pens and pencils, as well as hair oils and cosmetics, are not typically sources of lead poisoning.

Therefore, the correct answer includes smelting units and paints.

Explanation

UV radiation can effectively inactivate or kill various harmful microorganisms, such as bacteria, viruses, and protozoa, by damaging their genetic material. This makes it an effective method for disinfecting water and eliminating waterborne pathogens.

UV radiation does not directly remove undesirable odours from water. Odour removal from water typically involves other treatment processes, such as activated carbon filtration, aeration, or chemical treatment.

UV radiation does not have a direct effect on the sedimentation of solid particles, removal of turbidity, or improving the clarity of water. These aspects are typically addressed by other physical and chemical water treatment processes, such as coagulation, flocculation, and filtration.

Explanation

Biopesticides are certain types of pesticides derived from natural materials such as animals, plants, bacteria, and certain minerals. Bacteria, fungi, and flowering plants all have species that are used as biopesticides.

Bacteria like Bacillus thuringiensis produce proteins that are toxic to certain insects. Fungi can also be used as biopesticides as they can infect and kill insects. Flowering plants can produce compounds that are toxic to certain pests and can be used as biopesticides.

Explanation

Graphene is renowned for its excellent electrical conductivity, which stems from its two-dimensional, one-atom-thick structure.

Graphene is famously strong for its very thin structure, making it one of the strongest materials known.

Graphene is made entirely of carbon, arranged in a hexagonal lattice. While it does have high optical transparency, its composition is carbon, not silicon.

Its electrical conductivity, along with its optical transparency, makes graphene an excellent candidate for use in conducting electrodes for various display technologies.

So, statements 1, 2 and 4 are correct.

Explanation

Stem cells can be derived from various sources, including not just mammals, but also other vertebrates like birds and fish, as well as some invertebrates.

Stem cells provide a powerful tool for drug screening and toxicology studies. They can be used to generate specific types of cells that are targeted by drugs, allowing researchers to evaluate the efficacy and safety of new pharmaceutical compounds before proceeding to clinical trials.

Stem cells have the potential to be used in regenerative medicine to repair or replace damaged tissues and organs. This includes a wide range of applications, from bone marrow transplants (a well-established stem cell therapy for certain blood disorders) to experimental treatments for neurodegenerative diseases, heart disease, diabetes, and more.

Explanation

Thorium fuel generates no new bomb-usable material in the waste profile; the waste consists of the radioisotope Uranium-233, or U233, which is virtually impossible to weaponize.

Thorium fuel will generate more energy per unit of mass than uranium fuel by a factor of approximately 30.

Thorium is four times more abundant in nature than uranium and is widely distributed throughout the Earth's crust.

All the statements in this question are correct.

Explanation

The resistance to the introduction of Bt brinjal in India is due to several reasons.

Firstly, there is a concern that the consumption of Bt brinjal may have an adverse impact on health. This is due to the fact that it has been genetically modified, and there is still ongoing debate and research about the long-term health effects of consuming genetically modified organisms.

Secondly, there is a concern that the introduction of Bt brinjal may have an adverse effect on biodiversity. This is because the introduction of a genetically modified organism into an ecosystem could potentially disrupt the balance of species and have unforeseen consequences.

The statement about Bt brinjal being created by inserting a gene from a soil fungus into its genome is true, but it is not a reason for resistance.

The statement about the seeds of Bt brinjal being terminator seeds is also not a reason for resistance as Bt brinjal seeds are not terminator seeds. Terminator seeds are genetically modified to be sterile after the first generation, which is not the case with Bt brinjal.

Explanation

Electrically charged particles from space, such as those from the solar wind or cosmic rays, are indeed potentially harmful to living organisms.

The Earth's magnetic field plays a crucial role in protecting the surface by diverting these charged particles toward its poles. This phenomenon is responsible for the creation of the auroras the Northern and Southern Lights (Aurora Borealis and Aurora Australis, respectively).

When these charged particles are funneled toward the Earth's poles by its magnetic field, they interact with molecules in the Earth's atmosphere, creating the beautiful light displays rather than causing harm to living beings on the surface.

Explanation

The key evidence cited by scientists for the continued expansion of the universe is the observation of the redshift phenomenon in light from distant galaxies.

As the universe expands, the wavelengths of light from these galaxies are stretched, resulting in a shift towards longer, redder wavelengths - the redshift phenomenon. This redshift is considered a strong piece of evidence supporting the expansion of the universe, as predicted by the models of cosmology.