Daily Quiz: UPSC Prelims Marathon- July 20

None of the above statements is correct.

Statement 1 is incorrect. LaWS operates within an invisible part of the electromagnetic spectrum. It is absolutely silent and incredibly effective. It strikes are extremely accurate, silent and invisible. It is primarily intended to take on drones, aircraft, and small vessels that could be used in an attack.

Statement 2 is incorrect. It is a very versatile weapon that can be used against a variety of targets in air or surface targets or ground-based targets.

Statement 3 is incorrect. Each strike of the system travels 50,000 times the speed of an incoming ICBM (Intercontinental Ballistic Missile).

Why is it in news?

United States has successfully tested the world’s first-ever active Laser Weapons System (LaWS).

Option d is the correct answer.

Both the spheres will reach the ground simultaneously. How? Discuss in the comment section 🙂

The thymus gland, located behind your sternum and between your lungs, is only active until puberty. After puberty, the thymus starts to slowly shrink and become replaced by fat.

Thymosin is the hormone of the thymus, and it stimulates the development of disease-fighting T cells.

The thymus gland will not function throughout a full lifetime, but it has a big responsibility when it’s active—helping the body protect itself against autoimmunity, which occurs when the immune system turns against itself. Therefore, the thymus plays a vital role in the lymphatic system (your body’s defense network) and endocrine system.

Before birth and throughout childhood, the thymus is instrumental in the production and maturation of T-lymphocytes or T cells, a specific type of white blood cell that protects the body from certain threats, including viruses and infections. The thymus produces and secretes thymosin, a hormone necessary for T cell development and production.

The thymus is special in that, unlike most organs, it is at its largest in children. Once you reach puberty, the thymus starts to slowly shrink and become replaced by fat. By age 75, the thymus is little more than fatty tissue. Fortunately, the thymus produces all of your T cells by the time you reach puberty.

Statement 2 is wrong. Pipes are painted black and not white to enable maximum absorption of sunlight. Statement 1 and 2 are correct.

What is solar water heating?

Solar water heating collectors capture and retain heat from the sun and transfer this heat to a liquid. Solar thermal heat is trapped using the “greenhouse effect,” in this case is the ability of a reflective surface to transmit short wave radiation and reflect long wave radiation. Heat and infrared radiation (IR) are produced when short wave radiation light hits a collector’s absorber, which is then trapped inside the collector. Fluid, usually water, in contact with the absorber collects the trapped heat to transfer it to storage.

Biodigester toilets use anaerobic bacteria like Clostridium and Methanosarcina. Anaerobic bacteria don’t need oxygen to carry out biochemical reactions. They were found in Antarctica when DRDO sent scientists  under India’s 13th Antarctic Mission in 1994 to look for microorganisms that can break down excreta. This was required for the military posted in higher altitude snow covered areas where deep pits were dug out and all excreta was collected. Afterwards it was dropped in plains or incinerated which required labor, cost and did pollution. Biodigester solved all this problem.

Excreta or faecal matter contains carbohydrates, protein and fats. In the first step, bacteria converts them into simple sugars, amino acids and fatty acids. In the next step, these break to form carbonic acid, alcohols, hydrogen and water. In the third step, acetic acid, hydrogen and carbon dioxide is formed and finally methane, carbon dioxide and water are formed. Methane can be used for cooking while water for irrigation. These series of stepss are called as- hydrolysis, acidogenesis, acetogenesis and methanogenesis.

These toilets don’t require any sewerage system and once bacteria are embedded in biodigesters, they can work for very long time without maintenance.

Hence statement 2 and 3 are correct.

Hard water is that water which contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates. Ferrous iron may also be present in this water. This hardness is of two types, temporary and permanent.

Hardness that is caused by calcium bicarbonate is known as temporary, because boiling converts the bicarbonate to the insoluble carbonate; hardness from the other salts is called permanent.

This hard water is unfit for drinking as salt presents reacts with acids in stomach and cause digestive disorders.

These salts of hard water forms an insoluble gelatinous curd on reaction with soap and lather formation doesn’t occur and as such they are not fit for washing clothes even.

This water is unsuitable for boilers as calcium and magnesium in hard waters form a hard, adherent scale on the plates. As a result fuel consumption is increased, and the boiler deteriorates rapidly through increased external overheating.

Hard water is unsuitable for crops as salts present disturbs the normal chemistry of soil and clogs the irrigation channel pathways of plants.

Green muffler involves growing green plants along roadsides to reduce noise pollution. Thus, option c is correct.

Green muffler is a control measure of noise pollution by planting green plants ,normally 4-5 rows of plants are grown near the noisy places like roadsides and industrial areas so that they can obstruct noise reaching citizens.