Daily Quiz: UPSC Prelims Marathon: June 8

Explanation-

Blood group is determined by the antigen present on RBC. As you can see, blood group A has only antigen A on RBCs. Therefore, baby of both the parents will either have antigen A on its blood cells or no antigen on it because antigen B is absent in both the parents.

Thus, either it will have blood group A or O. It can not have blood group B or AB.

Explanation– 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.

You can see biodigester toilet below in image

Explanation– Line of sight communication is a type of propagation of signals that can transmit and receive data only where transmit and receive stations are in view of each other without any sort of an obstacle between them.

NFC or near field communication, Wifi and Bluetooth don’t require such line of sight. FM radio, microwave and satellite transmission are examples of line-of-sight communication

Explanation– Statement 1 is wrong as in osmosis solvent molecules moves from low concentration solution to higher concentration solution through a semipermeable membrane.

Statement 2 is also wrong as in reverse osmosis external pressure is applied to the higher concentration solution. SOlvent in this case move from concentrated solution to dilute solution. External pressure applies is above the osmotic pressure.

Explanation– 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

Explanation– Minamata diseases is caused by mercury poisoning. Blue baby syndrome is caused by nitrate contamination of groundwater and itai itai is cadmium poisoning disease. Only blue baby syndrome is correctly matched, hence ans is C.

Explanation– The separation of visible light into its different colors is known as dispersion. As you can see in above figure, all three phenomenon happens when a rainbow is formed

Explanation– Statement 1 is wrong. Ionosphere contains charged particles due to which electromagnetic radio waves gets reflected and communication becomes possible. It is not due to ozone. Ozone is found mainly in Stratosphere and in traces in troposphere. It’s main function is absorption of  UV rays. Statement 2 is right. You can see wavelength of Radio waves is in metres to kilometres