CDS II - General Knowledge Previous Year Question Paper 2016 - CDS MCQ

• Landfill gas is a complex mix of different gases created by the action of microorganisms within a landfill.
• Landfills depend on the nature of the waste.
• The dominant process in most landfills is the third process whereby anaerobic bacteria decompose organic waste to produce biogas, which consists of methane and carbon dioxide together with traces of other compounds.

• Amphibians are sometimes called "indicators." They are called indicators because they are very sensitive to change in their environment.
• They breathe through their skin and breathe toxic and non-toxic components with it too.
• Nearly 33% of the amphibian species of the world are categorized as threatened on the Red List.
• Amphibians are dependent for their survival on a plentiful supply of fresh water that is free of chemical contaminants and harmful microbes.

• Thermal power is the "largest" source of power in India.
• About 65% of the electricity consumed in India is generated by thermal power plants, 22% by hydroelectric power plants, 3% by nuclear power plants and rest by 10% from other alternate sources.

• HIV: Human Immunodeficiency Virus.
• HIV causes AIDS and interferes with the body's ability to fight infections.
• The virus can be transmitted through contact with infected blood, semen or vaginal fluids. It destroys Lymphocytes.

• Carboxyhaemoglobin or carboxyhaemoglobin (symbol COHb or HbCO) is a complex of carbon monoxide and haemoglobin (Hb) that forms in red blood cells upon contact with carbon monoxide.
• Carbon Monoxide inhibits body stability to distribute O₂.
• Haemoglobin has a higher affinity for CO.
• Haemoglobin that binds CO becomes 'poisoned' and can no longer bind oxygen, destroying its function.

• The term allotrope refers to one or more forms of a chemical element that occurs in the same physical state. The different forms arise from the different ways, atoms may be bonded together. 
• There are many allotropes of carbon. These include diamond, graphite, graphene, carbon nanotubes, fullerenes, and carbon nanobuds.

• In the production of white paper, the wood pulp is bleached to remove any colour from the trace amounts of lignin that was not extracted in the chemical pulping process.
• There are three predominant methods of bleaching: Elemental chlorine bleaching, Elemental chlorine-free bleaching, and Totally chlorine-free bleaching.

• Dolomite is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg (CO₃)₂. The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite
• Dolomite is being used as Fillers by detergents, steel, paints, and ceramics.
• It provides valuable nutrients to plants and helps change the pH of the soil by raising it to match the plant’s needs.

• Fluorine deficiency is a disorder which may cause tooth decay also called tooth caries.
• Tooth decay is the breakdown of dental tissues by the acidic products released by the bacterial fermentation of dietary carbohydrates.
• Prevention of dental caries includes regular cleaning of the teeth, a diet low in sugar, and small amounts of fluoride.
• Fluoride treatment can help recalcification of tooth enamel.

• One of the causes of groundwater pollution is the use of fertilizers and pesticides.
• Only a fraction of the nitrogen-based fertilizers is converted to produce and other plant matter. The remainder accumulates in the soil or lost as run-off.
• High application rates of nitrogen-containing fertilizers combined with the high water-solubility of nitrate lead to increased runoff into surface water as well as leaching into groundwater, thereby causing groundwater pollution.
• The heavy use of nitrogenous fertilizers in cropping systems is the largest contributor to anthropogenic nitrogen in groundwater worldwide.

• Sodium bicarbonate is a white solid that is crystalline.
• Potassium bicarbonate is the inorganic white coloured compound.
• Caesium bicarbonate is a chemical compound. It can be used for synthesizing caesium salts.
• A compound, LiHCO₃, formed by the reaction of carbon dioxide with aqueous lithium carbonate and is known only in solution.

2011 Census was the 15^th Indian Census was conducted in two phases, house listing, and population enumeration.

• An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves
• The epicentre is the point on the Earth's surface directly above a hypocentre or focus, the point where an earthquake originates
• A hypocentre is the point of origin of an earthquake
• The intensity of the earthquake decreases with distance from the epicentre.
• Earthquakes largely occur along the converging plate boundaries.

• Madhya Pradesh has the largest Tribal population. It has more than 1.6 crore Schedule Tribe population who are 21% of state population according to 2011 census.
• The largest population in Madhya Pradesh is that of the Bhil tribe.
• The second highest tribal population is that of Odisha.
• The population of Mizoram in 2001 Census has been 888,573. Of them, 839,310 are Scheduled Tribes (STs) constituting 94.5 percent of the total population of the state.
• As per the Scheduled Tribes, Census of India 2001, Mizoram has 839,310 Scheduled Tribes (STs) constituting 94.5 percent of the total population of the state at that time.
• Nagaland is the highest percentage of the tribal population out of the total population of the state after Mizoram.

• The spring constant is the force applied if the displacement in the spring is unity.
• Hooke's law is a law of physics that states that the force needed to extend or compress a spring by some distance x scales linearly with respect to that distance. That is, where k is a constant factor characteristic of the spring: its stiffness. K is a spring constant.
• The spring constant will depend on the stiffness of the spring material, the thickness of the wire from which the spring is wound and, the diameter of the turns of the coil, the number of turns per unit length and the overall length of the spring.

• Gamma decay, type of radioactivity in which some unstable atomic nuclei dissipate excess energy by a spontaneous electromagnetic process.
• As only energy is emitted during gamma decay, the number of protons and neutrons remains the same. Hence, neither the mass number nor the atomic number of the nucleus changes.

• A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit.
• Bipolar Junction Transistor constructed with three doped Semiconductor Regions (Base, Collector, and Emitter) separated by two p-n Junctions.
• Emitter, Collector, and the Base is the correct order of decreasing impurities.
• Doping is the intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical, optical and structural properties.

• The audible frequency range, roughly 20 Hz - 20 kHz for Humans. The human ear is most sensitive to sounds between 1000 and 5000 Hz.
• Routine investigation for hearing loss usually involves an audiogram which shows threshold levels relative to a normal.
• How our ears perceive sound can be more accurately described by the logarithm of the intensity rather than directly to the intensity. The sound intensity level β in decibels of a sound having an intensity I in watts per meter squared is defined to be β(dB) = 10 log₁₀(I/I₀).
• When two or more waves traverse the same medium, the displacement of any element of the medium is the algebraic sum of the displacements due to each wave.
• Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of propagation of the wave. Longitudinal waves can travel in all media- Solids, Liquids, and Gases.

• An enzyme is a biological catalyst that accelerates a chemical reaction without altering its equilibrium.
• Enzymes are proteins functioning as catalysts that speed up reactions by lowering the activation energy.
• It remains unchanged after the reaction.
• Each enzyme has a temperature that it works optimally in, which in humans is around 98.6 degrees Fahrenheit, 37 degrees Celsius - the normal body temperature for humans.

• Altitude Sickness is caused by rapid exposure to low amounts of oxygen at high elevation.
• Altitude sickness is a disorder caused by being at high altitude.
• Low level of haemoglobin suggests Anaemia.

• Oxidation number, also called Oxidation State, the total number of electrons that an atom either gains or lose in order to form a chemical bond with another atom.
• The oxidation state of hydrogen is +1 in its compounds, except for metal hydrides, such as NaH, LiH, etc., in which the oxidation state for H is -1. Hence, it has more than one oxidation number.

• The Standard hydrogen electrode is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials.
• Electrode Potential is the electromotive force of a cell built of two electrodes.
• The value of the standard electrode potential is zero.

Oxygen = 65%, Carbon = 18%, Hydrogen = 9.5%, Nitrogen = 3.2%, Calcium = 1.5%, Phosphorus = 1.2%