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SCIENCE MCQS

SCIENCE MCQ SET-18

Q.5 Which group of algae can provide nitrogenous nutrients to paddy cultivation under natural field conditions ? A) Blue-Green Algae B) Brown Algae C) Green Algae D) Red Algae Ans. A   Q.6 Tissue culture technique can be used for : 1) developing virus free plants 2) Multiplication of elite genotypes of useful trees 3) production of secondary metabolites of plants Codes : A) 1 & 3 B) 2 & 3 C) 1 b& 2 D) 1,2,3 Ans. D   Q.7 What is the naturally occurring form of Vitamin D in the human skin ? A) 1, 25 dihydroxy cholecalciferol B)  25 hydroxy cholecalciferol C) 7 hydrocholesterol D) Calciferol Ans. D   Q.8 The chemical substance Taxol is said to have curative value for malignant tumours. It is obtained from : A) Shoots of taxodium sp. B) Roots & fruits of Taxodium sp. C) bark from stem of Taxus sp. D) roots of taxus sp. Ans. C   Q.9 Spirogyra is classified into which of the following class ? A) Algae B) Fungi C) Bacteria D) None of the above Ans. A   Q.10 Which among the following are present in Plant Cell but not in the Animal cell ? 1) Cell wall 2) Cell membrane 3) Plastids Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.11 Which among the following are the decomposers ? 1) Algae 2) Fungi 3) Bacteria Codes : A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. B    

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SCIENCE MCQ SET-17

Q.1 Energy park scheme initiated by the centre under the Special Area Demonstration Programme aims to : 1) create awareness about renewable energy systems and devices 2 ) setting up of state level education parks 3) demonstrate the use of NRSE technologies Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.2 Which of the following techniques are involved in Holography ? 1) LASER 2) Diffraction 3) Interference Codes: A) 1 & 2 B) 2 & 3 C) 1 & 3 D) 1,2,3 Ans. D   Q.3 Which of the following are the coolants that are employed in a nuclear reactor ? 1) Water 2) Carbon di oxide 3) Graphite Codes : A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. C   Q.4 Which among the following are considered as the bio-fuels ? 1) Curcas 2) Jatropha 3) Karanje Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.5 Which among the following are positively charged ? 1) Electrons 2) Protons 3) Neutrons Codes: A) 1 & 3 B) 2 & 3 C) Only 2 D) 1,2,3 Ans. C   Q.6 Which among the following are an example of chemical changes ? 1) Rusting of Iron 2) Boiling of water 3) Dissolving of sugar in water Codes: A) 1 & 3 B) Only 1 C) 2 & 3 D) Only 2 Ans. B   Q.7 Digestive processes of which one of the following constituents of food will be hampered if bile is not secreted by the gall bladder ? A) Fat                       B) Protein C) Carbohydrate       D) Vitamin Ans. A   Q.8 Which of the following radio isotopes are used in treatment of cancer ? 1) Iodine-131 2) Cobolt-60 3) Arsenic-74 Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. C   Arsenic-74 is used to detect tumour   Q.9 Which among the following can be classified as an insulator ? 1) Paper 2) Rubber 3) Plastics 4) Glass Codes : A) 1,3,4 B) 2,3,4 C) 1,2,3 D) 1,2,3,4 Ans. D   Q.10 With reference to the Indian Missile Programme, which among the following statements are correct ? 1) Akash is a surface to air missile with a range of 60 kilometers 2) Nag is a fire-and-forget anti-tank missile, with a 5-7 kilometer range Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C   Q.11 Which among the following is the strike range of Agni-I missile ? A) 700 – 800 km B) 600 – 700 km C) 500- 600 km D) 400 – 500 km Ans. A  

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SCIENCE MCQ SET-16

Q. Energy park scheme initiated by the centre under the Special Area Demonstration Programme aims to : 1) create awareness about renewable energy systems and devices 2 ) setting up of state level education parks 3) demonstrate the use of NRSE technologies Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q. Which of the following techniques are involved in Holography ? 1) LASER 2) Diffraction 3) Interference Codes: A) 1 & 2 B) 2 & 3 C) 1 & 3 D) 1,2,3 Ans. D   Q. Which of the following are the examples of coolant that are employed in a nuclear reactor ? 1) Water 2) Carbon di oxide 3) Graphite Codes : A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. C   Q. Which among the following are considered as the bio-fuels ? 1) Curcas 2) Jatropha 3) Karanje Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q. Which among the following are positively charged ? 1) Electrons 2) Protons 3) Neutrons Codes: A) 1 & 3 B) 2 & 3 C) Only 2 D) 1,2,3 Ans. C   Q. Which among the following are an example of chemical changes ? 1) Rusting of Iron 2) Boiling of water 3) Dissolving of sugar in water Codes: A) 1 & 3 B) Only 1 C) 2 & 3 D) Only 2 Ans. B Boiling of water & Dissolving of sugar in water are physical changes   Q. Which of the following radio isotopes are used in treatment of cancer ? 1) Iodine-131 2) Cobolt-60 3) Arsenic-74 Codes: A) 1 & 3 B) 2 & 3  C) 1 & 2 D) 1,2,3 Ans. C   Arsenic-74 is used to detect tumour Q. Which among the following can be classified as an insulator ? 1) Paper 2) Rubber 3) Plastics 4) Glass Codes : A) 1,3,4 B) 2,3,4 C) 1,2,3 D) 1,2,3,4 Ans. D   Q. With reference to the Indian Missile Programme, which among the following statements are correct ? 1) Akash is a surface to air missile with a range of 60 kilometers 2) Nag is a fire-and-forget anti-tank missile, with a 5-7 kilometer range Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C DRDO launched an ambitious programme named IGMDP for the development of 5 different missiles i.e., Prithvi, Agni, Trishul, Akash and Nag   Q. Which among the following is the strike range of Agni-I missile ? A) 700 – 800 km B) 600 – 700 km C) 500- 600 km D) 400 – 500 km Ans. A   Q. In Urban planning there is a term “Zoning”, what does it signifies ? 1) It decides the minimum requirements of space for present and future use of land 2) It prevents overcrowding and also check unhealthy land uses in the areas Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C          

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SCIENCE MCQ SET-15

Q.1 In most of the children’s toys, a toxic chemical remains present. In this respect, which among the following statements is/are correct?   1. The name of the toxic element is phthalates which are esters of phthalic acid.   2. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility and longevity.   3. They are easily released into environment because there is no covalent bond between the phthalates and plastics in which they are mixed.   Codes:   A) 1 only   B) 1 and 2 only   C) 2 and 3 only   D) 1, 2 and 3   Ans. D   Q.2 With reference to Earth Overshoot day, which among the following statements are correct ?   1) It is observed when humans created more waste than nature can absorb   2) Every year it is celebrated as World environment day   3) Humans consume more than biosphere can replace   Codes:   A) 1 & 3   B) 2 & 3   C) 1 & 2   D) 1,2,3   Ans. A   Q.3 With reference to pill camera which is a step further in endoscopy , consider the following statements :   1) Pill camera can take  12 images per second   2) Pill camera can be steered by doctors from outside the body through patient’s skin through magnetic device   Codes :   A) Only 1   B) Only 2   C) Both are correct   D) Both are incorrect   Ans. A   Q.4 Aflatoxin is produced as a result of growth of :   A) Algae   B) Fungus   C) Bacteria   D) Protozoan   Ans. B   Q.5 Lead chromate is used as an adulterant in :   A) Black pepper   B) Wheat flour   C) Turmeric powder   D) Chilli powder   Ans. C   Q.6 Which one of  the following is used in preparing Kargasok tea ?   A) Fungus   B) Bacterium   C) Insect larva   D) Latex of plant   Ans. A   Q.7 Which of the following is detected & estimated by the pollution check carried out on motor cars at service stations ? A) Lead & carbon particles B) Carbon di oxide C) Carbon monoxide D) Oxides of nitrogen & sulphur Ans. A   Q.8 In the vincinity of Iron ore mining areas which among the following elements would be high in ground water ? A) Calcium B) Nitrate C) Fluoride D) Arsenic Ans. D   Q.9 In context with the news there was term Pusa Hydrogel, which among the following statements are correct ? 1) It helps in surviving of plants by releasing water for plants 2) It helps in improving seed germination 3) It generally absorbs retain water Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.10 With reference to eco-cooker which among the following are correct ? 1) It can cook multiple times thus preserving food’s nutritional value 2) It is energy efficient & consumes less energy than LPG 3) Modified burner design & sealed close circuit are the characteristics of the eco-cooker Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D  

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SCIENCE MCQ SET-14

Q.1 Statements: 1) Soaps can lather well in hard & soft water 2) Synthetic detergents form soluble calcium & magnesium salts with hard water. 3) Hard water contains chloride & sulphate salts of Magnesium & Calcium Options: A) 1 & 2 B) Only 3 C) 1,2,3 D) 2 & 3 Ans. D   Q.2 statements: 1) sulphur dioxide & Nitrogen dioxide contribute to Acid Rain. 2) Oxides of carbon emitted from coal burns contribute to acid rain. Options: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. A   Q.3 Why the aqueous solution of copper sulphate is acidic in nature ? A) Because salt undergoes electrolysis B) Because salt undergoes Photolysis C) Because salt undergoes dialysis D) Because salt undergoes hydrolysis Ans. D   Q.4 Hard Water is not  suitable for : 1) drinking 2) Washing clothes 3) use in boilers 4) irrigating crops Codes: A) 1 & 4 B) 1 & 2 C) 2 & 3 D) 1,2,4 Ans. C   Q.5 consider the following statements: 1) Polluted water has high Biological Oxygen Demand. 2) Water pollution in river is measured by dissolved amount of Chlorine. Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. A  

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SCIENCE MCQ SET-13

Q.1 In context with the Arms Trade Treaty, which of the following statements are correct? 1) It is a legally binding weapon ban treaty 2) It covers all conventional arms 3) It aims to set global standards for regulation of trade & International transfers Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. B   Q.2 Consider the differences between Aplastic as well as Sickle cell Anaemia : 1) In Aplastic Anaemia bone marrow does not produce new cells to replace replenish blood cells while in Sickle cell Anaemia it is characterized by the sickle shape of blood cells 2) Aplastic is not genetic while Sickle cell anaemia is genetic Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C   Q.3 Which of the following diseases are included under the Expanded Programme On Immunisation ? 1) Diphtheria 2) Measles 3) Polio 4) Tuberculosis Codes: A) 1,3,4 B) 2,3,4 C) 1,2,3 D) 1,2,3,4 Ans. A   Q.4 In the year 2014 between which of the following countries exercise named as Sahayog – Kaijin” has taken place ? A) India & US B) US & Japan C) India & Japan D) India & Russia Ans. C   Q.5 Regarding IMF (International Monetary Fund) quota system, consider the following statements : 1) The major objective is to raise funds for the loans 2) IMF Quota is assigned to member country as well as non member country 3) IMF is working to facilitate International trade, promote employment, as well as for economic growth Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.6 In context with the Target Accelerator Programme , consider the following statements : 1) It has been designed for the improvement of retail Industry 2) It focuses in the area of mobile , data & analytics Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C   Q.7 Which of the following two countries has signed defence corporation deal ? A) India & US B) India & Saudi Arabia C) India & Myanmar D) India & Russia Ans. B   Q.8 Which of the following would be the economic impact of the Ukraine crisis on India ? 1) Rupee would weak against dollars 2) FDI inflow into India will be affected 3) It will increase Current Account deficit as India will have to spent more dollars to buy brent in case of increased oil & gas prices Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.9 In context with the LIBOR (London Interbank Offered Rate), consider the following statements: 1) It is the interest rate at which banks can borrow funds from other banks in LIBOR market 2) It is considered as long term interest rates Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. A  

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SCIENCE MCQ SET-12

Q.1 Which among the following are the sources of Mercury poisoning ? 1) Fluorescent lamps 2) Volcanoes 3) Waste disposal 4) Coal fired power plants Codes: A) 1 & 3 B) 1,3,4 C) 1,2,3,4 D) 3 & 4 Ans. C   Q.2 In context with the Gasification, which among the following are correct ? 1) The power derived from gasification and combustion of the gas is considered to be a source of renewable energy 2) It converts organic or fossil fuel based carbonaceous materials into carbon monoxide, hydrogen and carbon dioxide. 3) Gasification of fossil fuels is currently widely used on industrial scales to generate electricity Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.3 In context with the Cold chain , which among the following statements are correct ? 1) It is a temperature-controlled supply chain for the storage & distribution purpose 2) It ensures the shelf life of products such as fresh agricultural produce, seafood,etc. Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C   Q.4 Which of the following are the limitations in the use of hydrogen as a fuel ? 1) High storage vessel pressure 2) Low energy content 3) Filling of hydrogen in vehicles 4) Transportation & Storage Codes: A) 1,3,4 B) 2,3,4 C) 1,2,3 D) 1,2,3,4 Ans. D   Q.5 In context with the Nanomites, which among the following are correct ? 1) These are the nanosized particles for killing infected cells in body 2) These are biological as well as non-biological nano particles Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. A These are non-biological nano particles   Q.6 In context with the Bt Cotton, consider the following statements : 1) It is the only genetically modified crop approved in India 2) It is resistant for the growth of the pests Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. A Conditions are positive for the growth of the pests   Q. 7 Rainbow colours in the compact disk are due to which of the following factors ? 1) Diffraction 2) Interference 3) Reflection Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.8 Statements: 1) Arab league, EU, Vatican city & Red Cross have the observer status in the United nation 2) All the observers do not have voting rights 3) All the observers do not have a speaking rights in the UN General Assembly Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. C EU have a speaking rights in the UN General Assembly   Q.9 Statements: 1) Trans fats are considered beneficial for the human body 2) Double bond chemistry of the fat molecules  in Trans fats causes a Plaque formation 3) Omega-3 fatty acids are considered healthier than the saturated fatty acids Codes : A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. B Trans fats are considered dangerous for the human body      

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SCIENCE MCQ SET-10

Q.1 Consider the statements regarding Central Asian Nuclear Weapon Free Zone Treaty (CANWFZ) : 1) This treaty makes the region nuclear weapon free zone 2) It is a legally binding to not to use nuclear weapons against the party of the treaty 3) It forbidded the development & testing of nuclear weapons within the Central Asia Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D   Q.2 Recently Photon-Photon Collider experiment has been conducted to determine which of the following ? A) Conversion of light into matter B) Conversion of light into electron C) Conversion of light into positron D) Conversion of light into matter & electron Ans. A   Q.3 Why recently China has resurrect Silk Road Development Project ? 1) To improve maritime trade security by improving relations between South & South East Asia 2) To establish free trade zones connecting coastal areas of china with South east Asia Nations Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C   Q.4 Regarding CITES (Convention on International Trade In endangered Species), consider the following statements : 1) It is an international agreement between the government to ensure International trade of Plants & animals do not threaten their survival 2) It is a legally binding on all the parties of the convention Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C   Q.5 Which of the following are the differences between Exit Polls & Post Poll Survey ? 1) Exit Polls are done outside the polling station immediately after the casting of vote while Post Poll survey is done after the voting at the home of the voters 2) In Exit Polls Voters are caught immediately after exiting from the booths while Post Poll Survey is based on leisurely & detailed interactions Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C   Q.6 In which of the following Bio fuels have the role ? 1) Prevent deforestation & soil erosion 2) Preservation of bio diversity 3) Providing food security Codes: A) 1 & 3 B) 2 & 3 C) All are correct D) All are incorrect Ans. D A biofuel is a fuel that contains energy from geologically recent carbon fixation. These fuels are produced from living organisms. Examples of this carbon fixation occur in plants and microalgae. These fuels are made by a biomass conversion (biomass refers to recently living organisms, most often referring to plants or plant-derived materials). This biomass can be converted to convenient energy containing substances in three different ways: thermal conversion, chemical conversion, and biochemical conversion. This biomass conversion can result in fuel in solid, liquid, or gas form. This new biomass can be used for biofuels. Biofuels have increased in popularity because of rising oil prices and the need for energy security. Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn,sugarcane, or sweet sorghum. Cellulosic biomass, derived from non-food sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as agasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the USA and in Brazil. Current plant design does not provide for converting the lignin portion of plant raw materials to fuel components by fermentation. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel additive to reduce levels of particulates,carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe. In 2010, worldwide biofuel production reached 105 billion liters (28 billion gallons US), up 17% from 2009, and biofuels provided 2.7% of the world’s fuels for road transport, a contribution largely made up of ethanol and biodiesel .Global ethanol fuelproduction reached 86 billion liters (23 billion gallons US) in 2010, with the United States and Brazil as the world’s top producers, accounting together for 90% of global production. The world’s largest biodiesel producer is the European Union, accounting for 53% of all biodiesel production in 2010. As of 2011, mandates for blending biofuels exist in 31 countries at the national level and in 29 states or provinces. The International Energy Agency has a goal for biofuels to meet more than a quarter of world demand for transportation fuels by 2050 to reduce dependence on petroleum and coal. There are various social, economic, environmental and technical issues relating to biofuels production and use, which have been debated in the popular media and scientific journals. These include: the effect of moderating oil prices, the “food vs fuel” debate, poverty reduction potential, carbon emissions levels, sustainable biofuel production, deforestation and soil erosion, loss of biodiversity, and impact on water resources.   Q.7 In which of the following Shale gas is found ? 1) Assam 2) Gujarat 3) Gangetic Plain Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D Shale gas is natural gas that is found trapped within shale formations. Shale gas has become an increasingly important source of natural gas in the United States since the start of this century, and interest has spread to potential gas shales in the rest of the world. In 2000 shale gas provided only 1% of U.S. natural gas production; by 2010 it was over 20% and the U.S. government’s Energy Information Administration predicts that by 2035, 46% of the United States’ natural gas supply will come from shale gas.   Q.8 Statements: 1) Monazite & thorium are the source of the rare earth elements 2) India is dependent upon the neighbor country for the import of rare earth elements Codes: A) Only 1 B) Only

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SCIENCE MCQ SET-9

Q.1 Which among the following are the biopesticides ? 1) Bacteria 2) Virus 3) Fungi 4) Proteins Codes: A) 1 & 3 B) 1,3,4 C) 1,2,3 D) 1,2,3,4 Ans. D •  In the EU, biopesticides have been defined as “a form of pesticide based on micro-organisms or natural products”. •  the US EPA states that they “include naturally occurring substances that control pests (biochemical pesticides), microorganisms that control pests (microbial pesticides), and pesticidal substances produced by plants containing added genetic material (plant-incorporated protectants) or PIPs”.   Q.2 Which among the following methods are used for the water disinfection ? 1) Ozonation 2) Chloramine 3) UV radiation 4) Chlorination Codes: A) 1,3,4 B) 2,3,4 C) 1,2,3 D) 1,2,3,4 Ans. D   Q.3 Which among the following regarding Chlorination are correct ? 1)  It is a process used in other water sources to reduce the bacterial and algal residue in the water 2) Chlorine is highly disinfectant which kills the pathogens through the oxidation of the organic molecules 3) It acts by disintegrating the cell wall of the microorganisms Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D Water chlorination is the process of adding chlorine (Cl2) or hypochlorite to water as a method of water purification to make it fit for human consumption as drinking water. In particular, chlorination is used to prevent the spread of waterborne diseases.   Q.4 Which among the following statements regarding water purification technique are correct ? 1) In Situ Chemical Oxidation is the remediation technique used for soil and groundwater remediation to reduce the concentrations of environmental contaminants 2) UV radiation & ozone treatment leaves no residual disinfectant in the water Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C Additional treatment options 1. Water fluoridation: in many areas fluoride is added to water with the goal of preventing tooth decay. Fluoride is usually added after the disinfection process. In the U.S., fluoridation is usually accomplished by the addition of hexafluorosilicic acid, which decomposes in water, yielding fluoride ions. 2. Water conditioning: This is a method of reducing the effects of hard water. In water systems subject to heating hardness salts can be deposited as the decomposition of bicarbonate ions creates carbonate ions that precipitate out of solution. Water with high concentrations of hardness salts can be treated with soda ash (sodium carbonate) which precipitates out the excess salts, through the common-ion effect, producing calcium carbonate of very high purity. The precipitated calcium carbonate is traditionally sold to the manufacturers of toothpaste. Several other methods of industrial and residential water treatment are claimed (without general scientific acceptance) to include the use of magnetic and/or electrical fields reducing the effects of hard water. 3. Plumbosolvency reduction: In areas with naturally acidic waters of low conductivity (i.e. surface rainfall in upland mountains of igneous rocks), the water may be capable of dissolving lead from any lead pipes that it is carried in. The addition of small quantities of phosphate ion and increasing the pH slightly both assist in greatly reducing plumbo-solvency by creating insoluble lead salts on the inner surfaces of the pipes. 4. Radium Removal: Some groundwater sources contain radium, a radioactive chemical element. Typical sources include many groundwater sources north of the Illinois Riverin Illinois. Radium can be removed by ion exchange, or by water conditioning. The back flush or sludge that is produced is, however, a low-level radioactive waste. 5. Fluoride Removal: Although fluoride is added to water in many areas, some areas of the world have excessive levels of natural fluoride in the source water. Excessive levels can be toxic or cause undesirable cosmetic effects such as staining of teeth. Methods of reducing fluoride levels is through treatment with activated alumina and bone charfilter media. Other water purification techniques Other popular methods for purifying water, especially for local private supplies are listed below. In some countries some of these methods are also used for large scale municipal supplies. Particularly important are distillation (de-salination of seawater) and reverse osmosis. 1. Boiling: Bringing it to its boiling point at 100 °C (212 °F), is the oldest and most effective way since it eliminates most microbes causing intestine related diseases, but it cannot remove chemical toxins or impurities. For human health, complete sterilization of water is not required, since the heat resistant microbes are not intestine affecting. The traditional advice of boiling water for ten minutes is mainly for additional safety, since microbes start getting eliminated at temperatures greater than 60 °C (140 °F). Though the boiling point decreases with increasing altitude, it is not enough to affect the disinfecting process. In areas where the water is “hard” (that is, containing significant dissolved calcium salts), boiling decomposes the bicarbonate ions, resulting in partial precipitation as calcium carbonate. This is the “fur” that builds up on kettle elements, etc., in hard water areas. With the exception of calcium, boiling does not remove solutes of higher boiling point than water and in fact increases their concentration (due to some water being lost as vapour). Boiling does not leave a residual disinfectant in the water. Therefore, water that is boiled and then stored for any length of time may acquire new pathogens. 2. Granular Activated Carbon filtering: a form of activated carbon with a high surface area, adsorbs many compounds including many toxic compounds. Water passing through activated carbon is commonly used in municipal regions with organic contamination, taste or odors. Many household water filters and fish tanks use activated carbon filters to further purify the water. Household filters for drinking water sometimes contain silver as metallic silver nanoparticle. If water is held in the carbon block for longer period, microorganisms can grow inside which results in fouling and contamination. Silver nanoparticles are excellent anti-bacterial material and they can decompose toxic halo-organic compounds such as pesticides into non-toxic organic products. 3. Distillation involves boiling the water to produce water vapour. The vapour

SCIENCE MCQ SET-9 Read More »

SCIENCE MCQ SET-8

Q.1 Which of the following belongs to the Aves ? 1) Bat 2) Crow 3) Parrot 4) Eagle Codes: A) 2,3,4 B) 1,3,4 C) 1,2,3 D) 1,2,3,4 Ans. A   Q.2 Which of the following rays are used in CT Scan ? A) Visible light B) Infra red rays C) Ultrasonic waves D) X-rays Ans. C   Q.3 What name has been given to the ICBM developed by India with a range of more than 2000 km ? A) Trishul B) Prithvi C) Agni II D) Akash Ans. C   Q.4 Which of the following has the highest share in the power generation ? A) Nuclear power B) Hydro power C) Thermal power D) All of the above Ans. C   Q.5 In context with the news, what was nano humming bird ? A) New variety of honey bee B) New species of hitherto undiscovered humming bird C) Small electric car that can take 3600 turn D) An unmanned spy plane developed in U.S.A Ans. D   Q.6 Pink revolution is related to : A) Garlic B) Onion C) Grapes D) Cotton Ans. D   Q.7 Which of the following are correct ? 1) Mirage is an optical illusion arising due to Total Internal Reflection of light 2) Concave mirrors are used in search of lights 3) In summer white or light coloured clothes are preffered to dark coloured clothes 4) Convex mirror with a small aperture is used by the doctors to examine ear , nose & throat Codes: A) 1,3,4 B) 2,3,4 C) 1,2,3 D) 1,2,3,4 Ans. C   Q.8 In context with the Graphene which among the following statements are correct ? 1) It is an allotrope of carbon with single-layer transparent sheet 2) It has a low weight which makes it strong 100 times more than the steel 3) It has a two dimensional properties Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D Graphene is pure carbon in the form of a very thin, nearly transparent sheet, one atom thick. It is remarkably strong for its very low weight (100 times stronger than steel and it conducts heat and electricity with great efficiency. While scientists had theorized about graphene for decades, it was first produced in the lab in 2004.  Because it is virtually two-dimensional, it interacts oddly with light and with other materials. Researchers have identified the bipolar transistor effect, ballistic transport of charges and large quantum oscillations.   Q.9 In context with the Biofertiliser, which among the following are correct ? 1)  It contains living microorganisms that promotes growth by increasing the availability of primary nutrients 2) Bio-fertilizers add nutrients through the natural processes of nitrogen fixation 3)  The microorganisms in bio-fertilizers restore the soil’s natural nutrient cycle and build soil organic matter. 4) Bio-fertilizers do not contain any chemicals which are harmful to the living soil 5) They fulfil plant nutrient requirements by supplying the organic nutrients through microorganism and their byproducts Codes: A) 1,3,4,5 B) 2,3,4,5 C) 1,2,3,4 D) 1,2,3,4,5 Ans. D   Q.10 Which among the following statements are correct regarding Biopesticides : 1) Biopesticides  function in photosynthesis &  growth of plant physiology 2) Their biodegradable, economical and renewable alternatives enable them to use under the organic farming systems Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C      

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