JAM Classes

  Soil Profile The vertical and sequential arrangement of soil layers superimposed one above the other from the top surface to the unaffected rock below is termed as soil profile. The individual layers constituting the soil profile are called soil horizons. For instance, if we cut a vertical section of soil at a particular place, we clearly see different soil layers or horizons from top mature soil to the rock below. These horizons are formed through the differential downward movement of various materials such as organic matter, clay particles etc. moreover soil horizons vary in properties like colour, texture, structure, thickness, chemical composition, mineral content, consistency and reaction. In general soil profiles tend to become thicker, deeper and more altered over time. Soil profile can be as little as 10cm thick in immature soils and as deep as several meters in tropical areas. Soil profile is considered as one of the most important key factor for understandin...

  Composition of Soil Soil According to Soil Science Society of America, soil is defined as the unconsolidated mineral or organic matter on the immediate surface of the earth that serve as a natural medium for the growth of land plants. Composition of soil As far as the composition of the soil is concerned it is composed of four basic components: Minerals-           45% Organic matter 5% Water-               20-30 % Air-                   20-30% The amount of these components of the soil depends on the quality of vegetation, soil compaction and water present in the soil. But in reality the composition is very much complex and is dynamic in nature. The above four components are categorized under two headings solid phase and non-solid phase. Solid phase includes mi...

  Wastewater Treatment The water that has been used in various activities is termed as wastewater. It must be treated before its discharge into the environment. There are several stages of wastewater treatment. Wastewater treatment plants use primary, secondary and tertiary stages. 1.Primary treatment In this step waste water treatment primary treatment involves a number of physical process these include Screening In this process bar screens with 10 millimeters mesh size are used to block the flow of large floating debris like plastic cans, wrappers, wood pieces etc. so that they don’t enter into the next unit as these large debris may hinder the function of machinery to a great extent. Comminution In this process a comminutor is used to grind the debris that pass through the bar screen later on these grinded residue is removed by sedimentation. Grit removal In this physical process a large narrow tank is used to slow down the flow of incoming wastewater so th...

  Marine Pollution The change in the physical chemical and biological properties of sea water upon the addition of toxic pollutants from a variety of source either intentionally or unintentionally which can have a devastating impact particularly on marine biodiversity is referred to as marine pollution. According to UN the introduction by man directly or indirectly of substances or energy to the marine environment resulting in deleterious effects such as: hazard to human health, hindrance to marine activities impairment of the quality of seawater for various uses and reduction of amenities. Types of marine pollution The circle of marine pollution is quite vast which encompass many types of pollution which have an adverse effect on marine ecosystem. these are: Chemicals Light Noise plastic pollution Sources of marine pollution 1. Domestic Sewage The sewage disposal into rivers lakes etc. ultimately reach the marine ecosystem it contains a variety of pathoge...

    Previous Year Question Papers of Jammu and Kashmir State Board of School Education ENVIRONMENTAL SCIENCE CLASS:  12th            Year  2018   Time: 3 Hours                Maximum Marks: 70                       Long Answer Type   Questions                                                   (5   Marks Each) 1. Define air pollution . Describe any four sources of air pollution. Or  Describe very briefly any five measures taken by Govt. of India in controlling air     pollution 2. Write a detailed note on survivorship curves. Or Define population dynamics. Explain any four factors which affect population and its growth. 3. Define ecosystem stability and write a deta...