Target ESE 2022 (Basics of Material Science & Engineering)

 👉Atoms are made of electron, proton and neutrons. 

👉 Electrons and protons are negative and positive charged particles respectively. The magnitude of each charged particle in an atom is 1.6 x 10^-19 Coulombs.

👉The mass of electron is negligible as compare to proton and neutron.

👉The unit of mass is an atomic mass unit

          1 a.m.u = 1.66 x 10^-27 kg 

👉Matter is composed of tiny particles called atoms.

   1. Stable particles: Electron, proton and neutron

   2. Unstable particles- positron, neutrino, anti-neutrino and meson

   3. Composite particles- Deuteron and alpha- particles

👉Electron: It carries a very small negative electrical charge.

                      It has negligible mass i.e. its mass is 1/850th of the mass of hydrogen atom.

👉Proton: It carries small positive electrical charge. 

                   Mass of each proton is same as that of hydrogen atom.

                   Protons are also present in all all the atoms.

 👉Neutron: It does not carry any electrical charge. Its mass is equivalent to that of proton.

👉 Positron or positive electron: The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1 e

👉Meson: The mass of meson is in between the mass of electron and proton.

                   Mesons were discovered during cosmic ray studies.

👉 There are two types of meson (i) p-meson which is heavier (ii) m-meson which is light

👉Both type of mesons may be either negatively or positively charged.

👉Deuteron: It is positively charged.

                      It is heavy hydrogen nucleus.

 👉 Alpha Particles: They are double charged helium nucleus.

                                    They appear as product of radioactive decay.

👉Meson carries a either negative or positive charged.

👉The weight of an electron is 1/1836 of the weight of proton or neutron.

👉Avogadro Number(N) = 6.023 x 10^23

👉Mean distance between atoms in the range of 0.23 nm.

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Target ESE 2022 ( Basics of Energy and Environment)

👉 Ecology: Study of ecosystem. 

👉Ecosystem: It was coined by A.G Tansley

👉Environment: Everything that surrounds or affects an organism during its life time is collectively known as its environment. It comprises both living (biotic) and non-living (abiotic) components.

👉Components of Environment  

             Abiotic (Non-living)                                     Biotic (Living)

               Energy                                                          Green plants

              Radiation                                                      Non-green plants

          Temperature & heat flow                                 Decomposers

                Water                                                             Animals

                 Soil                                                                  Man

👉When an ecosystem is healthy (i.e. sustainable) it means that all the elements live in balance and are capable of reproducing themselves. Ecosystem can be as small as a single tree or as large as entire forest.

👉Types of ecosystem

        (i) Natural                        (ii) Artificial (e.g.  Zoo, aquarium, gardens)

👉 Natural ecosystem can be classified as

       (a) Terrestrial (e.g. Forests, Grasslands, deserts)      (b) Aquatic (e.g.  Lakes, Rivers, Oceans, Ponds)

👉Ecotone: Transition zone between two different zones of ecosystem.(Ecotone is a zone of junction between two or more diverse ecosystems)

e.g. Mangrove forests represent an ecotone between marine and terrestrial ecosystem

 

👉In the Ecotone region , population densities of certain species is greater than adjoining regions. This phenomenon is called Edge Effect.

e.g. Coastal region, wetlands

👉 Characteristics of Ecotone

• It may be very narrow or quite wide
• It has the conditions intermediate to the adjacent ecosystems. Hence it is a zone of tension
• It is linear
• A well developed ecotones contain some organisms which are entirely different from that of the adjoining communities. 

             

                          

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