Part III Applied Science

PN Junction Diode A PN-junction diode is formed when a p-type semiconductor is fused to an n-type semiconductor creating a potential barrier voltage across the diode junction The effect described in the previous tutorial is achieved without any external voltage being applied to the actual PN junction resulting in the junction being in a state of equilibrium.  However, if we were to make electrical connections at the ends of both the N-type and the P-type materials and then connect them to a battery source, an additional energy source now exists to overcome the potential barrier. The effect of adding this ... Read more

Solar Energy : Source, Solar heating devices, solar cooker solar cell   Sunlight is Earth’s most abundant energy source and is delivered free of charge. Indeed, the energy from sunlight reaching the land surface of the earth  is thousands of times greater than the world’s current total annual consumption of energy. Yet harnessing sunlight’s energy content directly—rather than indirectly in fossil fuels, wind, or hydroelectric power—makes only a small contribution to humanity’s energy supply. Active solar techniques include the use of photovoltaic systems, concentrated solar power and solar water heating to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light-dispersing properties, ... Read more

Topological & Non-Topological Conservation   Conservation – shape and structure of networks of interacting organisms in ecological systems In-Situ Conservation   Protect whole ecosystem at all levels to protect threatened species (save entire forest to save tiger) Hot Spots – High endemism & high species richness (in India – Western Ghats (Agasthyamalai hills, Silent valley, Amambalam reserve) & Sri Lanka, Indo-Burma (NE India) – angiosperms, Sundalands (Nicobar Is.) & Himalaya – (dicot species) – cover less than 2% area with 44% species – if conserved extinction with decline by 30% 4 factors that determine hotspots Degree of endemism Degree of ... Read more

  CREDA – Chhattisgarh State Renewable Energy Development Agency   CREDA – Chhattisgarh State Renewable Energy Development Agency, has been constituted on 25th May 2001 under the Department of Energy, Government of Chhattisgarh for implementation of various schemes pertaining to Renewable Energy sources and Energy Conservation activities. It is registered under Society Act 1973 with the controlling body being Energy Department, Govt. of Chhattisgarh. CREDA is established as the State Nodal Agency by State Govt. for development and promotion of non-conventional & renewable sources of energy. Most of the scheme like National Programme on Bio-gas Development, Solar Thermal, Solar Photo ... Read more

Electric current Ohm’s law and Resistance   Electrical current is the flow of charged particles. The flow of charges will be constant in current electricity. Electric current flows from higher electric potential to lower electric potential. For the current to flow, it requires a circuit which is closed loop of a conducting material. The circuit consists of wires which are connected end to end and the electrons flow in same direction. A circuit has conductors (wire), switch, load and a power source. The circuit starts and stops at the same point. Usually copper wires are used as conductors without insulation. ... Read more

Some Important Organic Compounds   The chemical compounds of living things are known as organic compounds because of their association with organisms and because they are carbon-containing compounds. Organic compounds, which are the compounds associated with life processes, are the subject matter of organic chemistry. Among the numerous types of organic compounds, four major categories are found in all living things: carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates, lipids, proteins, and nucleic acids.       CARBOHYDRATES Almost all organisms use carbohydrates as sources of energy. In addition, some carbohydrates serve as structural materials. Carbohydrates are molecules composed of carbon, hydrogen, and oxygen; the ... Read more

Working principle and use of generator   Generator is a machine that converts mechanical energy into electrical energy. It works based on principle of faraday law of electromagnetic induction. The faradays law states that whenever a conductor is placed in a varying magnetic field, EMF is induced and this induced EMF is equal to the rate of change of flux linkages. This EMF can be generated when there is either relative space or relative time variation between the conductor and magnetic field. An electric conductor moves through a magnetic field, the magnetism will interface with the electrons in the conductor ... Read more

Magnetism Magnetism is one aspect of the combined electromagnetic force. It refers to physical phenomena arising from the force caused by magnets, objects that produce fields that attract or repel other objects. All materials experience magnetism, some more strongly than others. Permanent magnets, made from materials such as iron, experience the strongest effects, known as ferromagnetism. With rare exception, this is the only form of magnetism strong enough to be felt by people. Opposites attract Magnetic fields are generated by rotating electric charges, according to HyperPhysics. Electrons all have a property of angular momentum, or spin. Most electrons tend to ... Read more

precautions observed in electric experiments and Chemical effects of electric current When it comes to working with electrical equipment, putting safety precautions in place for any electrical project is always a top priority. From basic knowledge and equipment safety to personal precautions and equipment performance, knowing what to do to help prevent injuries and ensure safety can be a lifesaver. Avoid Water  A critical precaution when working with electrical equipment is staying out of water. If you’re working in an area where there is a good chance you’ll be around it, wear rubber boots at all times, but avoid standing ... Read more

Magnetic storm A magnetic storm is a period of rapid magnetic field variation. It can last from hours to days.  Magnetic storms have two basic causes: The Sun sometimes emits a strong surge of solar wind called a coronal mass ejection. This gust of solar wind disturbs the outer part of the Earth’s magnetic field, which undergoes a complex oscillation. This generates associated electric currents in the near-Earth space environment, which in turn generates additional magnetic-field variations — all of which constitute a “magnetic storm.” Occasionally, the Sun’s magnetic field directly links with that of the Earth. This direct magnetic ... Read more