A spherical black body radiates 1000 watt power at 800 K. If the radius were halved and the temperature doubled, the power radiated (in watt) would be
Anonymous Quiz
21%
4500
42%
4000
29%
2000
8%
2250
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Statement-I: Heat given to an ideal gas under isothermal conditions is used completely to do external work.
Statement-II: The change in internal energy in a thermo dynamic process is independent of the path.
Statement-II: The change in internal energy in a thermo dynamic process is independent of the path.
Anonymous Quiz
40%
Statement 1 is true and Statement 2 is true
34%
Statement 1 is true and Statement 2 is false
20%
Statement 1 is false and Statement 2 is true
7%
Statement 1 is false and Statement 2 is true
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A transistor has
Anonymous Quiz
54%
Two p-n junctions
26%
One p-n junction
16%
Three p-n junctions
4%
Four p-n junctions
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The current carries in a PNP transistor is
Anonymous Quiz
36%
Free electrons
32%
Acceptor ions
14%
Donor ions
17%
Holes
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The base-emitter junctions of a transistor is
Anonymous Quiz
26%
a wide depletion layer
47%
Low resistance
22%
a reverse bias
5%
None
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👍19
Which is true for the entropy of a spontaneous reaction?
Anonymous Quiz
30%
ΔS(system) – ΔS(surroundings) > 0
50%
ΔS(system) + ΔS(surroundings) > 0
14%
ΔS(surroundings) > 0 only
6%
ΔS(system) > 0 only
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✍️Notes on Environmental Chemistry:
🔹Components of Environment:
➖Atmosphere: This comprises a blanket of gaseous layer around earth.
➖Hydrosphere: This comprises about 96% of earth’s surface & includes all sources of water like oceans rivers lakes, glaciers, ground water etc.
➖Lithosphere: It refers to earth’s solid crust containing the outer mineral cover. It comprises soil, minerals, organic matter etc.
➖ Biosphere: It refers to the domain of living organism in covalent with atmosphere hydrosphere as well as lithosphere.
🔹Environmental Pollution :
Process of contamination of the environment with harmful wastes arising mainly from human activities.
➖Pollutant: Any substance or species produced either by a natural source or by human activity, which produces adverse effect on the environment.
➖Contaminant: A substance which does not occurs in nature but is introduced by human activity into the atmosphere affecting its composition.
➖Source: The site from which the pollution or contaminants originate.
➖Sink: The material or medium which consumes or interacts with a long lived pollutant is called sink.
➖Receptor : Anything that is affected by the pollutants.
➖Threshold limit value (TLV) : This indicates the permissible limit of a pollutant in atmosphere to which a healthy worker is exposed during hours a day or 40 hours a week for life time without any adverse effects. TLV are determined by experimentation on animals, by use of medical knowledge, epidemiology surveys & environmental studies.
🔹Tropospheric pollution or Air pollution:
It is the atmosphere condition in which the presence of certain concentration produce harmful effects on man and his environment. These substances include:
(i) Gases such as oxides of sulphur, CO, oxide of N2 and hydrocarbons
(ii) Particulate matter such as dust, smoke, fumes etc.
(iii) Radioactive material & many others.
➖Primary pollutants : These are the pollutants which are emitted directly from the sources. Some examples are:
➖Particulate Matter : Such as ash, smoke, dust, fumes etc.
➖Inorganic gases : Such as sulphur dioxide, carbon monoxide etc.
🔹Particulate matter:
➖Soot: produced by incomplete combustion of carbonaceous fossils fuels such as coal, fuel oil, natural gas, wood etc in insufficient supply of oxygen.
➖Metal particles: These are released by various metal finishing operation. The micro particles of toxic metal & SO2 gas present in the polluted atmosphere get absorbed on the particles rendering them highly toxic.
➖Metal oxides : They are generated by combustion of fuels containing metallic compounds.
➖Lead salts: Their source is lead tetraethyl (Pb(C2H5)4) which is added to gasoline to improve its antiknock property. In order to avoid deposition of PbO suitable amounts of C2H4Cl2 & C2H4Br2 are added to gasoline along with Pb(C2H5)4.
➖Fly ash: It originates from the combustion of high ash fossil. It contains partially burnt particles of the fuels.
➖Asbestos dust: It originates from industrial units manufacturing asbestos sheets, gaskets ropes etc. Asbestos flowing & asbestos insulations also contribute towards asbestos dust in the atmosphere.
➖Solid Hydrocarbons: These are emitted from petroleum refineries & comprise of paraffins, olefins & aromatics.
➖Dust Particulates: Originate from natural, domestic, industrial or agricultural sources. These are thrown into atmosphere by volcanic eruptions, blowing of dust by wind, mining operations etc.
➖Acid mist : Sulphuric acid mist is produced when SO3 present in the atmosphere comes in contact with moisture. Nitric acid mist is produced when oxides of nitrogen, viz, NO & NO2, undergo the series of reactions in the atmosphere.
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🔹Components of Environment:
➖Atmosphere: This comprises a blanket of gaseous layer around earth.
➖Hydrosphere: This comprises about 96% of earth’s surface & includes all sources of water like oceans rivers lakes, glaciers, ground water etc.
➖Lithosphere: It refers to earth’s solid crust containing the outer mineral cover. It comprises soil, minerals, organic matter etc.
➖ Biosphere: It refers to the domain of living organism in covalent with atmosphere hydrosphere as well as lithosphere.
🔹Environmental Pollution :
Process of contamination of the environment with harmful wastes arising mainly from human activities.
➖Pollutant: Any substance or species produced either by a natural source or by human activity, which produces adverse effect on the environment.
➖Contaminant: A substance which does not occurs in nature but is introduced by human activity into the atmosphere affecting its composition.
➖Source: The site from which the pollution or contaminants originate.
➖Sink: The material or medium which consumes or interacts with a long lived pollutant is called sink.
➖Receptor : Anything that is affected by the pollutants.
➖Threshold limit value (TLV) : This indicates the permissible limit of a pollutant in atmosphere to which a healthy worker is exposed during hours a day or 40 hours a week for life time without any adverse effects. TLV are determined by experimentation on animals, by use of medical knowledge, epidemiology surveys & environmental studies.
🔹Tropospheric pollution or Air pollution:
It is the atmosphere condition in which the presence of certain concentration produce harmful effects on man and his environment. These substances include:
(i) Gases such as oxides of sulphur, CO, oxide of N2 and hydrocarbons
(ii) Particulate matter such as dust, smoke, fumes etc.
(iii) Radioactive material & many others.
➖Primary pollutants : These are the pollutants which are emitted directly from the sources. Some examples are:
➖Particulate Matter : Such as ash, smoke, dust, fumes etc.
➖Inorganic gases : Such as sulphur dioxide, carbon monoxide etc.
🔹Particulate matter:
➖Soot: produced by incomplete combustion of carbonaceous fossils fuels such as coal, fuel oil, natural gas, wood etc in insufficient supply of oxygen.
➖Metal particles: These are released by various metal finishing operation. The micro particles of toxic metal & SO2 gas present in the polluted atmosphere get absorbed on the particles rendering them highly toxic.
➖Metal oxides : They are generated by combustion of fuels containing metallic compounds.
➖Lead salts: Their source is lead tetraethyl (Pb(C2H5)4) which is added to gasoline to improve its antiknock property. In order to avoid deposition of PbO suitable amounts of C2H4Cl2 & C2H4Br2 are added to gasoline along with Pb(C2H5)4.
➖Fly ash: It originates from the combustion of high ash fossil. It contains partially burnt particles of the fuels.
➖Asbestos dust: It originates from industrial units manufacturing asbestos sheets, gaskets ropes etc. Asbestos flowing & asbestos insulations also contribute towards asbestos dust in the atmosphere.
➖Solid Hydrocarbons: These are emitted from petroleum refineries & comprise of paraffins, olefins & aromatics.
➖Dust Particulates: Originate from natural, domestic, industrial or agricultural sources. These are thrown into atmosphere by volcanic eruptions, blowing of dust by wind, mining operations etc.
➖Acid mist : Sulphuric acid mist is produced when SO3 present in the atmosphere comes in contact with moisture. Nitric acid mist is produced when oxides of nitrogen, viz, NO & NO2, undergo the series of reactions in the atmosphere.
🎖Click Here To Join Our Main Channel 🎖
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