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30 Cards in this Set
- Front
- Back
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Define work |
W= Force x Distance(unit = Joules) |
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Work is a vector quantity (True/false) |
False. It is scalar |
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Is work done on a body where force is applied but it does not move |
No |
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When is the work done by a force 0 |
a) When S = 0 (no distance) b) When S is normal to the direction of force (90 degrees) |
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Define erg |
1 erg of work is done when force of 1 dyne displaces a body through a distance of 1 cm 1 J = 10^7 erg |
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Power is ____ |
rate of doing work (p= W/t) |
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Energy is |
the capacity of body to do work |
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Power and energy have same units (T/F) |
False |
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Formula for a) Potential energy b) kinetic energy |
a) W= mgh b) W = 1/2 mv^2 |
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State the work energy throrem |
Work done by a moving force on a moving body is equal to the increase in its kinetic energy |
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State two differences between potential and kinetic energy |
Potential - Energy possessed by a body due to its changed position. b) can only change to kinetic energy Kinetic - Energy possessed by body due to its motion b) can change to any other form |
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State 6 different types of energy and explain them |
Solar, heat, Wind, light, chemical, hydro, electrical, nuclear, geothermal, sound, magnetic, mechanical (any) |
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in a thermo couple _____ energy changes to ____ energy |
heat to electrical |
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in a battery _____ energy changes to ____ energy |
chemical to electrical |
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in a dynamo _____ energy changes to ____ energy |
electrical to mechanical |
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what are the characteristics of a source of energy ? |
a) Provide adequate amount of useful energy at a steady rate over a long period of time. b) Safe and convenient to use c) economical and easy to transport |
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What are the two types of energy sources. Give examples |
a) Renewable - wind /solar/hydro/biomass b) Non - renewable - petrol/coal |
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Natural gas is primarily made of |
methane |
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The process for separation of crude oil |
Fractional distillation |
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LPG stands for |
Liquefied Petroleum Gas |
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Steps for judicious use of energy |
a) use limited non - renewable sources. b) minimize wastage of energy. use on groups c) encourage and implement use of renewable energy sources. |
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Solar cells are made of semi conductors like________ |
silicon and gallium |
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define semiconductor |
Material that conducts less than metal but more than insulator |
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Explain the working of a nuclear power plant |
See Pg 52 Key points - Cadmium as control rods, controlled fission, excess heat absorbed by coolant , water in hear exchange gets heated, helps turn turbine to generate electricity. |
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Advantages and limitations of using nuclear power plants |
Adv - 1. small amount of fuel can generate tremendous amount of energy. 2. semi - automatic (until the fuel rods are depleted) Disadv - 1. not a clean source. 2. produces toxic waste products |
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State law of conservation of energy |
Energy is neither created or destroyed. only changes form. |
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Define Energy Degradation |
The gradual decrease of useful energy due to radiation. loss, friction. Give Examples |
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Law of conservation of mechanical energy |
Total Mechanical energy remains constant when kinetic and potential energy changes M (constant)= K + U |
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Adv and disadv of using solar panel |
Adv - 1. no maintenance required. 2. economical and easy to use in rural areas. 3. no pollution Diasdv - 1. high initial cost 2. low effeciency 3. produces dc not ac |
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Efficiency is ______ |
(Output Energy/Input Energy ) x 100 No units , its a % |
