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Matter In Our Surroundings
What kind of energy transformation takes place in the following devices:
(i) Electric heater,
(ii) electric motor,
(iii) dynamo,
(iv) microphone,
(v) headphone,
(vi) hydro-electric power station,
(vii) steam engine,
(viii) solar battery,
(ix) photoelectric cell,
(x) electric cell.
(i) Electric heater: Electrical energy into heat.
(ii) Electric motor: Electrical energy into mechanical energy.
(iii) Dynamo: Mechanical energy into electrical energy.
(iv) Microphone: Sound into electrical energy.
(v) Headphone: Electrical energy into sound.
(vi) Hydroelectric power station: Mechanical energy into electrical energy.
(vii) Steam engine: Heat into mechanical energy.
(viii) Solar battery: Solar energy into electrical energy.
(ix) Photoelectric cell: Light into electrical energy.
(x) Electric cell: Chemical energy into electrical energy.
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What is the physical state of water at
100 °C
For any substance, why does the temperature remain constant during the change of state ?
Suggest a method to liquify atmospheric gases.
Convert the following temperatures to Kelvin scale.
35°C
Give reason for the following observations.
Naphthalene balls disappear with time without leaving any solid.
Give reason for the following observations.
We can get the smell of perfume sitting several metres away.
What is the physical state of water at
a) 25°C
b)00C
c)1000C
What is the physical state of water at
0°C
What is the physical state of water at
100°C
Give two reasons to justify
Water at room temperature is a liquid.
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