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प्रश्न
Explain, why does a wise farmer water his fields, if forecast is forst?
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उत्तर
The frost can seriously damage the leaves and fruit of plants. When a farmer waters his fields, during, night, this water gives large amount of heat energy, because 1 g of water will liberate 4.2 J of energy for every 1°C fall in temperature. Thus, the air around the field is saturated with heat energy and its temperature does not fall below 0°C. Thus, no frost is formed.
संबंधित प्रश्न
50 g of metal piece at 27°C requires 2400 J of heat energy so as to attain a temperature of 327°C . Calculate the specific heat capacity of the metal.
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Solve the following problem.
Specific latent heat of vaporization of water is 2.26 × 106 J/kg. Calculate the energy needed to change 5.0 g of water into steam at 100 ºC.
Read this activity and answer the following questions.
- Take three spheres of iron, copper and lead. the lead of equal mass.
- Put all the three spheres in boiling water in the beaker for some time.
- Take the three spheres out of the water.
- All the spheres will be at a temperature 100 °C.
- Put them immediately on the thick slab of wax.
- Note, the depth that each of the sphere goes into the wax.
Questions:
- Which property is determined from this activity?
- Give name to that property.
- Explain the term principal of heat exchange with the help of this activity.
Conductors have generally high specific heat capacities and insulators have low specific heat capacities.
Which method is used to determine the specific heat capacity of both solids and liquids by mixing a substance of unknown specific heat with water?
