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प्रश्न
Explain, why no tracks are left on the ice during ice skating?
उत्तर
The weight of the body acts on a very small area of skate, in comparison to that of ice. Under this high pressure, ice melts to form water below 0°C. The water so formed makes the surface water skating more slippery. But as soon as the skater moves further, the water does not experience any pressure and re-freezes into ice leaving no track on ice surface.
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संबंधित प्रश्न
State the effect of an increase of impurities on the melting point of ice.
What is the Greenhouse effect?
Explain the following:
The heat supplied to a substance during it change of state, does not cause any rise in its temperature.
Calculate the total amount of heat energy required to convert 100 g of ice at −10℃ completely into water at 100℃. Specific heat capacity of ice = 2.1 J g-1 K-1, specific heat capacity of water = 4.2 J g-1K-1, specific latent heat of ice = 336 J g-1.
Liquid ammonia is used in ice factory for making ice from water. If water at 20°C is to be converted into 2 kg ice at 0°C, how many grams of ammonia are to be evaporated? (Given: The latent heat of vaporization of ammonia = 341 cal/g)
A thermally insulated pot has 150 g ice at temperature 0°C. How much steam of 100°C has to be mixed to it, so that water of temperature 50°C will be obtained? (Given : latent heat of melting of ice = 80 cal/g, latent heat of vaporization of water = 540 cal/g, specific heat of water = 1 cal/g °C)
What do you mean by the statement?
'The specific latent heat capacity of fusion of ice is 336 J per g'?
Define the following terms:
(i) Latent heat,
(ii) Latent heat of fusion of ice.
Explain the meaning of the term latent heat. State its S. I. unit.
Why water get cooled in a ‘Surahi’ in hot season?
Explain the statement; “The specific latent heat of vaporization of wafer is 2260 × 103 J/kg”.
Why does evaporation causes cooling and why is water used in hot water bottles?
What observation you will record and how will you determine the specific latent heat of fusion of ice?
When ice is converted into water : constant temperature : : before the water evaporates : _______
Define boiling point of a liquid.
Write the name.
Products obtained when sugar is heated.
The latent heat of vaporisation is a term referred for the conversion of gas into liquid.
Specific latent heat L = ______.
Calculate the total amount of heat energy required to melt 200 g of ice at 0°C to water at 100°C. (Specific latent heat of ice = 336 Jg-1, specific heat capacity of water = 4.2 Jg-1 °C-1)
The diagram below shows a cooling curve for a substance:
- State the temperatures at which the substance condenses.
- The temperature range in which the substance is in liquid state.
- Why do we prefer ice to ice-cold water for cooling a drink?
