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प्रश्न
उत्तर
Ice melts under pressure. So, when the steel blades of the skates pressed on the ice, the ice melts. The water formed makes the skates slide easily over the ice, reducing friction. So, when we are skating on ice, we are skating on a thin film of water, which acts like lubricating oil. Nothing such happens in case of glass.
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संबंधित प्रश्न
The amount of heat energy required to convert 1 kg of ice at – 10℃ to water at 100℃ is 7,77,000 J. Calculate the specific latent heat of ice. Specific heat capacity of ice = 2100 J kg-1K-1, Specific heat capacity of water = 4200 J kg-1 K-1.
The specific heat capacity of a substance A is 3,800 Jkg `"^(–1)K^(–1)` and that of a substance B is 400 `"^(–1)K^(–1)`. Which of the two substances is a good conductor of heat ? Give a reason for your answer.
40 g of ice at -16°C is dropped into water at 0°C, when 4 g of water freezes into ice. If specific heat capacity of ice is 2100 J/kg°C, what will be the latent heat of fusion of ice?
Fill in the following blank using suitable word:
Ice at o0C is colder than ...........at o0C.
Fill in the following blank using suitable word:
Evaporation causes ..........
A mass of 50 g of a certain metal at 150° C is immersed in 100 g of water at 11° C. The final temperature is 20° C. Calculate the specific heat capacity of the metal. Assume that the specific heat capacity of water is 4.2 J g-1 K-1.
Explain, why is water used as a coolent in motor car radiators?
A copper calorimeter of mass 50g contains 100g of water at 20°C. A metallic piece of mass 250 g is heated to 100°C and is then dropped into the calorimeter. The contents of the calorimeter are well stirred and its final highest temperature is recorded to be 28 °C. If the specific heat capacity of water is 4.2 J/g°C and of copper is 0.4 J/g°C, find:
(i) the heat gained by water,
(ii) the heat gained by calorimeter,
(iii) total heat supplied by the metal piece, and
(iv) the specific heat capacity of metal.
50 g of ice at 0°C is added to 300 g of a liquid at 30°C. What will be the final temperature of the mixture when all the ice has melted? The specific heat capacity of the liquid is 2.65 Jg-1 °C-1 while that of water is 4.2 J g-1 °C-1. Specific latent heat of fusion of ice = 336 Jg-1.
If you apply equal amount of heat to a solid, liquid, and gas individually, which of the following will have more expansion?
