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प्रश्न
Give scientific reasons for the following:
It is much easier to skate on rough ice than on glass.
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
200 g of hot water at 80°C is added to 400 g of cold water at 10°C. Neglecting the heat taken by the container, calculate the final temperature of the mixture of water. Specific heat capacity of water = 4200 J kg-1K-1.
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Fill in the following blank using suitable word:
1 cal = .......... J
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(i) a change in its temperature?
(ii) a change in itsstate without any change in its temperature?
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(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.
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A Bunsen burner raises the temperature of 500g of water from 10°C to 100°C in 5 minutes. What heat is supplied per second?
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