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प्रश्न
उत्तर
Farmers fill their fields with water on a cold winter night to protect the crops from frost. In the absence of water, if on a cold night the temperature of the surroundings falls below 0°C, then the veins of the plants will freeze. Due to the anomalous expansion of water, ice will occupy more volume than water. As a result of this expansion, veins shall burst and crops will be destroyed. But water sprinkled on the crops shall not allow the temperature of the veins to fall below 0°C.
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संबंधित प्रश्न
You have a choice of three metals A, B, and C, of specific heat capacities 900 Jkg-1 °C-1, 380 Jkg-1 °C-1 and 460 Jkg-1 °C-1 respectively, to make a calorimeter. Which material will you select? Justify your answer.
Water in lakes and ponds do not freeze at once in cold countries. Give a reason is support of your answer.
A refrigerator converts 100 g of water at 20°C to ice at -10°C in 35 minutes. Calculate the average rate of heat extraction in terms of watts.
Given: Specific heat capacity of ice = 2.1 J g-1°C-1
Specific heat capacity of water = 4.2 J g-1°C-1
Specific latent heat of fusion of ice = 336 J g-1
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Some heat is provided to a body to raise its temperature by 25°C. What will be the corresponding rise in temperature of the body as shown on the Kelvin scale?
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Specific latent heat of fusion of ice = 336 J/g)
Derive an expression for finding out the specific heat capacity of a body (solid) from the readings of an experiment given below:
(i) Mass of empty calorimeter (with stirrer) = m1 gm
(ii) Mass of the metal piece = M gm
(iii) Mass of colorimeter and water = m2 gm
(iv) Initial temperature and water = t1°C
(v) Temperature of hot solid (metal piece) = t2 °C
(vi) Final temperature of the mixture = t°C
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