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प्रश्न
Ice cream appears colder to the mouth than water at 0℃. Give reason.
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उत्तर
This is because 1 g of ice at 0°C takes 336 J of heat energy from the mouth to melt at 0°C. Thus, mouth loses an additional 336 J of heat energy for 1 g of ice at 0°C than for 1g of water at 0°C. Therefore, cooling produced by 1 g of ice at 0°C is more than for 1g of water at 0°C.
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संबंधित प्रश्न
A solid metal weighing 150 g melts at its melting point of 800 °C by providing heat at the rate of 100 W. The time taken for it to completely melt at the same temperature is 4 min. What is the specific latent heat of fusion of the metal?
The temperature of 170 g of water at 50°C is lowered to 5°C by adding a certain amount of ice to it. Find the mass of ice added.
Given: Specific heat capacity of water = 4200 J kg-1 °C-1 and specific latent heat of ice = 336000 J kg-1.
Write the expression for the heat energy Q received by the substance when m kg of substance of specific heat capacity c Jkg-1 k-1 is heated through Δt° C.
Explain the term boiling point ?
Name the radiations for which the green house gases are transparent ?
Read the passage and answer the questions based on it.
If heat is exchanged between a hot and cold object, the temperature of the cold object goes on increasing due to gain of energy and the temperature of the hot object goes on decreasing due to loss of energy. The change in temperature continues till the temperatures of both objects attain the same value. In this process, the cold object gains heat energy and the hot object loses heat energy. If the system of both the objects is isolated from the environment by keeping it inside a heat-resistant box then no energy can flow from inside the box or come into the box. In this situation, we get the following principle.
Heat energy lost by the hot object = Heat energy gained by the cold object. This is called the ‘Principle of heat exchange’.
- Where does heat transfer take place?
- In such a situation which principle of heat do you perceive?
- How can this principle be explained in short?
- Which property of the substance is measured using this principle?
Numerical Problem.
How much heat energy is required to change 2 kg of ice at 0°C into water at 20°C? (Specific latent heat of fusion of water = 3,34,000 J/kg, Specific heat capacity of water = 4200 JKg–1K–1).
Derive Meyer’s relation for an ideal gas.
Two cylinders of equal height and radius are made of copper and aluminum. Which of them conducts heat faster?
