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प्रश्न
Explain the meaning of the term latent heat. State its S. I. unit.
उत्तर
The heat absorbed or liberated by a substance during its change of state at a constant temperature is called latent heat. Its S. I. unit is J/kg.
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संबंधित प्रश्न
1 g ice of 0℃ melts to form 1 g water at 0℃. State whether the latent heat is absorbed or given out by ice.
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.
Explain the following temperature vs time graph.
What is meant by latent heat? How will the state of matter transform if latent heat is given off?
Water expands on reducing its temperature below ______°C.
Define specific latent heat of vaporization of a substance.
What happens to the heat supplied to a substance when the heat supplied causes no change in the temperature of the substance?
Explain, why no tracks are left on the ice during ice skating?
If there is no Heat loss to the surroundings, the heat released by the condensation of m1 g of steam at 100°C into water at 100°C can be used to convert m2 g of ice at 0°C into water at 0°C.
(i) Find:
(a) The heat lost by steam in terms of m1
(b) The heat gained by ice in terms of m2
(ii) Form a heat equation find the ratio of m2 : m1
Specific latent heat of vaporization of steam = 2268 kJ/kg
Specific latent heat of fusion of ice = 336 kJ/kg
Specific heat capacity of water = 4200 J/kg°C
Match the columns.
| Column A | Column B |
| 1) Absolute humidity | a) J or cal |
| 2) Latent heat | b) J/kg °C |
| 3) Specific heat capacity | c) kJ/kg |
| 4) Heat | d) no unit |
| e) kg/m3 |
During reheating, ice is converted to water at a temperature of 0 °C.
Write scientific reason.
The bottom of some steel utensils used for cooking is copper.
600 g of copper at 50°C is mixed with lOOOg water at 20°C. Find the final temperature of the mixture. The specific heat capacity of copper is 0.4 Jg-1°C-1 and that of water is 4.2 Jg-1°C-1
Calculate the amount of heat required to convert 200g of ice at 0°C into the water at 0°C Specific latent heat of fusion of ice = 336 Jg-1
Observe the following graph and answer the following questions:
- What does the graph represent?
- What does the line AB represent?
- What does the line BC represent?
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?
20 g of ice at 0°C absorbs 10,920 J of heat energy to melt and change to water at 50°C. Calculate the specific latent heat of fusion of ice. Specific heat capacity of water is 4200 J kg-1 K-1.
