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प्रश्न
Describe an experiment to demonstrate that water absorbs heat during boiling at a constant temperature.
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उत्तर
BOILING POINT OF WATER AT CONSTANT TEMPERATURE:
Take some water in a beaker. Suspend and clamp a thermometer in a beaker in water so that the bulb of thermometer remains in water without touching bottom and sides of the beaker. Supply heat by the burner and note the temperature at room temperature (20°C nearly)
Record the temperature after every minute. The temperature rises and as it reaches 100°C water starts boiling. Though heat is being supplied temperature does not rise i.e. it remains constant at 100°C and bubbles formed are seen. Thus, the boiling point of water is 100°C and at boiling point heat supplied is absorbed by water at a constant temperature. Because this heat is being used to change every molecule of water into vapours.
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संबंधित प्रश्न
The temperature at which a liquid gets converted into its vapour state is called its
Boiling takes place from the
A certain quantity of water is heated from 20°C to 100°C. Its temperature is recorded after each 1 minute. The observations are:
| Time (in minute) | Temperature (in °C) |
| 0 | 20 |
| 1 | 30 |
| 2 | 40 |
| 3 | 50 |
| 4 | 60 |
| 5 | 70 |
| 6 | 80 |
| 7 | 90 |
| 8 | 100 |
| 9 | 100 |
| 10 | 100 |
| 11 | 100 |
| 12 | 100 |
Boiling of egg results in ______ change.
Water into steam on heating is called freezing.
Choose the correct statement of the following
Evaporation of a liquid at room temperature leads to a ____________ effect.
____________ is the change of solid state directly to vapour state without going through the ____________ state.
Alka was making tea in a kettle. Suddenly she felt intense heat from the puff of steam gushing out of the spout of the kettle. She wondered whether the temperature of the steam was higher than that of the water boiling in the kettle. Comment.
Why does the temperature of a substance remain constant during its melting point or boiling point?
