Choose the wrong statement when we measure the temperature of a wa | Filo

Class 7

Science

Physics

Heat

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150

Choose the wrong statement when we measure the temperature of a water kept in a beaker:

1. Thermometer should be kept vertical so that the bulb does not touch sides or bottom of the beaker
2. Thermometer should be kept vertical so that the bulb touches the bottom of the beaker
3. Thermometer should not be kept tilted so that the bulb touches sides or bottom of the beaker
4. Thermometer should be kept tilted without touching bottom or sides of the beaker
Solution: A pot of boiling water is actually slightly higher than the boiling point. The boiling point is defined as the temperature at which the vapour pressure is exactly equal to the external pressure. The “Normal Boiling Point” is the boiling point at exactly 1 atm of pressure. If you look closely at a pot of. Piling water you'll notice bubbles rising from the bottom of the pot. Those bubbles are pure water vapour and since they have pushed back the water that is on top of themselves and the air over the water, they must have had a pressure greater than the external pressure to do that. Those bubbles will stop expanding when the pressure just exactly equals the boiling point and will stay there as they finish rising in the pot. This, the steam just above the water will be a better measure of the boiling point because it will not yet have had a chance to cool down.

Hence Option A is correct
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