Physics · Pressure due to a fluid column, Pascal's law and its applications, effect of gravity on fluid pressure
A drop of alcohol is introduced into the vaccum space of mercury barometer compl
A drop of alcohol is introduced into the vaccum space of mercury barometer completely evaporates and then slightly lowers the height of the barometer. If the barometer tube is raised from this position, the height of the barometer will
- A. fall
- B. rise
- C. remains stationery
- D. falls first and then rises
Step-by-step solution
The alcohol vapor exerts a pressure on the mercury column, reducing its height compared to a vacuum. When the tube is raised, the volume above the mercury increases, causing the vapor pressure to decrease (assuming ideal gas behavior). Since the atmospheric pressure is constant, the reduced vapor pressure allows the mercury column to rise to a higher level, approaching the original barometric height.
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