The correct answer is Mercury has high density and low vapour pressure. Mercury is used in barometers and not water. This is because the high density of mercury gives a reasonable height of the column to measure atmospheric pressure. This is because mercury is 13.6 times denser than water.
Why is water not used as a barometric liquid?
Water is not a suitable barometric liquid because: (i) The vapour pressure of water is high, so its vapours in the vacuum space will make the reading inaccurate. (ii) Water sticks with the glass tube and wets it, so the reading becomes inaccurate.
Why is mercury used as a barometric liquid Give two reasons?
Two advantages of using mercury as barometric liquid: (i) The density of mercury is greater than that of all the liquids, so only 0.76m height of mercury column is needed to balance the normal atmospheric pressure. (ii) The mercury neither wets nor sticks to the glass tube therefore it gives the correct reading.
What is the fluid in a barometer?
Though other liquids can be used in a barometer, mercury is the most common. Its density allows the vertical column of the barometer to be of manageable size. If water were used, for instance, the column would have to be 34 feet high.
Why do we use mercury in thermometers?
Mercury is the only one in liquid state at room temperature. It’s used in thermometers because it has high coefficient of expansion. It also has a high boiling point which makes it very suitable to measure higher temperatures.
Can water be used as a barometric liquid?
Water is not used as a barometric liquid because.
Why mercury is used as barometric liquid give three reasons?
Complete answer: Mercury has many advantages when used as a measuring liquid in a barometer tube. Mercury has high density. Mercury is also a good conductor of heat. So, if the temperature of the system changes, mercury can come to that temperature more quickly.
Can we use alcohol as a barometric liquid give reason?
In the barometer case the operating premise is that the atmospheric pressure must be compared to the vacuum pressure of the mercury column. The reason is that alcohol, unlike mercury, has a large vapor presure near room temperature.
Could we use water instead of mercury to make a barometer?
Mercury is commonly used in barometers because its high density means the height of the column can be a reasonable size to measure atmospheric pressure. A barometer using water, for instance, would need to be 13.6 times taller than a mercury barometer to obtain the same pressure difference.
Why is mercury used as a barometer instead of water?
In barometer mercury is preferred over water because mercury has high density and low vapour pressure. mercury is shining and its level can be seen easily. What do we mean by atmospheric pressure what causes this pressure? Atmospheric Pressure is the force per unit area exerted on a surface due to the weight of air molecules above it.
How tall does a barometer have to be to use water?
A barometer using water, for instance, would need to be 13.6 times taller than a mercury barometer to obtain the same pressure difference. Click to see full answer. Also asked, why is water not used as a barometric liquid?
Why is vapour pressure important in a barometer?
The vapour pressure of liquid is significant in barometer,pump-piping system from an elementary point of view and the formation of cavitations in zones where pressure falls below vapour pressure.
Why does Mercury have a lower freezing point than water?
Mercury has high density and low length is essential for pressure measuring. Its high density helps to make small manometers. It does not evaporate like water would, and its lower freezing point means it will not freeze up at 0 deg C. Simply it has compactness, visibility and stability.
