What is the height of mercury column in a simple barometer at the sea level?

What is the height of mercury column in a simple barometer at the sea level?

At sea level and at a temperature of 0° Celsius (C), the height of the mercury column is approximately 30 inches, or 76 centimeters. This represents a pressure of approximately 14.7 psia. The 30-inch column is used as a reference standard.

How is the mercury column supported in a barometer?

A standard mercury barometer to measure atmospheric pressure is a tube with one end sealed. Again, if there is a difference in pressure between the two ends of the tube, a column of fluid can be supported in the tube, with the height of the column being proportional to the pressure difference.

Why does the height of the mercury column change from day to day?

Torricelli predicted that the height of the mercury column would change from day to day as the pressure of the atmosphere changed. Repeated experiments showed that the average pressure of the atmosphere at sea level is equal to the pressure of a column of mercury 760 mm tall.

What happens to the height of the mercury in the barometer tube?

The height of mercury above the bowl in a barometer is a measure of the pressure of air pushing on the mercury in the bowl. The mass of the mercury above the bowl times the force of gravity is equal to the pressure of air on the bowl. In (A) the tube is wider so the height has to be lower.

What is the height of mercury column in a barometer?

Measuring Atmospheric Pressure A pressure of 1 atm will support a column of mercury 76 cm high.

Why mercury is used in a barometer?

Mercury is employed in the barometer because its density is sufficiently high for a relative short column to be obtained. and also because it has very small vapour pressure at normal temperature. High density scales down the pressure head(h) to repesent same magnitude of pressure in a tube of smaller height.

Why mercury is used in barometer give reason?

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 does the height of mercury in a barometer decreases on going up on high mountain?

As the atmospheric pressure rises or falls so the mercury level in the tube rises or falls. If the atmospheric pressure drops it will not be able to hold up so much mercury and so the level in the barometer tube will fall. Up a mountain the air pressure is low and so the barometer reading will go down.

What happens to the height of the mercury column in a mercury barometer?

At sea level, a mercury column will rise a distance of 760 mm. This atmospheric pressure is reported as 760 mmHg (millimeters of mercury). At higher altitudes, the atmospheric pressure is decreased and so the column of mercury will not rise as high.

What happens when mercury barometer is tilted?

the vertical height of the mercury column decreases. When a mercury barometer is tilted, then the vertical height remains constant but length of mercury column increases.

How does the height of mercury affect the barometer?

Some of the most important factors that affects the height of Mercury in the Barometer are: 1. Altitude: The density of air and the atmosphere above becomes less with height. Since pressure depends on weight, the atmospheric pressure also decreases with height. Therefore, the reading in the barometer tube falls as it is taken up in the atmosphere.

Which is true of pressure due to mercury column?

Hence, Pressure due to mercury column = Pressure due to atmospheric pressure Pressure due to mercury column = Pressure due to atmospheric pressure The vertical height of the mercury column gives the required atmospheric pressure.

How is the pressure on a barometer related to the atmosphere?

The space at the top of the barometer tube is a vacuum and exerts no pressure on the mercury column. The atmosphere pushes against the mercury bath, which in turn pushes the mercury up the tube. Hence, Pressure due to mercury column = Pressure due to atmospheric pressure Pressure due to mercury column = Pressure due to atmospheric pressure

How to calculate the length of the mercury column?

The vertical height of the mercury column gives the required atmospheric pressure. ,where h is the height of mercury column, ρ ρ is density of mercury, g is gravitational acceleration. We can compute the length of the mercury column if 1 atm ( 1.013×105 Pa 1.013 × 10 5 Pa) of atmospheric pressure is acting on the mercury bath.