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When air pressure increases the mercury in a barometer?

The height of the mercury column is about 76 cm (30 in) tall. As the pressure increases, it forces mercury higher up into the tube. When the air pressure falls, the level in the tube falls as well.

When air pressure decreases the mercury in a barometer blank?

Terms in this set (20)

Suppose the height of a column in a mercury barometer is decreasing. What is happening? When air pressure increases, the mercury in the tube rises. When air pressure decreases, so does the height of the mercury column.

What happens to mercury in a mercurial barometer when the air pressure increases?

With an increased weight of air above the reservoir, the mercury level rises to a higher level. If the weight of mercury is more than the atmospheric pressure, the mercury level falls (low pressure).

What happens when there is a decrease in air pressure?

As the pressure decreases, the amount of oxygen available to breathe also decreases. At very high altitudes, atmospheric pressure and available oxygen get so low that people can become sick and even die. … When a low-pressure system moves into an area, it usually leads to cloudiness, wind, and precipitation.

What happens to mercury in a barometer?

Mercury in barometric measurement is equivalent to the column of mercury in the barometer with the atmospheric pressure. Hence,as pressure increases it is obvious for increase of the mercury column as the column of mercury has the pressure dependency on its length above horizon.

How does pressure affect mercury?

Atmospheric Pressure and Altitude

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.

Why is the fluid in a barometer mercury?

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. … This is because mercury is 13.6 times more dense than water.

How is air pressure affected?

The number of air molecules above a surface determines air pressure. As the number of molecules increases, they exert more pressure on a surface, and the total atmospheric pressure increases. By contrast, if the number of molecules decreases, so too does the air pressure.

What causes atmospheric pressure?

Atmospheric pressure is caused by the gravitational attraction of the planet on the atmospheric gases above the surface and is a function of the mass of the planet, the radius of the surface, and the amount and composition of the gases and their vertical distribution in the atmosphere.

Did the mercury level increases or decreases?

The level of mercury in the glass trough increases or decreases with the change in atmospheric pressure. Thus a permanent scale cannot be marked on the glass tube is an advantage of a barometer.

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 in the tube if the atmospheric pressure decreases?

Since the space above the mercury in the tube contains a vacuum, the height of the mercury is directly proportional to atmospheric pressure. Therefore, if the atmospheric pressure decreases, the height of the mercury in the tube will decrease.

What happens when barometric pressure rises?

In general, a rising barometer means improving weather. In general, a falling barometer means worsening weather. When atmospheric pressure drops suddenly, this usually indicates that a storm is on its way.

What happens when air pressure increases?

For example, if air pressure increases, the temperature must increase. If air pressure decreases, the temperature decreases. It also explains why air gets colder at higher altitudes, where pressure is lower.

What causes low barometric pressure?

Areas of high and low pressure are caused by ascending and descending air. As air warms it ascends, leading to low pressure at the surface. As air cools it descends, leading to high pressure at the surface.

How does a mercury barometer measure pressure?

A mercury barometer is an instrument used to measure atmospheric pressure in a certain location and has a vertical glass tube closed at the top sitting in an open mercury-filled basin at the bottom. Mercury in the tube adjusts until the weight of it balances the atmospheric force exerted on the reservoir.

How do you find the pressure of mercury?

The density of mercury = 13.6 g/cm3. The hydrostatic pressure is given by p = hρg, with h = 760 mm, ρ = 13.6 g/cm3, and g = 9.81 m/s2.

How is atmospheric pressure measured with the help of a mercury barometer?

A simple barometer consists of a long glass tube (closed at one end, open at the other) filled with mercury and turned upside down into a container of mercury. … As air pressure decreases, more of the mercury drains from the tube. So the level of mercury in the tube provides a precise measure of air pressure.

What is air pressure write two effects of air pressure?

Answer:Atmospheric pressure is a large component of how weather works. As air moves around the globe, pockets of high pressure and low pressure build up. The areas of high pressure will rush into areas of low pressure, causing winds as the air moves.

What is a mercury barometer?

mercury barometer

Noun. tool that determines atmospheric pressure by measuring how much mercury moves in a glass tube.

What would happen to the column of mercury in the barometer if the atmospheric pressure fell?

Q. Explain what would happen to the column of mercury in the barometer as shown if the atmospheric pressure fell. As the pressure falls, the column of mercury will drop lower. … As the pressure falls, the column of mercury will rise higher.

How does the vapor pressure of mercury affect the pressure reading of the manometer?

When mercury is used as a liquid for manometer, the vapor pressure of water at 20 °C (2.33kPa) will produce 17.5mm of height difference. Procedure for measuring the saturated vapor pressure of a pure liquid at a specific temperature.

Why is mercury used as a liquid in a mercury barometer state three reason?

Barometer is used to measure air pressure and the pressure tendency can forecast short term changes in the weather. Again, mercury is also the only metal which is in liquid state at room temperature. It has a high coefficient of expansion and hence we can also use it as thermometric fluid.

What does the sudden fall in mercury in a barometer indicate?

Sudden fall in Mercury level: It signifies that there has been a fast fall in atmospheric pressure over the region. This will pool air from the surrounding regions vigorously and there is a possibility of storm in that area.

How does low and high pressure affect the weather?

High air pressure produces clear sky, dry and stable weather. In a low pressure zone, wind is circulated inwards and upwards rapidly. As a result, air rises and cools; clouds and precipitate are formed. Low air pressure produces unstable weather conditions like rain or storms.

How barometric pressure affects the body?

Barometric pressure is the weight of the atmosphere that surrounds us. Barometric pressure often drops before bad weather. Lower air pressure pushes less against the body, allowing tissues to expand. Expanded tissues can put pressure on joints and cause pain.

How does air pressure work?

The air around you has weight, and it presses against everything it touches. That pressure is called atmospheric pressure, or air pressure. It is the force exerted on a surface by the air above it as gravity pulls it to Earth. … Atmospheric pressure drops as altitude increases.

What causes air pressure to increase or decrease?

Air Pressure Basics

It increases as air density increases and lowers as air density lowers. It increases as temperatures increase and lowers as temperatures cool. It increases at lower altitudes and decreases at higher altitudes. Air moves from high pressure to low pressure.

Why does pressure decrease with altitude?

At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels. … Since most of the atmosphere’s molecules are held close to the earth’s surface by the force of gravity, air pressure decreases rapidly at first, then more slowly at higher levels.

What is the value of atmospheric pressure at sea level in mercury?

14.70 pounds per square inch

Standard sea-level pressure, by definition, equals 760 mm (29.92 inches) of mercury, 14.70 pounds per square inch, 1,013.25 × 103 dynes per square centimetre, 1,013.25 millibars, one standard atmosphere, or 101.325 kilopascals.

Mercury Barometer Problems, Physics – Air Pressure, Height & Density Calculations – Fluid Statics

The history of the barometer (and how it works) – Asaf Bar-Yosef

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