Effects of Atmospheric Pressure


 
 
Concept Explanation
 

Effects of Atmospheric Pressure

EFFECTS OF ATMOSPHERIC PRESSURE:

Atmospheric pressure is defined as the pressure exerted on an object by the weight of the air above it. The atmospheric pressure on the Earth's surface at sea level is about one hundred thousand pascal, i.e., 100 kPa. If such an enormous amount of pressure is acting on us, why do we not feel it? This is because the pressure of the blood in our blood vessels and that of the other fluids present in the body balances out the atmospheric pressure. Atmospheric pressure is measured using an instrument called barometer.

If the pressure of atmosphere is changed suddenly, the blood vessels in our body will burst due to the pressure of the blood and other fluids inside. This is why astronauts have to wear special pressurized suits- there is no air and , therefore, no air pressre in space.

Effects of the atmospheric pressure : 

1. Atmospheric movements : Vertical movements of air are air currents. The ultimate cause of these air movements is the pressure differences caused due to unequal distribution of the heat of the sun.

2. Clouds and fog : Fogs and clouds consists of condensed water vapours as particles small enough to remain in suspension. Clouds are formed mainly by adiabatic cooling of rising air. Air expands as it rises and such expension without addition of heat lowers the temperature leading to clouds formation. Clouds are also formed to a limited extend due to mixing of air currents.

3. Rainfall : The source of all precipitation is clouds. Cooling of moisture bearing air explains al precipitations.

Sample Questions
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Question : 1

If the pressure of atmosphere is changed suddenly, the blood vessels in our body will _____________ due to the pressure of the blood and other fluids inside.

Right Option : A
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Question : 2

If an enormous amount of pressure is acting on us, we do not feel it, this is because the pressure of the blood in our blood vessels and that of the other fluids present in the body _______________the atmospheric pressure.

Right Option : A
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Question : 3

Which of the following are correct :

(a) Fogs and clouds consists of condensed water vapours as particles small enough to remain in suspension.

(b) The cause of the vertical air movements is the pressure differences caused due to unequal distribution of the heat of the sun.

(c) Clouds are formed mainly by adiabatic cooling of rising air.

Right Option : D
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