Question

As we go higher and higher atmospheric pressure __________________?
A) Increases
B) Decreases
C) Remains same
D) None of these

Answer 1

Hint: The density of air at higher temperature decreases. The water on mountains boils at a temperature less than the normal boiling point of water i.e. \[100^\circ \]C. When we climb up a mountain, we feel the problem in breathing.

Complete solution:
As we know due to the gravitational pull of the earth the gas molecules present in the air are also attracted towards earth. Due to this, the air near the earth's surface becomes denser and as we move away from the earth's surface the density of the air keeps on decreasing.
Now as we know that the density can be defined as mass per unit area. We are saying that the density of air is more near the earth's surface thus its mass will be more near-earth surface and mass will also keep on decreasing as we move away from the surface.
Now, as we know that weight is defined as the product of mass and acceleration due to gravity
$i.e.,W = m \times g$
This will be the force by which an object with mass will be attracted towards the earth
Now, as we have discussed earlier the mass of air is more near-earth surface so its weight will also be more near-surface this surface will experience more pressure
On the other hand, the mass of air decreases as we go up the surface so the weight will be less so lesser pressure will be experienced
So, from the above discussion it is clear that as we move away from the earth surface the density of air decreases thus, we experience a decrease in pressure

As we go higher, and higher atmospheric pressure decreases

Note: While we climb up a mountain, we feel shortness of breath because the density of air is low so less oxygen goes in when we breathe which is not sufficient for the body. Blood starts coming out of nose and ear when we climb up a mountain this is also because the external atmospheric pressure becomes lesser than our internal body pressure