Question

Q.5 Since the envelop of air around us is called atmosphere. The air in our atmosphere
extend
up to 300 km from the surface of the earth as the air has weight, so the whole
atmosphere contin a tremendous amount of weight which in turn exert pressure on the
surface of earth and this pressure is known as atmospheric pressure. Thus, atmospheric
pressure is due to the weight of nir present in the atmosphere. Atmospheric pressure also
acts in all the directions.
Pressure is force per unit area. So, if we imagine a unit aren and a very long cylinder
standing on it filled with air, then the weight of nir in this cylinder is called as atmospheric
pressure. On the surface of earth, the atmospheric pressure is maximum at sea level. It is
due to the reason that the column of air above the earth is largest at sea level and the
magnitude of atmospheric pressure at the sea level is 101.3 kilopascal which is equal to the
weight of 10 elephants for each 1m². So, as we go up from the surface of the Earth then the
atmospheric pressure goes on decreasing. It is because the weight of air above us goes on
decreasing therefore the atmospheric pressure at the top of high mountain is much less
than at its base.
Answer the following questions on the basis of above description:-
5.1 Name the device used to measure the atmospheric pressure.
5.2 Give the numerical value of atmospheric pressure at sea level.
5.3 As we go to higher altitude the atmospheric pressure goes on decreasing. Give the
reason.
5.4 Name the unit of pressure.​

Answer 1

Answer:

5.1) Barometer is the device used to measure the atmospheric pressure.

5.2) The standard atmosphere (symbol: atm) is a unit of pressure equal to 101325=1.01325×10⁵ Pascals

5.3) Air in the atmosphere is not the same at all levels. It is more dense near the earth. It goes on thinning out as we go up. So, there being more air near the earth, there is more air pressure. As the amount of air goes on decreasing, its weight and the air pressure goes on decreasing consequently.

5.4) The SI Unit of pressure is Pascals (Pa)

Hope this helps :)