Question

(b) An altimeter is an aneroid barometer which makes use of the change in
atmospheric pressure with the change in height above the sea level (altitude).
(i) How does the atmospheric pressure change with increase in height above
the sea level?
(ii) is the change in the atmospheric pressure uniform in part (i) above?
(iii) What is the approximate value of atmospheric pressure at sea level in S.I. unit?​

Answer 1

Explanation:

(i) With increase in altitude, the height air column above us decreases, air is rarified.So with decrease in depth and density, atmospheric pressure decreases with increase In height.

(ii) No, the change in atmospheric pressure is not uniform, although the decrease in height is uniform but the density of air does not decrease with altitude uniformly. The decrease in density of air is rapid in the lower layers ( altitudes) but is slow in the upper layers of the atmosphere.

(iii) The approximate value of atmospheric pressure at sea level is :-

$1.013 \: \times \: {10}^{5} \: pascals \: or \: 1 \: atm$

Answer 2

(i) With increase in altitude, the height air column above us decreases, air is rarified.So with decrease in depth and density, atmospheric pressure decreases with increase In height.

(ii) No, the change in atmospheric pressure is not uniform, although the decrease in height is uniform but the density of air does not decrease with altitude uniformly. The decrease in density of air is rapid in the lower layers ( altitudes) but is slow in the upper layers of the atmosphere.

(iii) The approximate value of atmospheric pressure at sea level is :-

1 atm