Question

The atmospheric pressure is usually measured in the unit of :
A. newtons per square meter
B. pascal
C. cm of mercury
D. mm of mercury

Answer 1

The atmospheric pressure is usually measured in B. Pascal

Explanation:

• The Pascal is a SI derived unit. It is usually used in measurement of internal pressure, Young's modulus and stress.
• The value of standard atmosphere pressure is 101325 Pa which is used as reference pressure.
• According to recommendation of World Meteorological Organisation, the atmospheric pressure is given in hectopascal.
• There are multiple units in pascals such as millibar, kilopascal and hectopascal.
• $1 \mathrm{Pa}=1 \frac{\mathrm{N}}{\mathrm{m}^{2}}=1 \frac{\mathrm{kg}}{\mathrm{m} \mathrm{s}^{2}}=1 \frac{\mathrm{J}}{\mathrm{m}^{3}}$
• Where, N = Newton; kg = Kilogram; m = Meter; s = Second; J = Joule

Answer 2

B. pascal

Explanation:

Atmospheric pressure is the pressure exerted by the atmosphere, or rather the weight of air above a point on Earth. It can be measured using a barometer. The unit of pressure is Pascals. (pascal = Newton per square metre)

As we go to a higher altitude on Earth, the weight of air above it decreases, so the pressure will also be lesser. So atmospheric pressure decreases with increasing elevation.

Standard atmosphere (atm) is 101,325 Pa which is equivalent to the mean sea-level atmospheric pressure on Earth. Meaning the Earth's atmospheric pressure at sea level is approximately 1 atm.

Option B is the answer.