Question

How atmospheric pressure decreases with increase in moisture:

• A. Due to air expansion
• B. Due to decrease in density
• C. Decrease in density of air
• D. None

Answer 1

Answer: (C)

Decrease in density of air

Atmospheric pressure decreases mainly due to
i) increase in temperature of air
ii)increase in moisture of air
In the first case,as the air expands due to heat,its density decreases,followed by decrease in pressure.in the second case,an increase in moisture in air results in the overall decrease in the density of the air and,hence ,pressure falls.