Question

which phrase describes air pressure?

decreases with denser air
decreases as altitude decreases
equals mass divided by volume
decreases as a result of fewer air particles pushing down
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Answer 1

decreases with dense air

Answer 2

The correct phrase for air pressure is 4th option: decreases as a result of fewer air particles pushing down.

• Air pressure is a force that is exerted by the gaseous molecules in the atmosphere as well as other particles present in the atmosphere.
• When particles collide with each other it exerts pressure and is called air pressure.
• If there are more particles, more pressure will be created but with fewer air particles pushing down or colliding the pressure decreases.
• 1st option is wrong because it increases with denser air.
• 2nd option is incorrect because it decreases with an increase in altitude.

• 3rd option is wrong because mass by volume is density and not air pressure.
• Hence, 4th option is right.