Question

Which of the following statement is correct about atmospheric pressure?

• A. It is less at sea level than at the top of a mountain.
• B. It is caused due to weight of air molecules.
• C. It is exerted only above our head.
  
• D. It does not help us in breathing.
  

Answer 1

The correct option is B It is caused due to weight of air molecules.

Atmospheric pressure at a point is the pressure exerted due to the weight of the air molecules. Therefore, it is highest at sea level and less at the top of a mountain.
Pressure is always exerted in all directions at any point. So, atmospheric pressure is exerted in all directions wherever air is present. This is the reason we need no extra effort to inhale air and hence, atmospheric pressure helps in breathing.