Q.2.11. The blood pressure in humans is usually taken
using the arm. However, suppose the pressure reading were
taken on the calf of the leg of a standing person would there
be a difference?
Ans. Yes, blood pressure taken on the calf of the leg w
be higher than that taken from the arm. It is because the height
of the blood column is quite large at leg than that at the arm
Q.2.12. Why do fluids exert pressure on the walls of the
containing vessel ?
Answers
Answer:
Because of surface tension.
due to surgace tendion, it try to gain sphere shape so as to gain maximum area
The blood pressure measured at the calf would be larger than that measured at the arm. If we imagine the vascular system of the body to be a vessel containing a liquid (blood), the pressure in the liquid will increase with depth. The blood at the calf is deeper in the liquid than that at the arm and so it is is at higher pressure.
Blood pressures are normally taken at the arm because it is at approximately the same height as the heart. If blood pressures at the calf were used as a standard, adjustments would need to be made for the height of the person and the blood pressure would be different if the person were lying down.
Gases exert pressure on the walls of the containing vessel because the particles of gas have the maximum intermolecular space between them and also its kinetic energy is more that is the particles travel very fast and thus it exerts pressure on the walls of a container .
I hope you understand.