Name: Capillary Rise
Uploaded: 2019-07-19
Duration: 10 min 29 s
Description: Have you ever seen what happens to a celery stalk dipped in red-coloured water? We notice that after a day or two, the leaves turn reddish! Let's learn the r...

Question

State Pascal's law and verify it with the help of an experiment.

Accepted Answer

Pascal's law states that the pressure in a fluid at rest is the same at all points if they are at the same height.

Consider an element in the interior of fluids at rest as shown in the below figure. The element ABC-DEF is in the right form of a right angle triangle prism.

Figure: The proof of Pascal laws

The above figure shows an element in the interior of fluid at rest. The element ABC-DEF is in the form of a right-angled prism. The fluids exert pressure $P_{a}, P_{b} and P_{c}$ on the element of an area corresponding to the normal forces $F_{a}, F_{b}, F_{c}$ as shown in the above figure on the faces $B E F C, A D F C and A D E B$ denoted by $A_{a}, A_{b} and A_{c}$ respectively.

By equilibrium, $F_{b} \sin (θ_{2}) = F_{c}, F_{b} \cos (θ_{2}) = F_{a}$

By geometry, $A_{b} \sin (θ_{2}) = A_{c}, A_{b} \cos (θ_{2}) = A_{a}$

Thus, $\frac{F_{b}}{A_{b}} = \frac{F_{c}}{A_{c}} = \frac{F_{a}}{A_{a}}$

Hence, the pressure exerts the same in all directions in a fluid at rest.

State Pascal's law and verify it with the help of an experiment.

Important Questions on Mechanical Properties of Fluids

Learn and Prepare for any exam you want !