$A$ tube is bent into an $L$ shape and kept in a vertical plane. If these three liquids are kept in equilibrium by the piston of area $A$,the value of $\frac{F}{A}$ is:

$A$ triangular lamina of area $A$ and height $h$ is immersed in a liquid of density $\rho$ in a vertical plane with its base on the surface of the liquid. The thrust on the lamina is

$A$ $U$-tube having a horizontal arm of length $20 \ cm$ has a uniform cross-sectional area of $1 \ cm^2$. It is filled with water of volume $60 \ cc$. What volume of a liquid of density $4 \ g/cc$ should be poured from one side into the $U$-tube so that no water is left in the horizontal arm of the tube? (Answer in $cc$)

Three identical vessels are filled up to the same height with three different liquids $A, B$ and $C$ of densities $\rho_A, \rho_B$ and $\rho_C$ (where $\rho_A > \rho_B > \rho_C$). The pressure at the bottom of the vessels is:

Two vessels have the same base area but different shapes. The first vessel takes twice the volume of water that the second vessel requires to fill up to a particular common height. Is the force exerted by the water on the base of the vessel the same in the two cases? If so,why do the vessels filled with water to that same height give different readings on a weighing scale?

In Guericke's experiment to show the effect of atmospheric pressure,two copper hemispheres were tightly fitted to each other to form a hollow sphere and the air from the sphere was pumped out to create a vacuum inside. If the radius of each hemisphere is $R$ and the atmospheric pressure is $p$,then the minimum force required (when the two hemispheres are pulled apart by the same force) to separate the hemispheres is