The area of cross-section of the wider tube shown in the figure is $800 \ cm^2$. If a mass of $12 \ kg$ is placed on the massless piston,the difference in heights $h$ in the level of water in the two tubes is ........ $cm$.

Name two devices working on Pascal's law.

$A$ hydraulic automobile lift is designed to lift cars with a maximum mass of $3000 \; kg$. The area of cross-section of the piston carrying the load is $425 \; cm^{2}$. What maximum pressure would the smaller piston have to bear?

$A$ hydraulic lift is shown in the figure. The movable pistons $A, B$ and $C$ have radii of $10 \,cm, 100 \,cm$ and $5 \,cm$ respectively. If a body of mass $2 \,kg$ is placed on piston $A$, what are the maximum masses that can be lifted by pistons $B$ and $C$ respectively?

Air is blown through a hole on a closed pipe containing liquid. Then the pressure will

In a hydraulic lift,the surface area of the input piston is $6 \ cm^2$ and that of the output piston is $1500 \ cm^2$. If $100 \ N$ force is applied to the input piston to raise the output piston by $20 \ cm$,then the work done is . . . . . . $kJ$.