Three different liquids are filled in U-tube as shown in figure. Their densities are ${\mathrm{\rho }}_1, {\mathrm{\rho }}_2 \mathrm{and} {\mathrm{\rho }}_3$ , decreasing, respectively. From the figure, we may conclude that

Using Bemoulli’s equation, we obtain

${\mathrm{\rho }}_1\mathrm{gh} + {\mathrm{\rho }}_3\mathrm{g}\frac{\mathrm{h}}{2} = {\mathrm{\rho }}_2\mathrm{gh}$

Figure shows an indicator diagram. During path 1-2-3, 100 cal is given to the system and 40 cal worth work is done. During path 1-4-3, the work done is 10 cal. Then