The instrument fitted in the carburetor of an automobile to provide the correct mixture of air and fuel necessary for combustion works on which of the following principles?

Does it matter if one uses gauge instead of absolute pressures in applying Bernoulli's equation? Explain.

$A$ manometer connected to a closed tap reads $3.5 \times 10^5 \ N/m^2$. When the valve is opened,the reading of the manometer falls to $3.0 \times 10^5 \ N/m^2$. The velocity of the flow of water is ........ $m/s$.

In a horizontal tube, the water pressure changes by $1500 \text{ N m}^{-2}$ between points $A$ and $B$ as shown in the figure below. The cross-sectional areas at $A$ and $B$ of the tube are $40 \text{ cm}^2$ and $20 \text{ cm}^2$, respectively. Find the rate of flow of water through the tube.

At what speed will the velocity head of a stream of water be equal to $40 \ cm$ of $Hg$ (in $cm/sec$)?

Different heads are in Column - $I$ and their formulas are given in Column - $II$. Match them appropriately.

Column - $I$	Column - $II$
$(a)$ Velocity head	$(i)$ $\frac{P}{\rho g}$
$(b)$ Pressure head	$(ii)$ $h$
$(c)$ Potential head	$(iii)$ $\frac{v^2}{2g}$