Consider two identical tanks with a bottom hole of diameter $d$. One tank is filled with water and the other tank is filled with engine oil. The height of the fluid column $h$ is same in both the cases. The fluid exit velocity in the two tanks are $V_1$ and $V_2$. Neglecting all losses, which one of the following options is correct?

In a laboratory experiment using a scaled down model to measure scour at a bridge pier, the Froude number is important. The ratio of the prototype length to the model length is 100 . If the velocity of the model is $1 \mathrm{~m} \mathrm{~s}^{-1}$, the velocity (in $\mathrm{m} \mathrm{s}^{-1}$ ) of the prototype is

For a fully-developed pipe flow, which of the following options is/are correct?

A pitot tube connected to a U-tube mercury manometer measures the speed of air flowing in the wind tunnel as shown in the figure below. The density of air is $1.23 \mathrm{~kg} \mathrm{~m}^{-3}$ while the density of water is $1000 \mathrm{~kg} \mathrm{~m}^{-3}$. For the manometer reading of $h=30 \mathrm{~mm}$ of mercury, the speed of air in the wind tunnel is __________ $\mathrm{m} \mathrm{s}^{-1}$ (rounded off to 1 decimal place).

Assume: Specific gravity of mercury $=13.6$

Acceleration due to gravity $=10 \mathrm{~m} \mathrm{~s}^{-2}$