As shown in the figure, a liquid is at the same level in both arms of a $U$-tube of uniform cross-section when at rest. If the $U$-tube moves with an acceleration '$f$' towards the right, the difference between the liquid heights in the two arms of the $U$-tube will be (acceleration due to gravity $= g$):

In a turbulent flow,the velocity of the liquid molecules in contact with the walls of the tube is

Fill in the blanks:
$(i)$ The surface tension of water at critical temperature is ......
$(ii)$ Bernoulli's equation is based on the conservation of ......
$(iii)$ The energy would be ...... if $1$ large drop of water splits into $8$ small drops of water.
$(iv)$ When strong wind passes over a building,the force acting on the building is in the ......

$A$ piece of metal weighs $46 \, g$ in air. When it is immersed in a liquid of specific gravity $1.24$ at $27^{\circ}C$,it weighs $30 \, g$. When the temperature of the liquid is raised to $42^{\circ}C$,the metal piece weighs $30.5 \, g$ and the specific gravity of the liquid at $42^{\circ}C$ is $1.20$. Calculate the coefficient of linear expansion of the metal.

During constant temperature, we feel colder on a day when the relative humidity is ....... $\%$

$A$ liquid flows through a horizontal tube. The velocities of the liquid in the two sections,which have areas of cross-section $A_1$ and $A_2$,are $v_1$ and $v_2$ respectively. The difference in the levels of the liquid in the two vertical tubes is $h$.