Three layers of liquid are flowing over a fixed solid surface as shown below. The correct order of velocity of the liquid in these layers is:

Which one of the following equations represents the variation of viscosity coefficient $(\eta)$ with temperature $(T)$?

The total pressure of a gas and a few drops of water in a container is $830 \, mm$. If the temperature of the container is decreased by $1 \%$,the new pressure is $............ \, mm$. The water vapor pressures at the two temperatures are $30 \, mm$ and $25 \, mm$ respectively.

At $300 \ K$ and $760 \ torr$ pressure,the density of a mixture of $He$ and $O_2$ gases is $0.543 \ g \ L^{-1}$. The mass percent of oxygen is approximately $(R = 0.0821 \ L \ atm \ K^{-1} \ mol^{-1})$

Assertion : Wet air is heavier than dry air.
Reason : The density of dry air is more than density of water.

The combination of plots which do not represent isothermal expansion of an ideal gas is