The rate of flow of liquid in a tube of radius $r$ and length $l$,whose ends are maintained at a pressure difference $P$,is given by $V = \frac{\pi Q P r^4}{\eta l}$,where $\eta$ is the coefficient of viscosity. What is the value of $Q$?

Water from a pipe is coming at a rate of $100\, L/min$. If the radius of the pipe is $5\, cm$, the Reynolds number for the flow is of the order of: (density of water $= 1000\, kg/m^3$, coefficient of viscosity of water $= 1\, mPa\, s$)

In Poiseuille's method for the determination of the coefficient of viscosity,the physical quantity that requires the greatest accuracy in measurement is:

Two capillary tubes of the same length but different radii $r_1$ and $r_2$ are fitted in parallel to the bottom of a vessel. The pressure head is $P$. What should be the radius of a single tube that can replace the two tubes so that the rate of flow is the same as before?

The volume of a liquid is proportional to......,given its density $\rho$,viscosity $\eta$ and $t$ the time of flow through a capillary tube of length $L$ and radius $R$,with a pressure difference $p$ across its ends.

Two capillaries of same length and radii in the ratio $1:2$ are connected in series. $A$ liquid flows through them in a streamlined condition. If the pressure across the two extreme ends of the combination is $1 \ m$ of water,the pressure difference across the first capillary is...... $m$.