Applying a pressure drop across a capillary results in a volumetric flow rate 'Q' under laminar flow conditions. The flow rate for the same pressure drop, in a capillary of the same length but half the radius is

According to Hagen Posuille equation for laminar flow
∆P=32 ulv/d^2. gc

Then , v= ∆P. d^2. gc/32ul...............(1)
We know that the volumetric flow rate given as Q= A.v..........(2)
area for capillary can be given as π/4 d^2

Put the value of v in eqn (2 )
Q= ∆P . d^4.gc/32ul
Q= (d/2)^4
We know that half the radius then ,,,, Q= (r/2)^4
Q= r^4/16
Q=

??