Reynold's number of flow is given by where, v= velocity of flow, ρ= density of fluid, r= radius of tube and η= viscosity of flow Now, required ratio is
R1
R2
=
(
2v1ρr1
η
)
(
2v2ρr2
η
)
R1
R2
=
v1
v2
×
r1
r2
...(i) Now, by equation of continuity A1v1=A2v2 ⇒