If it takes 5 minutes to fill a 15L bucket from a water tap of diameter 2√π cm then the Reynolds number for the flow is (density of water = 10³ kg/m³ and viscosity of water = 10⁻⁷ Pa.s) close to.

The velocity can be determined from
Q = Av. (i)
where Q is volume flow rate, A and V are area and velocity of tube.
Given V = 15L = 15 × 10⁻³ m³, A = πD²/4 = π(0.02√π)²/4 = 10⁻³ m²
V = Q/t
Q = Vt = 15 × 10⁻³/5 = 0.5 × 10⁻³ m³/s
Using Q in equation (i)
v = Q/A = 0.5 × 10⁻³/10⁻³ = 0.5 m/s
Reynolds number for flow in a tube is given as
Rn = vD/ν
where ν is kinematic viscosity of fluid.
Rn = vDμ/ρ
where μ is viscosity of fluid
Rn = 0.5 × 0.02√π × 10³/10⁻⁷
Rn = 5649
hence correct answer is option D