The terminal velocity of a small sphere settling in a viscous fluid varies as the
A. First power of its dimeter
B. Inverse of the fluid viscosity
C. Inverse square of the diameter
D. Square of the difference in specific weights of solid & fluid
Answer: Option B
Solution (By Examveda Team)
The terminal velocity of a small sphere settling in a viscous fluid is given by Stokes' law for low Reynolds numbers, which is expressed as:v = (2/9) * (r² * g * (ρ_s - ρ_f)) / μ
Here: v = terminal velocity r = radius of the sphere g = acceleration due to gravity ρ_s = density of the sphere ρ_f = density of the fluid μ = dynamic viscosity of the fluid
From the equation, it is evident that the terminal velocity is inversely proportional to the viscosity of the fluid (μ). A higher viscosity results in lower terminal velocity, while a lower viscosity increases the terminal velocity.
Thus, the terminal velocity varies as the inverse of the fluid viscosity.
vt=[d^2 * g * diff density]/viscosity