Question
Download Solution PDFWhich of the following is correct?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFExplanation:
According to Newton's law of viscosity, shear stress is directly proportional to the rate of angular deformation (shear strain) or velocity gradient across the flow.
where, τ = shear stress, μ = absolute or dynamic viscosity, du/dy = velocity gradient ⇒ dα/dt = rate of angular deformation (shear-strain).
Units of Dynamic viscosity:
∴ the unit of dynamic viscosity in the SI unit is Ns/m2 or Pa-s.
The dimension of dynamic viscosity is ML-1T-1.
1 Pa-s = 10 Poise
∴ 1 Poise = 0.1 Pa-s or Ns/m2
Kinematic viscosity:
It is defined as the ratio between the dynamic viscosity and density of the fluid.
Units of kinematic viscosity:
∴ the SI unit of kinematic viscosity is m2/s and the CGS unit of kinematic viscosity is cm2/s or 'Stoke'.
1 Stoke = 10-4 m2/s = 0.0001 m2/s.
The dimensional formula for Kinematic viscosity (ν) is ν = L2T-1.
Last updated on May 12, 2025
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