Advertisements
Advertisements
प्रश्न
Write down the expression for Stoke’s force and explain the symbols involved in it.
उत्तर
The viscous force F acting on a spherical body of radius r depends directly on:
- radius (r) of the sphere
- velocity (v) of the sphere and
- coefficient of viscosity η of the liquid
`["MLT"^-2] = "k"["ML"^-1"T"^-1]^"x" xx ["L"]^"y" xx ["LT"^-1]^"z"`
On solving, we get x = 1, y = 1 and z = 1.
Therefore, F = kη rv
Experimentally, Stoke found that the value of k = 6π
F = 6πη rv
This relation is known as Stoke’s law.
APPEARS IN
संबंधित प्रश्न
The unit of viscosity is
Which has greater viscosity, oil or honey? Why?
What is Reynold’s number? Give its significance.
Why two holes are made to empty an oil tin?
Clouds float in the air due to ______.
The velocity of a small ball of mass M and density d, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is `"d"/2`, then the viscous force acting on the ball will be ______
A solid ball of density ρ1 and radius r falls vertically through a liquid of density ρ2. Assume that the viscous force acting on the ball is F = krv, where k is a constant and v its velocity. What is the terminal velocity of the ball?
An air bubble of negligible weight having radius r rises steadily through a solution of density σ at speed v. The coefficient of viscosity of the solution is given by ______.
Define the coefficient of viscosity.
A force of 0.01 N is required to move a flat glass plate of area of 10 cm2 with a uniform velocity of 1 cm/ s over the surface of a liquid 2 mm thick. If the coefficient of viscosity of the liquid is 20 poise, the velocity gradient in the liquid layer is ______.
