The terminal velocity of a copper ball of radius 2.0 mm falling through a tank of oil at `20^@C` is 6.5 cm/s. Compute the viscosity of the oil at `20^@C`. Given, `rho_(oil) = 1.5 xx 10^3 kg//m^3, rho_(copper) = 8.9 xx 10^3 kg//m^3`.

Find the ternimal velocity of a steel ball 2 mm in diameter falling through glycerine.(Sp gr. Of steel = 8 and of glycerine =1.3, viscosity of glycerine = 8.3 poise)

Determine the radius of a drop of water falling through air, if it covers 4.1 cm in 4 seconds with a uniform velocity.[density of air 0.001293 g cm^-3 , viscosity of air = 1.8xx10^-4 poise]

In Millikan’s oil drop experiment, what is the terminal speed of an uncharged drop of radius 2.0 xx 10^-5m and density 1.2 xx 10^3 kg m^-3 ? Take the viscosity of air at the temperature of the experiment to be 1.8 xx 10^-5 Pa s. How much is the viscous force on the drop at that speed? Neglect buoyancy of the drop due to air.

(a) What is the largest average velocity of blood flow in an artery of radius 2 xx10-^3 m if the flow must remain laminar? (b) What is the corresponding flow rate? (Take viscosity of blood to be 2.084 xx 10^-3 Pa s).

A man stands on vertical tower of height 20m. Calculate the distance upto which he will be able to see the surface of the earth. Given radiur of earth is 6.4xx10^3km .

Copper crystallises into a fcc lattice. Its edge length is 3.61xx10^-8 cm . Claculate the density of copper. (at mass of copper = 63.5u, N_A = 6.022xx10^23mol^-1 ).