A small metal sphere of radius 'r' and density 'ρ' falls from rest in a viscous liquid of density 'σ' and coefficient of viscosity 'η'. Which expression represents the time 't' it takes for the sphere to attain one-half of its terminal velocity (neglecting buoyancy)?

The viscous force on a lead shot travelling down with velocity V in a liquid column is F. If the same lead shot travelling down with velocity 3V in an other vertical liquid column is opposed by viscous force 2F, the ratio of the coefficients of viscosities of the liquids is

Two drops of the same radius are falling through air with a steady velocity of $5cm$ per sec. If the two drops coalesce, the terminal velocity would be

The terminal velocity of spherical ball of radius a falling through a viscous liquid is proportional to

A sphere of radius $R$ is gently dropped into liquid of viscosity ɳ in a vertical uniform tube. It attains a terminal velocity $v$. Another sphere of radius $2R$ when dropped into the same liquid, will attains its terminal velocity

Which of the following factors does NOT affect the viscous force experienced by a body moving through a fluid?

Two cylindrical vessels with their bases at the same level, contain a liquid of density $\rho$. The height of the liquid in the vessel is ${h_1}$ and in the other is ${h_2}$. The area of either base is A. The work done by the gravity in equalizing the levels when the vessels are connected.

Consider a rain drop falling through air with a terminal velocity 'v'. If the air pressure suddenly decreases but the temperature remains constant, how will the terminal velocity be affected?

A rain drop of radius $r$ falls in air with terminal velocity $v.$ What is the terminal velocity of a rain drop of radius $3r?$

A metallic sphere of mass $M$ falls through glycerine with a terminal velocity $v$. If we drop a ball of mass $8M$ of same metal into a column of glycerine, the terminal velocity of the ball will be

The coefficient of viscosity of a liquid is defined as the tangential force per unit area required to maintain a unit velocity gradient. What are the SI units of the coefficient of viscosity?