Check the accurary of the relation C` = (pi eta r^2)/(2l)` for couple per unit twist (C) of a wire of length (I), radius (r) and coefficient of rigidity (h).

Derive an expression for the rate of flow of a liquid through a capillary tube. Assume that the rate of flow depends on (i) pressure gradient (p/l) , (ii) The radius, r and (iii) the coefficient of viscosity, eta . The value of the proportionality constant k = pi/8 .

When a tension 'F' is applied, the elongation produced in uniform wire of length l, radius r is e, when tension 2F is applied, the elongation produced in another uniform wire of length 2l and radius 2r made of same material is

One end of a horizontal thick copper wire of length 2L and radius 2R is welded to an end of another horizontal thin copper wire of length L and radius R. When the arrangement is stretched by applying forces at two ends, the ratio of the elongation in the thin wire to that in the thick wire is

The volume of a liquid (v) flowing per second through a cylindrical tube depends upon the pressure gradient (p//l ) radius of the tube (r) coefficient of viscosity (eta) of the liquid by dimensional method the correct formula is