A large number of water drops, each of radius r, combine to have a drop of radius R. If the surface tension is T and mechanical equivalent of heat is J, the rise in heat energy per unit volume will b…

Question

A large number of water drops, each of radius r, combine to have a drop of radius R. If the surface tension is T and mechanical equivalent of heat is J, the rise in heat energy per unit volume will be:

Accepted Answer

Correct answer: D. (d) JEE Main 2021 R is the radius of bigger drop. is the radius of n water drops. Water drops are combined to make bigger drop. So, Volume o [n drops = volume of bigger drop n ( 43 r^3 )= 43 R^3 R=rn^1/3 ⇒n= ( Rr )^3 U=T(Change in surface area) U=T(n4 r^2-4 R^2) U=4 πT( ( Rr )^3r^2-R^2) ⇒ 4 πT( R^3r-R^2)J UV= 4 πT( R^3r-R^2)J 43 R^3= 3TJ( 1r- 1R)

$A large number of water drops, each of radius r, combine to have a drop of radius R . If the surface tension is T and mechanical equivalent of heat is J, the rise in heat energy per unit volume will be:$

Solution

More Fluid Mechanics PYQs