The surface energy of a liquid drop is `E`. It is sprayed into `1000` equal droplets. Then its surface energy becomes

Options

A. u
B. 10u
C. 100u
D. 1000u

Answer

B

Explanation

Let R be the radius of the drop and S be the surface tension. Then
`u= S xx 4pi R^(2)`
When the drop is splitted into 1000 droplets each of radius r, then `1000 (4)/(3 ) pi r^(3)= (4)/(3) pi R^(3) or r = (R )/(10)`
`:.` Surface energy of all droplets `=S xx 1000 xx 4pi r^(2) = S xx 1000 xx 4pi ((R )/(10))^(2) = 10 (S 4pi R^(2)) = 10u`