8000 identical water drops are combined to form a big drop then the ratio to the final surface energy to the initial surface energy. If all the drops together is

Options

A. `1:10`
B. `1:15`
C. `1:20`
D. `1:25`

Answer

c

Explanation

Its volume remain constant
`R^(3) = 8000r^(3)` or E = 20 r
Now, `= ("Surface energy of one big drop")/("Surface energy of 8000 small drop")`
`= (4pi R^(2)T)/(8000 xx 4pi RT) = (R^(2))/(8000 r^(2)) = ((20r)^(2))/((8000r)^(2)) = (1)/(20)`