Two drops of equal radius coalesce to form a bigger drop. What is ratio of surface energy of bigger drop to smaller one? |
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a) |
b) |
c) |
d) |
None of the above |

Two drops of equal radius coalesce to form a bigger drop. What is ratio of surface energy of bigger drop to smaller one? |
|||||||

a) |
b) |
c) |
d) |
None of the above |

1 Answer

127 votes

**(c)**

Volume remains constant after coalescing.

Thus,

Where R is radius of bigger drop and r is radius of each smaller drop.

Now, surface energy per unit surface area is the surface tension.

So, surface energy,

Therefore, surface energy of bigger drop

Surface energy of smaller drop

Hence, required ratio

127 votes

127