Surface energy lost due to merging goes into the form of change in internal energy.
Surface energy be foce the merging = 8 × 4π (1 mm)2 × 0.073 (Nm–1 ).
The eight drops merge to forma single drop.
r = 2 mm
New surface area = 4π (2mm)2 .
Surface energy after the merger
= 4π (2mm)2 × 0.073 Nm–1
Lost surface energy
The change in internal energy is, thus, 3.67 × 10–3 J
