Question

A drop of liquid of diameter 2.8 mm breaks up into 125 identical drops. The change in energy is nearly (S.T. of liquid =75 dynes/cm)

• A. Zero
• B. 19 erg
• C. 46 erg
• D. 74 erg

Answer 1

Answer: (D)

74 erg

Answer 2

$E = 4 \pi R ^ { 2 } T \left( n ^ { 1 / 3 } - 1 \right)$

= $4 \times 3.14 \times \left( 1.4 \times 10 ^ { - 1 } \right) ^ { 2 } \times 75 \left( 125 ^ { 1 / 3 } - 1 \right)$