Q. The amount of work done to break a big water drop of radius $R$ into 27 small drops of equal radius is $10$ J. The work done required to break the same big drop into 64 small drops of equal radius will be
A) $15\,\text{J}$
B) $5\,\text{J}$
C) $20\,\text{J}$
D) $10\,\text{J}$
Explanation
[Solution by Dr. Abubacker] $W=4\pi R^2T\left(N^{1/3}-1\right)$. For $N=27$: factor $=2$; for $N=64$: factor $=3$. $W'=10\times\frac32=15$ J. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.