Q. A spherical drop of water has 1 mm radius. If the surface tension of water is $70 \times 10^{- 3}\ Nm^{- 1}$, then the difference of pressure between inside and outside of the spherical drop is
A) $35\ Nm^{- 2}$
B) $70\ Nm^{- 2}$
C) $140\ Nm^{- 2}$
D) Zero
Explanation
(c) $p = \frac{2S}{r} = \frac{2 \times 70 \times 10^{- 3}}{10^{- 3}} = 140\ Nm^{- 2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.