Q. A spherical drop of water has radius 1 mm if surface tension of water is $70 \times 10^{- 3}\ {Nm}^{- 1}$, 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) $\mathrm{\Delta}p = \frac{2T}{r} = \frac{2 \times 70 \times 10^{- 3}}{1 \times 10^{- 3}} = 140\ {Nm}^{- 2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.