Q. A soap bubble in air (two surface) has surface tension $0.03{Nm}^{- 1}$. Find the gauge pressure inside a bubble of diameter 30 mm.
A) 2 Pa
B) 4 Pa
C) 16 Pa
D) 8 Pa
Explanation
(d) $Gauge\ pressure = \frac{4T}{R} = \frac{4 \times 0.03}{\frac{30}{20} \times 10^{- 3}} = 8\ Pa$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.