Physics - Fluid Question with Solution | TestHub

Given, Excess pressure, $\Delta P=50$ dyne $/{\mathrm{cm}}^2$ Radius, $r=2\mathrm{cm}$ For a soap bubble liquid-air interface is crossed two times, so we have, Excess pressure, $\Delta P=\frac{4T}{r}$, where $\mathrm{T}$ is the surface tension. $\therefore T=\frac{\Delta P\times r}{4}=\frac{50\mathrm{dyne}/{\mathrm{cm}}^2\times 2\mathrm{cm}}{4}=25\mathrm{dyne}/\mathrm{cm}$