Physics - Fluid Question with Solution | TestHub

Volume of the liquid, $V=0.04{\text{ cm}}^3$

Area of the layer, $A=20{\text{ cm}}^2$

Thickness of the liquid layer, $t=\frac{V}{A}=\frac{0.04}{20}=0.002\text{ cm}$

The force required to separate two glass plates with a thin liquid layer between them is given by:

$F=\frac{2TA}{t}$

where $T$ is the surface tension of the liquid.

Substituting the given values:

$16\times 10^5=\frac{2\times T\times 20}{0.002}$

$16\times 10^5=20000T$

$T=\frac{16\times 10^5}{2\times 10^4}=80\text{ dyne/cm}$

Answer: $80$