Question

The maximum force, in addition to the weight required to pull a wire of 5.0 cm long from the surface of water at temperature ${20}^{\circ }C$ is $728dynes$. The surface tension of water is

• A. $7.28N/cm$
• B. $7.28dyne/cm$
• C. $72.8dyne/cm$
• D. $7.28\ast {10}^{2}dyne/cm$

Answer 1

The correct option is C $72.8dyne/cm$

AS we know,

$T=\frac{F}{2l}=\frac{728}{2\ast 5}$

$\therefore T=7.28dyne/cm$.