Question

Unit of surface tension is:

• A. \( \text{Nm}^{-1} \)
• B. \( \text{Nm}^{-2} \)
• C. \( \text{Nm}^{-3} \)
• D. \( \text{N}^2\text{m}^{-1} \)

Hint:

Surface tension is always expressed in terms of force per unit length, so its unit is \( \text{Nm}^{-1} \).

Answer 1

The Correct Option is A

Surface tension is defined as the force per unit length acting along the surface of a liquid. The formula for surface tension \( \gamma \) is given by: \[ \gamma = \frac{F}{L} \] where \( F \) is the force applied parallel to the surface and \( L \) is the length along which the force acts. - The SI unit of force \( F \) is Newton (N). - The SI unit of length \( L \) is meter (m). Thus, the unit of surface tension is: \[ \text{Unit of surface tension} = \frac{\text{N}}{\text{m}} = \text{Nm}^{-1} \]