The unit of surface tension in SI system is

The correct option is Newton/m.

To understand why this is the correct unit, let us define surface tension.
Surface tension is the force acting per unit length along an imaginary line drawn on the surface of a liquid.
Mathematically, surface tension ($T$) can be expressed as:

$T=\frac{F}{L}$

where:
- $F$ represents the force acting on the surface of the liquid.
- $L$ represents the length over which the force acts.

In the International System of Units (SI system):
- The SI unit of force ($F$) is the Newton ($N$).
- The SI unit of length ($L$) is the meter ($m$).

By substituting these SI units into the formula, we get the SI unit of surface tension:
$\text{SI unit of surface tension}=\frac{\text{Newton}}{\text{meter}}=\text{Newton/m}$

Thus, the unit of surface tension in the SI system is Newton/m.