Question

What is a normal unit vector?

Answer 1

The normal vector is perpendicular to the surface at a given point.

The unit vector obtained after normalizing the usual vector is the normal unit vector.

The normal unit vector is $\hat{n}=\frac{\overrightarrow{A}\times \overrightarrow{B}}{\left|\overrightarrow{A}\times \overrightarrow{B}\right|}$