Question

what does it mean by 'normal to the surface'?​

Answer 1

Answer:

I means perpendicular or 90 degrees with the surface.

Hope this helped!

Answer 2

Answer:

It's means

The normal vector, often simply called the "normal," to a surface is a vector which is perpendicular to the surface at a given point. When normals are considered on closedsurfaces, the inward-pointing normal(pointing towards the interior of thesurface) and outward-pointing normal are usually distinguished.

Okkkk it will help u