Question

What's the "normal line" when we're talking about light refraction?
And what exactly happens when light "bends"?

Answer 1

normal line is like an imaginery line drawn at 90 °

Answer 2

$\mathfrak{The\:Answer\:is}$

The 'Normal Line' is a line which is taken into consideration and is perpendicular to the surface where a ray of light strikes and refracts.

When light "bends", the phenomenon called Refraction takes place.

$\boxed{Hope\:This\:Helps}$