This image is a representation for light passing through a convex lens. It shows light entering from air to glass. When the light enters the glass we can see that it bends towards the normal. Now when the ray of light leaves the glass and enters the air again, we see no refraction.
What I expect:
The ray of light should bend away from normal once it exits the glass because it is going from an optically denser medium to a rarer medium.
Is it just a bad representation or the bend is negligible or I am getting something wrong?
Best Answer
They technically should "bend" because of refraction, and a more accurate drawing would be this:
But drawings like the one that you show usually just tell you the net effect of the lens, i.e. treating the lens as a black box and not a series of interfaces.
In the derivation of the thin lens equation, however, both curved surfaces, refractive indices, and radii of curvature are taken into account.