Answer: 1. Reflection: light behavior in which light waves bounce off a medium and goes in a different direction.
Refraction: light behavior in which light goes through a medium and bends, going in a different direction.
Convex: a surface shaped in such a way that the center curves outward
Concave: a surface shaped in such a way that the center curves inward
Explanation: When light bounces on a surface instead of being absorbed, then it goes in a different direction and that is called reflection while in refraction the light bends at the junction of two mediums because of varying densities.
A concave surface is one that curves inwards at the center like the interior of a circle while a convex surface is one that curves outwards like the outer part of a circle.
