You need to add more information
Answer: type of force is friction
Explanation:
This is best explained through the use of an optics diagram, this is a little too complicated to explain in a short answer, and as I can't draw an appropriate diagram in this answer, I will point you to this excellent resource which explains what you have asked very well!
Go onto the BBC website (you should have access to it even if you aren't in the UK) and paste this after the BBC url,
/bitesize/intermediate2/physics/waves_and_optics/image_formation_from_lens/revision/1/
Answer:
Light
Explanation:
The way a concave mirror works is that since it's concave, the light bounces off of each other. a convex mirror, it curved the opposite, and the mirror has no way to bounce off of itself.