Light is incident on aplane mirror at an angle of 46 degrees relative to its surface. What is the angle of reflection?

Your exact answer here:
http://en.wikipedia.org/wiki/Reflection_%28physics%29

The angle of incidence equals the angle of reflection but these are relative to the normal. Geometry will tell you what the angle relative to the surface is. Be specific about what you don't understand if you repost still don't get it.
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/refln/u13l2c.html

what is the frequency of threshold of pain _____ hz