A plane wavefront incident on a reflecting surface at an angle of `30^(@)` with horizontal. Find the angle of reflected wavefront with horizontal

Explanation

Consider a plane wavefront OA incident at `30^(@)` with the horizontal. ON is normal to the reflecting surface. `anglei` is angle of incidence and `angler` is angle of reflection. According to law of reflection, `anglei = angler`
Now, from figure, we have `anglei+30^(@)=90^(@) rArr anglei=60^(@)=angler`
Angle with horizontal `=90^(@)-angle r=30^(@)`