Is there any relationship between the incident ray and reflected
Draw a straight line ABC and angles
as shown in the figure above. The line 1 is at 60º from BD, 2 at 30º from BD.
Now , the line 4 at 60º from BD and line 3 at 30º from BD. The line BD is
perpendicular, to ABC. Hold the mirror along the line ABC. Use the mirror with
slit and make a ray go along the line 1 and reach the mirror at point B.
Observe where the reflected ray is? Is the reflected ray go along 4?
Now, try keeping the mirror with
slit and make the incident ray go along line 2. Now do we see that the
reflected ray is along line 3?
Line BD, which is perpendicular the
mirror surface is called as normal. The angle between the incident ray and the
line BD is called angle of incident. Similarly, the angle between reflected ray
and the normal is called as angle of reflection.
Can you make out relationship
between the angle of incident ray and the angle of reflected ray? Yes. Is it
not obvious that the angle of incident is same as the angle of reflection?