Question

In activity shown below ,for an incident ray of light,if light source is rotated by an angle Ѳ,then by what angle will be the reflected ray rotated.

Answer 1

Answer:

2 times the angle

Explanation:

Construct a normal initially.

Now rotate the mirror by an angle a clockwise

notice that the new normal is at an angle a(clockwise) with old normal.

Now check the inital angle of incidence of the light ray with I mirror , let it be b intial angle of reflection is b anticlockwise with initial normal.

new angle between the normal and ray will be

c = b - a

angle of reflection is also c anticlockwise with respect to new normal

but new normal is an angle a clockwise with respect to old normal .

after all this it is simple , see all the lines , use angle sum property , and see for yourself .