Question

a ray of light falls on a plane mirror forming of ana angle 20 degree with the mirror the devition of the ray​

Answer 1

Explanation:

As we know that when a ray of light strike on a mirror at an angle of Theta, the ray gets deviated by 2theha

i.e

angle of inclination ray = angle of reflected ray (bcoz of perpendicular formed on the plane of mirror)

now according to the question

rays angle is 20° now the deviation will be 2 times

= 40°