Question

A ray gets successively reflected from two mirrors inclined at an angle 40. If the angle of incidence at first mirror is 30. Then net deviation of this ray after two reflections will be

Answer 1

Given :

Mirror are inclined at an angle 40 degrees

Angle of incidence=30°

According to laws of reflection ∠i=∠r

∴∠r=30

Angle of deviation =δ1=π-2i

=180-2x30

=180-60=140----1

Now in ΔABc

∠x=90-30=60°

from Angle sum property =

∠x+4+∠y=180

60+40+y=180

∠y=180-100=80°

incident angle on second mirror=90-80=10°

∴∠r=10°

angle of deviation =δ2=180-2i

=180-20=160-----2

Total deviation=δ1+δ2=120+160=280

Answer 2

Answer:

Explanation:

This method can also be used