Question

A ray of light is incident at an angle 50 degree on the middle of one of the two mirrors arranged at an angle of 60 degree b+w them. the ray then touches the second mirror, gets reflected back to the first, making angle of incidence?​

Answer 1

All angles in degrees as placed in the above figure

From the question where C=60 and a=50.

Then b=90-a=40

b'=40

C+b'+d=180

d=180-C-b'=180-60-40=80

Then e=90-d=90-80=10

e'=10

where as C'=180-d-e-e'= 180-80-10-10=80

So the ray get touches then the second mirror gets reflected is

Therefore in a triangle XYZ we have C+d+e+e'+f=180

f=180-C-d-e-e'

=180-60-80-10-10

=20

So the making angle of incidence F is 70°

Answer 2

Both Total angles =90

A=50

B=40

angle a=90-

50=40

angle b=90-60=30

since 40+30=70